yanchengPowerSupply/node_modules/mux.js/dist/mux-mp4.js

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(function(f){if(typeof exports==="object"&&typeof module!=="undefined"){module.exports=f()}else if(typeof define==="function"&&define.amd){define([],f)}else{var g;if(typeof window!=="undefined"){g=window}else if(typeof global!=="undefined"){g=global}else if(typeof self!=="undefined"){g=self}else{g=this}g.muxjs = f()}})(function(){var define,module,exports;return (function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(require,module,exports){
/**
* mux.js
*
* Copyright (c) 2016 Brightcove
* All rights reserved.
*
* A stream-based aac to mp4 converter. This utility can be used to
* deliver mp4s to a SourceBuffer on platforms that support native
* Media Source Extensions.
*/
'use strict';
var Stream = require('../utils/stream.js');
// Constants
var AacStream;
/**
* Splits an incoming stream of binary data into ADTS and ID3 Frames.
*/
AacStream = function() {
var
everything = new Uint8Array(),
timeStamp = 0;
AacStream.prototype.init.call(this);
this.setTimestamp = function(timestamp) {
timeStamp = timestamp;
};
this.parseId3TagSize = function(header, byteIndex) {
var
returnSize = (header[byteIndex + 6] << 21) |
(header[byteIndex + 7] << 14) |
(header[byteIndex + 8] << 7) |
(header[byteIndex + 9]),
flags = header[byteIndex + 5],
footerPresent = (flags & 16) >> 4;
if (footerPresent) {
return returnSize + 20;
}
return returnSize + 10;
};
this.parseAdtsSize = function(header, byteIndex) {
var
lowThree = (header[byteIndex + 5] & 0xE0) >> 5,
middle = header[byteIndex + 4] << 3,
highTwo = header[byteIndex + 3] & 0x3 << 11;
return (highTwo | middle) | lowThree;
};
this.push = function(bytes) {
var
frameSize = 0,
byteIndex = 0,
bytesLeft,
chunk,
packet,
tempLength;
// If there are bytes remaining from the last segment, prepend them to the
// bytes that were pushed in
if (everything.length) {
tempLength = everything.length;
everything = new Uint8Array(bytes.byteLength + tempLength);
everything.set(everything.subarray(0, tempLength));
everything.set(bytes, tempLength);
} else {
everything = bytes;
}
while (everything.length - byteIndex >= 3) {
if ((everything[byteIndex] === 'I'.charCodeAt(0)) &&
(everything[byteIndex + 1] === 'D'.charCodeAt(0)) &&
(everything[byteIndex + 2] === '3'.charCodeAt(0))) {
// Exit early because we don't have enough to parse
// the ID3 tag header
if (everything.length - byteIndex < 10) {
break;
}
// check framesize
frameSize = this.parseId3TagSize(everything, byteIndex);
// Exit early if we don't have enough in the buffer
// to emit a full packet
if (frameSize > everything.length) {
break;
}
chunk = {
type: 'timed-metadata',
data: everything.subarray(byteIndex, byteIndex + frameSize)
};
this.trigger('data', chunk);
byteIndex += frameSize;
continue;
} else if ((everything[byteIndex] & 0xff === 0xff) &&
((everything[byteIndex + 1] & 0xf0) === 0xf0)) {
// Exit early because we don't have enough to parse
// the ADTS frame header
if (everything.length - byteIndex < 7) {
break;
}
frameSize = this.parseAdtsSize(everything, byteIndex);
// Exit early if we don't have enough in the buffer
// to emit a full packet
if (frameSize > everything.length) {
break;
}
packet = {
type: 'audio',
data: everything.subarray(byteIndex, byteIndex + frameSize),
pts: timeStamp,
dts: timeStamp
};
this.trigger('data', packet);
byteIndex += frameSize;
continue;
}
byteIndex++;
}
bytesLeft = everything.length - byteIndex;
if (bytesLeft > 0) {
everything = everything.subarray(byteIndex);
} else {
everything = new Uint8Array();
}
};
};
AacStream.prototype = new Stream();
module.exports = AacStream;
},{"../utils/stream.js":15}],2:[function(require,module,exports){
'use strict';
var Stream = require('../utils/stream.js');
var AdtsStream;
var
ADTS_SAMPLING_FREQUENCIES = [
96000,
88200,
64000,
48000,
44100,
32000,
24000,
22050,
16000,
12000,
11025,
8000,
7350
];
/*
* Accepts a ElementaryStream and emits data events with parsed
* AAC Audio Frames of the individual packets. Input audio in ADTS
* format is unpacked and re-emitted as AAC frames.
*
* @see http://wiki.multimedia.cx/index.php?title=ADTS
* @see http://wiki.multimedia.cx/?title=Understanding_AAC
*/
AdtsStream = function() {
var buffer;
AdtsStream.prototype.init.call(this);
this.push = function(packet) {
var
i = 0,
frameNum = 0,
frameLength,
protectionSkipBytes,
frameEnd,
oldBuffer,
sampleCount,
adtsFrameDuration;
if (packet.type !== 'audio') {
// ignore non-audio data
return;
}
// Prepend any data in the buffer to the input data so that we can parse
// aac frames the cross a PES packet boundary
if (buffer) {
oldBuffer = buffer;
buffer = new Uint8Array(oldBuffer.byteLength + packet.data.byteLength);
buffer.set(oldBuffer);
buffer.set(packet.data, oldBuffer.byteLength);
} else {
buffer = packet.data;
}
// unpack any ADTS frames which have been fully received
// for details on the ADTS header, see http://wiki.multimedia.cx/index.php?title=ADTS
while (i + 5 < buffer.length) {
// Loook for the start of an ADTS header..
if (buffer[i] !== 0xFF || (buffer[i + 1] & 0xF6) !== 0xF0) {
// If a valid header was not found, jump one forward and attempt to
// find a valid ADTS header starting at the next byte
i++;
continue;
}
// The protection skip bit tells us if we have 2 bytes of CRC data at the
// end of the ADTS header
protectionSkipBytes = (~buffer[i + 1] & 0x01) * 2;
// Frame length is a 13 bit integer starting 16 bits from the
// end of the sync sequence
frameLength = ((buffer[i + 3] & 0x03) << 11) |
(buffer[i + 4] << 3) |
((buffer[i + 5] & 0xe0) >> 5);
sampleCount = ((buffer[i + 6] & 0x03) + 1) * 1024;
adtsFrameDuration = (sampleCount * 90000) /
ADTS_SAMPLING_FREQUENCIES[(buffer[i + 2] & 0x3c) >>> 2];
frameEnd = i + frameLength;
// If we don't have enough data to actually finish this ADTS frame, return
// and wait for more data
if (buffer.byteLength < frameEnd) {
return;
}
// Otherwise, deliver the complete AAC frame
this.trigger('data', {
pts: packet.pts + (frameNum * adtsFrameDuration),
dts: packet.dts + (frameNum * adtsFrameDuration),
sampleCount: sampleCount,
audioobjecttype: ((buffer[i + 2] >>> 6) & 0x03) + 1,
channelcount: ((buffer[i + 2] & 1) << 2) |
((buffer[i + 3] & 0xc0) >>> 6),
samplerate: ADTS_SAMPLING_FREQUENCIES[(buffer[i + 2] & 0x3c) >>> 2],
samplingfrequencyindex: (buffer[i + 2] & 0x3c) >>> 2,
// assume ISO/IEC 14496-12 AudioSampleEntry default of 16
samplesize: 16,
data: buffer.subarray(i + 7 + protectionSkipBytes, frameEnd)
});
// If the buffer is empty, clear it and return
if (buffer.byteLength === frameEnd) {
buffer = undefined;
return;
}
frameNum++;
// Remove the finished frame from the buffer and start the process again
buffer = buffer.subarray(frameEnd);
}
};
this.flush = function() {
this.trigger('done');
};
};
AdtsStream.prototype = new Stream();
module.exports = AdtsStream;
},{"../utils/stream.js":15}],3:[function(require,module,exports){
'use strict';
var Stream = require('../utils/stream.js');
var ExpGolomb = require('../utils/exp-golomb.js');
var H264Stream, NalByteStream;
var PROFILES_WITH_OPTIONAL_SPS_DATA;
/**
* Accepts a NAL unit byte stream and unpacks the embedded NAL units.
*/
NalByteStream = function() {
var
syncPoint = 0,
i,
buffer;
NalByteStream.prototype.init.call(this);
this.push = function(data) {
var swapBuffer;
if (!buffer) {
buffer = data.data;
} else {
swapBuffer = new Uint8Array(buffer.byteLength + data.data.byteLength);
swapBuffer.set(buffer);
swapBuffer.set(data.data, buffer.byteLength);
buffer = swapBuffer;
}
// Rec. ITU-T H.264, Annex B
// scan for NAL unit boundaries
// a match looks like this:
// 0 0 1 .. NAL .. 0 0 1
// ^ sync point ^ i
// or this:
// 0 0 1 .. NAL .. 0 0 0
// ^ sync point ^ i
// advance the sync point to a NAL start, if necessary
for (; syncPoint < buffer.byteLength - 3; syncPoint++) {
if (buffer[syncPoint + 2] === 1) {
// the sync point is properly aligned
i = syncPoint + 5;
break;
}
}
while (i < buffer.byteLength) {
// look at the current byte to determine if we've hit the end of
// a NAL unit boundary
switch (buffer[i]) {
case 0:
// skip past non-sync sequences
if (buffer[i - 1] !== 0) {
i += 2;
break;
} else if (buffer[i - 2] !== 0) {
i++;
break;
}
// deliver the NAL unit if it isn't empty
if (syncPoint + 3 !== i - 2) {
this.trigger('data', buffer.subarray(syncPoint + 3, i - 2));
}
// drop trailing zeroes
do {
i++;
} while (buffer[i] !== 1 && i < buffer.length);
syncPoint = i - 2;
i += 3;
break;
case 1:
// skip past non-sync sequences
if (buffer[i - 1] !== 0 ||
buffer[i - 2] !== 0) {
i += 3;
break;
}
// deliver the NAL unit
this.trigger('data', buffer.subarray(syncPoint + 3, i - 2));
syncPoint = i - 2;
i += 3;
break;
default:
// the current byte isn't a one or zero, so it cannot be part
// of a sync sequence
i += 3;
break;
}
}
// filter out the NAL units that were delivered
buffer = buffer.subarray(syncPoint);
i -= syncPoint;
syncPoint = 0;
};
this.flush = function() {
// deliver the last buffered NAL unit
if (buffer && buffer.byteLength > 3) {
this.trigger('data', buffer.subarray(syncPoint + 3));
}
// reset the stream state
buffer = null;
syncPoint = 0;
this.trigger('done');
};
};
NalByteStream.prototype = new Stream();
// values of profile_idc that indicate additional fields are included in the SPS
// see Recommendation ITU-T H.264 (4/2013),
// 7.3.2.1.1 Sequence parameter set data syntax
PROFILES_WITH_OPTIONAL_SPS_DATA = {
100: true,
110: true,
122: true,
244: true,
44: true,
83: true,
86: true,
118: true,
128: true,
138: true,
139: true,
134: true
};
/**
* Accepts input from a ElementaryStream and produces H.264 NAL unit data
* events.
*/
H264Stream = function() {
var
nalByteStream = new NalByteStream(),
self,
trackId,
currentPts,
currentDts,
discardEmulationPreventionBytes,
readSequenceParameterSet,
skipScalingList;
H264Stream.prototype.init.call(this);
self = this;
this.push = function(packet) {
if (packet.type !== 'video') {
return;
}
trackId = packet.trackId;
currentPts = packet.pts;
currentDts = packet.dts;
nalByteStream.push(packet);
};
nalByteStream.on('data', function(data) {
var
event = {
trackId: trackId,
pts: currentPts,
dts: currentDts,
data: data
};
switch (data[0] & 0x1f) {
case 0x05:
event.nalUnitType = 'slice_layer_without_partitioning_rbsp_idr';
break;
case 0x06:
event.nalUnitType = 'sei_rbsp';
event.escapedRBSP = discardEmulationPreventionBytes(data.subarray(1));
break;
case 0x07:
event.nalUnitType = 'seq_parameter_set_rbsp';
event.escapedRBSP = discardEmulationPreventionBytes(data.subarray(1));
event.config = readSequenceParameterSet(event.escapedRBSP);
break;
case 0x08:
event.nalUnitType = 'pic_parameter_set_rbsp';
break;
case 0x09:
event.nalUnitType = 'access_unit_delimiter_rbsp';
break;
default:
break;
}
self.trigger('data', event);
});
nalByteStream.on('done', function() {
self.trigger('done');
});
this.flush = function() {
nalByteStream.flush();
};
/**
* Advance the ExpGolomb decoder past a scaling list. The scaling
* list is optionally transmitted as part of a sequence parameter
* set and is not relevant to transmuxing.
* @param count {number} the number of entries in this scaling list
* @param expGolombDecoder {object} an ExpGolomb pointed to the
* start of a scaling list
* @see Recommendation ITU-T H.264, Section 7.3.2.1.1.1
*/
skipScalingList = function(count, expGolombDecoder) {
var
lastScale = 8,
nextScale = 8,
j,
deltaScale;
for (j = 0; j < count; j++) {
if (nextScale !== 0) {
deltaScale = expGolombDecoder.readExpGolomb();
nextScale = (lastScale + deltaScale + 256) % 256;
}
lastScale = (nextScale === 0) ? lastScale : nextScale;
}
};
/**
* Expunge any "Emulation Prevention" bytes from a "Raw Byte
* Sequence Payload"
* @param data {Uint8Array} the bytes of a RBSP from a NAL
* unit
* @return {Uint8Array} the RBSP without any Emulation
* Prevention Bytes
*/
discardEmulationPreventionBytes = function(data) {
var
length = data.byteLength,
emulationPreventionBytesPositions = [],
i = 1,
newLength, newData;
// Find all `Emulation Prevention Bytes`
while (i < length - 2) {
if (data[i] === 0 && data[i + 1] === 0 && data[i + 2] === 0x03) {
emulationPreventionBytesPositions.push(i + 2);
i += 2;
} else {
i++;
}
}
// If no Emulation Prevention Bytes were found just return the original
// array
if (emulationPreventionBytesPositions.length === 0) {
return data;
}
// Create a new array to hold the NAL unit data
newLength = length - emulationPreventionBytesPositions.length;
newData = new Uint8Array(newLength);
var sourceIndex = 0;
for (i = 0; i < newLength; sourceIndex++, i++) {
if (sourceIndex === emulationPreventionBytesPositions[0]) {
// Skip this byte
sourceIndex++;
// Remove this position index
emulationPreventionBytesPositions.shift();
}
newData[i] = data[sourceIndex];
}
return newData;
};
/**
* Read a sequence parameter set and return some interesting video
* properties. A sequence parameter set is the H264 metadata that
* describes the properties of upcoming video frames.
* @param data {Uint8Array} the bytes of a sequence parameter set
* @return {object} an object with configuration parsed from the
* sequence parameter set, including the dimensions of the
* associated video frames.
*/
readSequenceParameterSet = function(data) {
var
frameCropLeftOffset = 0,
frameCropRightOffset = 0,
frameCropTopOffset = 0,
frameCropBottomOffset = 0,
sarScale = 1,
expGolombDecoder, profileIdc, levelIdc, profileCompatibility,
chromaFormatIdc, picOrderCntType,
numRefFramesInPicOrderCntCycle, picWidthInMbsMinus1,
picHeightInMapUnitsMinus1,
frameMbsOnlyFlag,
scalingListCount,
sarRatio,
aspectRatioIdc,
i;
expGolombDecoder = new ExpGolomb(data);
profileIdc = expGolombDecoder.readUnsignedByte(); // profile_idc
profileCompatibility = expGolombDecoder.readUnsignedByte(); // constraint_set[0-5]_flag
levelIdc = expGolombDecoder.readUnsignedByte(); // level_idc u(8)
expGolombDecoder.skipUnsignedExpGolomb(); // seq_parameter_set_id
// some profiles have more optional data we don't need
if (PROFILES_WITH_OPTIONAL_SPS_DATA[profileIdc]) {
chromaFormatIdc = expGolombDecoder.readUnsignedExpGolomb();
if (chromaFormatIdc === 3) {
expGolombDecoder.skipBits(1); // separate_colour_plane_flag
}
expGolombDecoder.skipUnsignedExpGolomb(); // bit_depth_luma_minus8
expGolombDecoder.skipUnsignedExpGolomb(); // bit_depth_chroma_minus8
expGolombDecoder.skipBits(1); // qpprime_y_zero_transform_bypass_flag
if (expGolombDecoder.readBoolean()) { // seq_scaling_matrix_present_flag
scalingListCount = (chromaFormatIdc !== 3) ? 8 : 12;
for (i = 0; i < scalingListCount; i++) {
if (expGolombDecoder.readBoolean()) { // seq_scaling_list_present_flag[ i ]
if (i < 6) {
skipScalingList(16, expGolombDecoder);
} else {
skipScalingList(64, expGolombDecoder);
}
}
}
}
}
expGolombDecoder.skipUnsignedExpGolomb(); // log2_max_frame_num_minus4
picOrderCntType = expGolombDecoder.readUnsignedExpGolomb();
if (picOrderCntType === 0) {
expGolombDecoder.readUnsignedExpGolomb(); // log2_max_pic_order_cnt_lsb_minus4
} else if (picOrderCntType === 1) {
expGolombDecoder.skipBits(1); // delta_pic_order_always_zero_flag
expGolombDecoder.skipExpGolomb(); // offset_for_non_ref_pic
expGolombDecoder.skipExpGolomb(); // offset_for_top_to_bottom_field
numRefFramesInPicOrderCntCycle = expGolombDecoder.readUnsignedExpGolomb();
for (i = 0; i < numRefFramesInPicOrderCntCycle; i++) {
expGolombDecoder.skipExpGolomb(); // offset_for_ref_frame[ i ]
}
}
expGolombDecoder.skipUnsignedExpGolomb(); // max_num_ref_frames
expGolombDecoder.skipBits(1); // gaps_in_frame_num_value_allowed_flag
picWidthInMbsMinus1 = expGolombDecoder.readUnsignedExpGolomb();
picHeightInMapUnitsMinus1 = expGolombDecoder.readUnsignedExpGolomb();
frameMbsOnlyFlag = expGolombDecoder.readBits(1);
if (frameMbsOnlyFlag === 0) {
expGolombDecoder.skipBits(1); // mb_adaptive_frame_field_flag
}
expGolombDecoder.skipBits(1); // direct_8x8_inference_flag
if (expGolombDecoder.readBoolean()) { // frame_cropping_flag
frameCropLeftOffset = expGolombDecoder.readUnsignedExpGolomb();
frameCropRightOffset = expGolombDecoder.readUnsignedExpGolomb();
frameCropTopOffset = expGolombDecoder.readUnsignedExpGolomb();
frameCropBottomOffset = expGolombDecoder.readUnsignedExpGolomb();
}
if (expGolombDecoder.readBoolean()) {
// vui_parameters_present_flag
if (expGolombDecoder.readBoolean()) {
// aspect_ratio_info_present_flag
aspectRatioIdc = expGolombDecoder.readUnsignedByte();
switch (aspectRatioIdc) {
case 1: sarRatio = [1, 1]; break;
case 2: sarRatio = [12, 11]; break;
case 3: sarRatio = [10, 11]; break;
case 4: sarRatio = [16, 11]; break;
case 5: sarRatio = [40, 33]; break;
case 6: sarRatio = [24, 11]; break;
case 7: sarRatio = [20, 11]; break;
case 8: sarRatio = [32, 11]; break;
case 9: sarRatio = [80, 33]; break;
case 10: sarRatio = [18, 11]; break;
case 11: sarRatio = [15, 11]; break;
case 12: sarRatio = [64, 33]; break;
case 13: sarRatio = [160, 99]; break;
case 14: sarRatio = [4, 3]; break;
case 15: sarRatio = [3, 2]; break;
case 16: sarRatio = [2, 1]; break;
case 255: {
sarRatio = [expGolombDecoder.readUnsignedByte() << 8 |
expGolombDecoder.readUnsignedByte(),
expGolombDecoder.readUnsignedByte() << 8 |
expGolombDecoder.readUnsignedByte() ];
break;
}
}
if (sarRatio) {
sarScale = sarRatio[0] / sarRatio[1];
}
}
}
return {
profileIdc: profileIdc,
levelIdc: levelIdc,
profileCompatibility: profileCompatibility,
width: Math.ceil((((picWidthInMbsMinus1 + 1) * 16) - frameCropLeftOffset * 2 - frameCropRightOffset * 2) * sarScale),
height: ((2 - frameMbsOnlyFlag) * (picHeightInMapUnitsMinus1 + 1) * 16) - (frameCropTopOffset * 2) - (frameCropBottomOffset * 2)
};
};
};
H264Stream.prototype = new Stream();
module.exports = {
H264Stream: H264Stream,
NalByteStream: NalByteStream
};
},{"../utils/exp-golomb.js":14,"../utils/stream.js":15}],4:[function(require,module,exports){
var highPrefix = [33, 16, 5, 32, 164, 27];
var lowPrefix = [33, 65, 108, 84, 1, 2, 4, 8, 168, 2, 4, 8, 17, 191, 252];
var zeroFill = function(count) {
var a = [];
while (count--) {
a.push(0);
}
return a;
};
var makeTable = function(metaTable) {
return Object.keys(metaTable).reduce(function(obj, key) {
obj[key] = new Uint8Array(metaTable[key].reduce(function(arr, part) {
return arr.concat(part);
}, []));
return obj;
}, {});
};
// Frames-of-silence to use for filling in missing AAC frames
var coneOfSilence = {
96000: [highPrefix, [227, 64], zeroFill(154), [56]],
88200: [highPrefix, [231], zeroFill(170), [56]],
64000: [highPrefix, [248, 192], zeroFill(240), [56]],
48000: [highPrefix, [255, 192], zeroFill(268), [55, 148, 128], zeroFill(54), [112]],
44100: [highPrefix, [255, 192], zeroFill(268), [55, 163, 128], zeroFill(84), [112]],
32000: [highPrefix, [255, 192], zeroFill(268), [55, 234], zeroFill(226), [112]],
24000: [highPrefix, [255, 192], zeroFill(268), [55, 255, 128], zeroFill(268), [111, 112], zeroFill(126), [224]],
16000: [highPrefix, [255, 192], zeroFill(268), [55, 255, 128], zeroFill(268), [111, 255], zeroFill(269), [223, 108], zeroFill(195), [1, 192]],
12000: [lowPrefix, zeroFill(268), [3, 127, 248], zeroFill(268), [6, 255, 240], zeroFill(268), [13, 255, 224], zeroFill(268), [27, 253, 128], zeroFill(259), [56]],
11025: [lowPrefix, zeroFill(268), [3, 127, 248], zeroFill(268), [6, 255, 240], zeroFill(268), [13, 255, 224], zeroFill(268), [27, 255, 192], zeroFill(268), [55, 175, 128], zeroFill(108), [112]],
8000: [lowPrefix, zeroFill(268), [3, 121, 16], zeroFill(47), [7]]
};
module.exports = makeTable(coneOfSilence);
},{}],5:[function(require,module,exports){
/**
* mux.js
*
* Copyright (c) 2015 Brightcove
* All rights reserved.
*
* Reads in-band caption information from a video elementary
* stream. Captions must follow the CEA-708 standard for injection
* into an MPEG-2 transport streams.
* @see https://en.wikipedia.org/wiki/CEA-708
* @see https://www.gpo.gov/fdsys/pkg/CFR-2007-title47-vol1/pdf/CFR-2007-title47-vol1-sec15-119.pdf
*/
'use strict';
// -----------------
// Link To Transport
// -----------------
// Supplemental enhancement information (SEI) NAL units have a
// payload type field to indicate how they are to be
// interpreted. CEAS-708 caption content is always transmitted with
// payload type 0x04.
var USER_DATA_REGISTERED_ITU_T_T35 = 4,
RBSP_TRAILING_BITS = 128,
Stream = require('../utils/stream');
/**
* Parse a supplemental enhancement information (SEI) NAL unit.
* Stops parsing once a message of type ITU T T35 has been found.
*
* @param bytes {Uint8Array} the bytes of a SEI NAL unit
* @return {object} the parsed SEI payload
* @see Rec. ITU-T H.264, 7.3.2.3.1
*/
var parseSei = function(bytes) {
var
i = 0,
result = {
payloadType: -1,
payloadSize: 0
},
payloadType = 0,
payloadSize = 0;
// go through the sei_rbsp parsing each each individual sei_message
while (i < bytes.byteLength) {
// stop once we have hit the end of the sei_rbsp
if (bytes[i] === RBSP_TRAILING_BITS) {
break;
}
// Parse payload type
while (bytes[i] === 0xFF) {
payloadType += 255;
i++;
}
payloadType += bytes[i++];
// Parse payload size
while (bytes[i] === 0xFF) {
payloadSize += 255;
i++;
}
payloadSize += bytes[i++];
// this sei_message is a 608/708 caption so save it and break
// there can only ever be one caption message in a frame's sei
if (!result.payload && payloadType === USER_DATA_REGISTERED_ITU_T_T35) {
result.payloadType = payloadType;
result.payloadSize = payloadSize;
result.payload = bytes.subarray(i, i + payloadSize);
break;
}
// skip the payload and parse the next message
i += payloadSize;
payloadType = 0;
payloadSize = 0;
}
return result;
};
// see ANSI/SCTE 128-1 (2013), section 8.1
var parseUserData = function(sei) {
// itu_t_t35_contry_code must be 181 (United States) for
// captions
if (sei.payload[0] !== 181) {
return null;
}
// itu_t_t35_provider_code should be 49 (ATSC) for captions
if (((sei.payload[1] << 8) | sei.payload[2]) !== 49) {
return null;
}
// the user_identifier should be "GA94" to indicate ATSC1 data
if (String.fromCharCode(sei.payload[3],
sei.payload[4],
sei.payload[5],
sei.payload[6]) !== 'GA94') {
return null;
}
// finally, user_data_type_code should be 0x03 for caption data
if (sei.payload[7] !== 0x03) {
return null;
}
// return the user_data_type_structure and strip the trailing
// marker bits
return sei.payload.subarray(8, sei.payload.length - 1);
};
// see CEA-708-D, section 4.4
var parseCaptionPackets = function(pts, userData) {
var results = [], i, count, offset, data;
// if this is just filler, return immediately
if (!(userData[0] & 0x40)) {
return results;
}
// parse out the cc_data_1 and cc_data_2 fields
count = userData[0] & 0x1f;
for (i = 0; i < count; i++) {
offset = i * 3;
data = {
type: userData[offset + 2] & 0x03,
pts: pts
};
// capture cc data when cc_valid is 1
if (userData[offset + 2] & 0x04) {
data.ccData = (userData[offset + 3] << 8) | userData[offset + 4];
results.push(data);
}
}
return results;
};
var CaptionStream = function() {
CaptionStream.prototype.init.call(this);
this.captionPackets_ = [];
this.ccStreams_ = [
new Cea608Stream(0, 0), // eslint-disable-line no-use-before-define
new Cea608Stream(0, 1), // eslint-disable-line no-use-before-define
new Cea608Stream(1, 0), // eslint-disable-line no-use-before-define
new Cea608Stream(1, 1) // eslint-disable-line no-use-before-define
];
this.reset();
// forward data and done events from CCs to this CaptionStream
this.ccStreams_.forEach(function(cc) {
cc.on('data', this.trigger.bind(this, 'data'));
cc.on('done', this.trigger.bind(this, 'done'));
}, this);
};
CaptionStream.prototype = new Stream();
CaptionStream.prototype.push = function(event) {
var sei, userData;
// only examine SEI NALs
if (event.nalUnitType !== 'sei_rbsp') {
return;
}
// parse the sei
sei = parseSei(event.escapedRBSP);
// ignore everything but user_data_registered_itu_t_t35
if (sei.payloadType !== USER_DATA_REGISTERED_ITU_T_T35) {
return;
}
// parse out the user data payload
userData = parseUserData(sei);
// ignore unrecognized userData
if (!userData) {
return;
}
// Sometimes, the same segment # will be downloaded twice. To stop the
// caption data from being processed twice, we track the latest dts we've
// received and ignore everything with a dts before that. However, since
// data for a specific dts can be split across 2 packets on either side of
// a segment boundary, we need to make sure we *don't* ignore the second
// dts packet we receive that has dts === this.latestDts_. And thus, the
// ignoreNextEqualDts_ flag was born.
if (event.dts < this.latestDts_) {
// We've started getting older data, so set the flag.
this.ignoreNextEqualDts_ = true;
return;
} else if ((event.dts === this.latestDts_) && (this.ignoreNextEqualDts_)) {
// We've received the last duplicate packet, time to start processing again
this.ignoreNextEqualDts_ = false;
return;
}
// parse out CC data packets and save them for later
this.captionPackets_ = this.captionPackets_.concat(parseCaptionPackets(event.pts, userData));
this.latestDts_ = event.dts;
};
CaptionStream.prototype.flush = function() {
// make sure we actually parsed captions before proceeding
if (!this.captionPackets_.length) {
this.ccStreams_.forEach(function(cc) {
cc.flush();
}, this);
return;
}
// In Chrome, the Array#sort function is not stable so add a
// presortIndex that we can use to ensure we get a stable-sort
this.captionPackets_.forEach(function(elem, idx) {
elem.presortIndex = idx;
});
// sort caption byte-pairs based on their PTS values
this.captionPackets_.sort(function(a, b) {
if (a.pts === b.pts) {
return a.presortIndex - b.presortIndex;
}
return a.pts - b.pts;
});
this.captionPackets_.forEach(function(packet) {
if (packet.type < 2) {
// Dispatch packet to the right Cea608Stream
this.dispatchCea608Packet(packet);
}
// this is where an 'else' would go for a dispatching packets
// to a theoretical Cea708Stream that handles SERVICEn data
}, this);
this.captionPackets_.length = 0;
this.ccStreams_.forEach(function(cc) {
cc.flush();
}, this);
return;
};
CaptionStream.prototype.reset = function() {
this.latestDts_ = null;
this.ignoreNextEqualDts_ = false;
this.activeCea608Channel_ = [null, null];
this.ccStreams_.forEach(function(ccStream) {
ccStream.reset();
});
};
CaptionStream.prototype.dispatchCea608Packet = function(packet) {
// NOTE: packet.type is the CEA608 field
if (this.setsChannel1Active(packet)) {
this.activeCea608Channel_[packet.type] = 0;
} else if (this.setsChannel2Active(packet)) {
this.activeCea608Channel_[packet.type] = 1;
}
if (this.activeCea608Channel_[packet.type] === null) {
// If we haven't received anything to set the active channel, discard the
// data; we don't want jumbled captions
return;
}
this.ccStreams_[(packet.type << 1) + this.activeCea608Channel_[packet.type]].push(packet);
};
CaptionStream.prototype.setsChannel1Active = function(packet) {
return ((packet.ccData & 0x7800) === 0x1000);
};
CaptionStream.prototype.setsChannel2Active = function(packet) {
return ((packet.ccData & 0x7800) === 0x1800);
};
// ----------------------
// Session to Application
// ----------------------
var CHARACTER_TRANSLATION = {
0x2a: 0xe1, // á
0x5c: 0xe9, // é
0x5e: 0xed, // í
0x5f: 0xf3, // ó
0x60: 0xfa, // ú
0x7b: 0xe7, // ç
0x7c: 0xf7, // ÷
0x7d: 0xd1, // Ñ
0x7e: 0xf1, // ñ
0x7f: 0x2588, // █
0x0130: 0xae, // ®
0x0131: 0xb0, // °
0x0132: 0xbd, // ½
0x0133: 0xbf, // ¿
0x0134: 0x2122, // ™
0x0135: 0xa2, // ¢
0x0136: 0xa3, // £
0x0137: 0x266a, // ♪
0x0138: 0xe0, // à
0x0139: 0xa0, //
0x013a: 0xe8, // è
0x013b: 0xe2, // â
0x013c: 0xea, // ê
0x013d: 0xee, // î
0x013e: 0xf4, // ô
0x013f: 0xfb, // û
0x0220: 0xc1, // Á
0x0221: 0xc9, // É
0x0222: 0xd3, // Ó
0x0223: 0xda, // Ú
0x0224: 0xdc, // Ü
0x0225: 0xfc, // ü
0x0226: 0x2018, //
0x0227: 0xa1, // ¡
0x0228: 0x2a, // *
0x0229: 0x27, // '
0x022a: 0x2014, // —
0x022b: 0xa9, // ©
0x022c: 0x2120, // ℠
0x022d: 0x2022, // •
0x022e: 0x201c, // “
0x022f: 0x201d, // ”
0x0230: 0xc0, // À
0x0231: 0xc2, // Â
0x0232: 0xc7, // Ç
0x0233: 0xc8, // È
0x0234: 0xca, // Ê
0x0235: 0xcb, // Ë
0x0236: 0xeb, // ë
0x0237: 0xce, // Î
0x0238: 0xcf, // Ï
0x0239: 0xef, // ï
0x023a: 0xd4, // Ô
0x023b: 0xd9, // Ù
0x023c: 0xf9, // ù
0x023d: 0xdb, // Û
0x023e: 0xab, // «
0x023f: 0xbb, // »
0x0320: 0xc3, // Ã
0x0321: 0xe3, // ã
0x0322: 0xcd, // Í
0x0323: 0xcc, // Ì
0x0324: 0xec, // ì
0x0325: 0xd2, // Ò
0x0326: 0xf2, // ò
0x0327: 0xd5, // Õ
0x0328: 0xf5, // õ
0x0329: 0x7b, // {
0x032a: 0x7d, // }
0x032b: 0x5c, // \
0x032c: 0x5e, // ^
0x032d: 0x5f, // _
0x032e: 0x7c, // |
0x032f: 0x7e, // ~
0x0330: 0xc4, // Ä
0x0331: 0xe4, // ä
0x0332: 0xd6, // Ö
0x0333: 0xf6, // ö
0x0334: 0xdf, // ß
0x0335: 0xa5, // ¥
0x0336: 0xa4, // ¤
0x0337: 0x2502, // │
0x0338: 0xc5, // Å
0x0339: 0xe5, // å
0x033a: 0xd8, // Ø
0x033b: 0xf8, // ø
0x033c: 0x250c, // ┌
0x033d: 0x2510, // ┐
0x033e: 0x2514, // └
0x033f: 0x2518 // ┘
};
var getCharFromCode = function(code) {
if (code === null) {
return '';
}
code = CHARACTER_TRANSLATION[code] || code;
return String.fromCharCode(code);
};
// the index of the last row in a CEA-608 display buffer
var BOTTOM_ROW = 14;
// This array is used for mapping PACs -> row #, since there's no way of
// getting it through bit logic.
var ROWS = [0x1100, 0x1120, 0x1200, 0x1220, 0x1500, 0x1520, 0x1600, 0x1620,
0x1700, 0x1720, 0x1000, 0x1300, 0x1320, 0x1400, 0x1420];
// CEA-608 captions are rendered onto a 34x15 matrix of character
// cells. The "bottom" row is the last element in the outer array.
var createDisplayBuffer = function() {
var result = [], i = BOTTOM_ROW + 1;
while (i--) {
result.push('');
}
return result;
};
var Cea608Stream = function(field, dataChannel) {
Cea608Stream.prototype.init.call(this);
this.field_ = field || 0;
this.dataChannel_ = dataChannel || 0;
this.name_ = 'CC' + (((this.field_ << 1) | this.dataChannel_) + 1);
this.setConstants();
this.reset();
this.push = function(packet) {
var data, swap, char0, char1, text;
// remove the parity bits
data = packet.ccData & 0x7f7f;
// ignore duplicate control codes; the spec demands they're sent twice
if (data === this.lastControlCode_) {
this.lastControlCode_ = null;
return;
}
// Store control codes
if ((data & 0xf000) === 0x1000) {
this.lastControlCode_ = data;
} else if (data !== this.PADDING_) {
this.lastControlCode_ = null;
}
char0 = data >>> 8;
char1 = data & 0xff;
if (data === this.PADDING_) {
return;
} else if (data === this.RESUME_CAPTION_LOADING_) {
this.mode_ = 'popOn';
} else if (data === this.END_OF_CAPTION_) {
this.clearFormatting(packet.pts);
// if a caption was being displayed, it's gone now
this.flushDisplayed(packet.pts);
// flip memory
swap = this.displayed_;
this.displayed_ = this.nonDisplayed_;
this.nonDisplayed_ = swap;
// start measuring the time to display the caption
this.startPts_ = packet.pts;
} else if (data === this.ROLL_UP_2_ROWS_) {
this.topRow_ = BOTTOM_ROW - 1;
this.mode_ = 'rollUp';
} else if (data === this.ROLL_UP_3_ROWS_) {
this.topRow_ = BOTTOM_ROW - 2;
this.mode_ = 'rollUp';
} else if (data === this.ROLL_UP_4_ROWS_) {
this.topRow_ = BOTTOM_ROW - 3;
this.mode_ = 'rollUp';
} else if (data === this.CARRIAGE_RETURN_) {
this.clearFormatting(packet.pts);
this.flushDisplayed(packet.pts);
this.shiftRowsUp_();
this.startPts_ = packet.pts;
} else if (data === this.BACKSPACE_) {
if (this.mode_ === 'popOn') {
this.nonDisplayed_[BOTTOM_ROW] = this.nonDisplayed_[BOTTOM_ROW].slice(0, -1);
} else {
this.displayed_[BOTTOM_ROW] = this.displayed_[BOTTOM_ROW].slice(0, -1);
}
} else if (data === this.ERASE_DISPLAYED_MEMORY_) {
this.flushDisplayed(packet.pts);
this.displayed_ = createDisplayBuffer();
} else if (data === this.ERASE_NON_DISPLAYED_MEMORY_) {
this.nonDisplayed_ = createDisplayBuffer();
} else if (data === this.RESUME_DIRECT_CAPTIONING_) {
this.mode_ = 'paintOn';
// Append special characters to caption text
} else if (this.isSpecialCharacter(char0, char1)) {
// Bitmask char0 so that we can apply character transformations
// regardless of field and data channel.
// Then byte-shift to the left and OR with char1 so we can pass the
// entire character code to `getCharFromCode`.
char0 = (char0 & 0x03) << 8;
text = getCharFromCode(char0 | char1);
this[this.mode_](packet.pts, text);
this.column_++;
// Append extended characters to caption text
} else if (this.isExtCharacter(char0, char1)) {
// Extended characters always follow their "non-extended" equivalents.
// IE if a "è" is desired, you'll always receive "eè"; non-compliant
// decoders are supposed to drop the "è", while compliant decoders
// backspace the "e" and insert "è".
// Delete the previous character
if (this.mode_ === 'popOn') {
this.nonDisplayed_[this.row_] = this.nonDisplayed_[this.row_].slice(0, -1);
} else {
this.displayed_[BOTTOM_ROW] = this.displayed_[BOTTOM_ROW].slice(0, -1);
}
// Bitmask char0 so that we can apply character transformations
// regardless of field and data channel.
// Then byte-shift to the left and OR with char1 so we can pass the
// entire character code to `getCharFromCode`.
char0 = (char0 & 0x03) << 8;
text = getCharFromCode(char0 | char1);
this[this.mode_](packet.pts, text);
this.column_++;
// Process mid-row codes
} else if (this.isMidRowCode(char0, char1)) {
// Attributes are not additive, so clear all formatting
this.clearFormatting(packet.pts);
// According to the standard, mid-row codes
// should be replaced with spaces, so add one now
this[this.mode_](packet.pts, ' ');
this.column_++;
if ((char1 & 0xe) === 0xe) {
this.addFormatting(packet.pts, ['i']);
}
if ((char1 & 0x1) === 0x1) {
this.addFormatting(packet.pts, ['u']);
}
// Detect offset control codes and adjust cursor
} else if (this.isOffsetControlCode(char0, char1)) {
// Cursor position is set by indent PAC (see below) in 4-column
// increments, with an additional offset code of 1-3 to reach any
// of the 32 columns specified by CEA-608. So all we need to do
// here is increment the column cursor by the given offset.
this.column_ += (char1 & 0x03);
// Detect PACs (Preamble Address Codes)
} else if (this.isPAC(char0, char1)) {
// There's no logic for PAC -> row mapping, so we have to just
// find the row code in an array and use its index :(
var row = ROWS.indexOf(data & 0x1f20);
if (row !== this.row_) {
// formatting is only persistent for current row
this.clearFormatting(packet.pts);
this.row_ = row;
}
// All PACs can apply underline, so detect and apply
// (All odd-numbered second bytes set underline)
if ((char1 & 0x1) && (this.formatting_.indexOf('u') === -1)) {
this.addFormatting(packet.pts, ['u']);
}
if ((data & 0x10) === 0x10) {
// We've got an indent level code. Each successive even number
// increments the column cursor by 4, so we can get the desired
// column position by bit-shifting to the right (to get n/2)
// and multiplying by 4.
this.column_ = ((data & 0xe) >> 1) * 4;
}
if (this.isColorPAC(char1)) {
// it's a color code, though we only support white, which
// can be either normal or italicized. white italics can be
// either 0x4e or 0x6e depending on the row, so we just
// bitwise-and with 0xe to see if italics should be turned on
if ((char1 & 0xe) === 0xe) {
this.addFormatting(packet.pts, ['i']);
}
}
// We have a normal character in char0, and possibly one in char1
} else if (this.isNormalChar(char0)) {
if (char1 === 0x00) {
char1 = null;
}
text = getCharFromCode(char0);
text += getCharFromCode(char1);
this[this.mode_](packet.pts, text);
this.column_ += text.length;
} // finish data processing
};
};
Cea608Stream.prototype = new Stream();
// Trigger a cue point that captures the current state of the
// display buffer
Cea608Stream.prototype.flushDisplayed = function(pts) {
var content = this.displayed_
// remove spaces from the start and end of the string
.map(function(row) {
return row.trim();
})
// combine all text rows to display in one cue
.join('\n')
// and remove blank rows from the start and end, but not the middle
.replace(/^\n+|\n+$/g, '');
if (content.length) {
this.trigger('data', {
startPts: this.startPts_,
endPts: pts,
text: content,
stream: this.name_
});
}
};
/**
* Zero out the data, used for startup and on seek
*/
Cea608Stream.prototype.reset = function() {
this.mode_ = 'popOn';
// When in roll-up mode, the index of the last row that will
// actually display captions. If a caption is shifted to a row
// with a lower index than this, it is cleared from the display
// buffer
this.topRow_ = 0;
this.startPts_ = 0;
this.displayed_ = createDisplayBuffer();
this.nonDisplayed_ = createDisplayBuffer();
this.lastControlCode_ = null;
// Track row and column for proper line-breaking and spacing
this.column_ = 0;
this.row_ = BOTTOM_ROW;
// This variable holds currently-applied formatting
this.formatting_ = [];
};
/**
* Sets up control code and related constants for this instance
*/
Cea608Stream.prototype.setConstants = function() {
// The following attributes have these uses:
// ext_ : char0 for mid-row codes, and the base for extended
// chars (ext_+0, ext_+1, and ext_+2 are char0s for
// extended codes)
// control_: char0 for control codes, except byte-shifted to the
// left so that we can do this.control_ | CONTROL_CODE
// offset_: char0 for tab offset codes
//
// It's also worth noting that control codes, and _only_ control codes,
// differ between field 1 and field2. Field 2 control codes are always
// their field 1 value plus 1. That's why there's the "| field" on the
// control value.
if (this.dataChannel_ === 0) {
this.BASE_ = 0x10;
this.EXT_ = 0x11;
this.CONTROL_ = (0x14 | this.field_) << 8;
this.OFFSET_ = 0x17;
} else if (this.dataChannel_ === 1) {
this.BASE_ = 0x18;
this.EXT_ = 0x19;
this.CONTROL_ = (0x1c | this.field_) << 8;
this.OFFSET_ = 0x1f;
}
// Constants for the LSByte command codes recognized by Cea608Stream. This
// list is not exhaustive. For a more comprehensive listing and semantics see
// http://www.gpo.gov/fdsys/pkg/CFR-2010-title47-vol1/pdf/CFR-2010-title47-vol1-sec15-119.pdf
// Padding
this.PADDING_ = 0x0000;
// Pop-on Mode
this.RESUME_CAPTION_LOADING_ = this.CONTROL_ | 0x20;
this.END_OF_CAPTION_ = this.CONTROL_ | 0x2f;
// Roll-up Mode
this.ROLL_UP_2_ROWS_ = this.CONTROL_ | 0x25;
this.ROLL_UP_3_ROWS_ = this.CONTROL_ | 0x26;
this.ROLL_UP_4_ROWS_ = this.CONTROL_ | 0x27;
this.CARRIAGE_RETURN_ = this.CONTROL_ | 0x2d;
// paint-on mode (not supported)
this.RESUME_DIRECT_CAPTIONING_ = this.CONTROL_ | 0x29;
// Erasure
this.BACKSPACE_ = this.CONTROL_ | 0x21;
this.ERASE_DISPLAYED_MEMORY_ = this.CONTROL_ | 0x2c;
this.ERASE_NON_DISPLAYED_MEMORY_ = this.CONTROL_ | 0x2e;
};
/**
* Detects if the 2-byte packet data is a special character
*
* Special characters have a second byte in the range 0x30 to 0x3f,
* with the first byte being 0x11 (for data channel 1) or 0x19 (for
* data channel 2).
*
* @param {Integer} char0 The first byte
* @param {Integer} char1 The second byte
* @return {Boolean} Whether the 2 bytes are an special character
*/
Cea608Stream.prototype.isSpecialCharacter = function(char0, char1) {
return (char0 === this.EXT_ && char1 >= 0x30 && char1 <= 0x3f);
};
/**
* Detects if the 2-byte packet data is an extended character
*
* Extended characters have a second byte in the range 0x20 to 0x3f,
* with the first byte being 0x12 or 0x13 (for data channel 1) or
* 0x1a or 0x1b (for data channel 2).
*
* @param {Integer} char0 The first byte
* @param {Integer} char1 The second byte
* @return {Boolean} Whether the 2 bytes are an extended character
*/
Cea608Stream.prototype.isExtCharacter = function(char0, char1) {
return ((char0 === (this.EXT_ + 1) || char0 === (this.EXT_ + 2)) &&
(char1 >= 0x20 && char1 <= 0x3f));
};
/**
* Detects if the 2-byte packet is a mid-row code
*
* Mid-row codes have a second byte in the range 0x20 to 0x2f, with
* the first byte being 0x11 (for data channel 1) or 0x19 (for data
* channel 2).
*
* @param {Integer} char0 The first byte
* @param {Integer} char1 The second byte
* @return {Boolean} Whether the 2 bytes are a mid-row code
*/
Cea608Stream.prototype.isMidRowCode = function(char0, char1) {
return (char0 === this.EXT_ && (char1 >= 0x20 && char1 <= 0x2f));
};
/**
* Detects if the 2-byte packet is an offset control code
*
* Offset control codes have a second byte in the range 0x21 to 0x23,
* with the first byte being 0x17 (for data channel 1) or 0x1f (for
* data channel 2).
*
* @param {Integer} char0 The first byte
* @param {Integer} char1 The second byte
* @return {Boolean} Whether the 2 bytes are an offset control code
*/
Cea608Stream.prototype.isOffsetControlCode = function(char0, char1) {
return (char0 === this.OFFSET_ && (char1 >= 0x21 && char1 <= 0x23));
};
/**
* Detects if the 2-byte packet is a Preamble Address Code
*
* PACs have a first byte in the range 0x10 to 0x17 (for data channel 1)
* or 0x18 to 0x1f (for data channel 2), with the second byte in the
* range 0x40 to 0x7f.
*
* @param {Integer} char0 The first byte
* @param {Integer} char1 The second byte
* @return {Boolean} Whether the 2 bytes are a PAC
*/
Cea608Stream.prototype.isPAC = function(char0, char1) {
return (char0 >= this.BASE_ && char0 < (this.BASE_ + 8) &&
(char1 >= 0x40 && char1 <= 0x7f));
};
/**
* Detects if a packet's second byte is in the range of a PAC color code
*
* PAC color codes have the second byte be in the range 0x40 to 0x4f, or
* 0x60 to 0x6f.
*
* @param {Integer} char1 The second byte
* @return {Boolean} Whether the byte is a color PAC
*/
Cea608Stream.prototype.isColorPAC = function(char1) {
return ((char1 >= 0x40 && char1 <= 0x4f) || (char1 >= 0x60 && char1 <= 0x7f));
};
/**
* Detects if a single byte is in the range of a normal character
*
* Normal text bytes are in the range 0x20 to 0x7f.
*
* @param {Integer} char The byte
* @return {Boolean} Whether the byte is a normal character
*/
Cea608Stream.prototype.isNormalChar = function(char) {
return (char >= 0x20 && char <= 0x7f);
};
// Adds the opening HTML tag for the passed character to the caption text,
// and keeps track of it for later closing
Cea608Stream.prototype.addFormatting = function(pts, format) {
this.formatting_ = this.formatting_.concat(format);
var text = format.reduce(function(text, format) {
return text + '<' + format + '>';
}, '');
this[this.mode_](pts, text);
};
// Adds HTML closing tags for current formatting to caption text and
// clears remembered formatting
Cea608Stream.prototype.clearFormatting = function(pts) {
if (!this.formatting_.length) {
return;
}
var text = this.formatting_.reverse().reduce(function(text, format) {
return text + '</' + format + '>';
}, '');
this.formatting_ = [];
this[this.mode_](pts, text);
};
// Mode Implementations
Cea608Stream.prototype.popOn = function(pts, text) {
var baseRow = this.nonDisplayed_[this.row_];
// buffer characters
baseRow += text;
this.nonDisplayed_[this.row_] = baseRow;
};
Cea608Stream.prototype.rollUp = function(pts, text) {
var baseRow = this.displayed_[BOTTOM_ROW];
baseRow += text;
this.displayed_[BOTTOM_ROW] = baseRow;
};
Cea608Stream.prototype.shiftRowsUp_ = function() {
var i;
// clear out inactive rows
for (i = 0; i < this.topRow_; i++) {
this.displayed_[i] = '';
}
// shift displayed rows up
for (i = this.topRow_; i < BOTTOM_ROW; i++) {
this.displayed_[i] = this.displayed_[i + 1];
}
// clear out the bottom row
this.displayed_[BOTTOM_ROW] = '';
};
// paintOn mode is not implemented
Cea608Stream.prototype.paintOn = function() {};
// exports
module.exports = {
CaptionStream: CaptionStream,
Cea608Stream: Cea608Stream
};
},{"../utils/stream":15}],6:[function(require,module,exports){
/**
* mux.js
*
* Copyright (c) 2015 Brightcove
* All rights reserved.
*
* A stream-based mp2t to mp4 converter. This utility can be used to
* deliver mp4s to a SourceBuffer on platforms that support native
* Media Source Extensions.
*/
'use strict';
var Stream = require('../utils/stream.js'),
CaptionStream = require('./caption-stream'),
StreamTypes = require('./stream-types'),
TimestampRolloverStream = require('./timestamp-rollover-stream').TimestampRolloverStream;
var m2tsStreamTypes = require('./stream-types.js');
// object types
var TransportPacketStream, TransportParseStream, ElementaryStream;
// constants
var
MP2T_PACKET_LENGTH = 188, // bytes
SYNC_BYTE = 0x47;
/**
* Splits an incoming stream of binary data into MPEG-2 Transport
* Stream packets.
*/
TransportPacketStream = function() {
var
buffer = new Uint8Array(MP2T_PACKET_LENGTH),
bytesInBuffer = 0;
TransportPacketStream.prototype.init.call(this);
// Deliver new bytes to the stream.
this.push = function(bytes) {
var
startIndex = 0,
endIndex = MP2T_PACKET_LENGTH,
everything;
// If there are bytes remaining from the last segment, prepend them to the
// bytes that were pushed in
if (bytesInBuffer) {
everything = new Uint8Array(bytes.byteLength + bytesInBuffer);
everything.set(buffer.subarray(0, bytesInBuffer));
everything.set(bytes, bytesInBuffer);
bytesInBuffer = 0;
} else {
everything = bytes;
}
// While we have enough data for a packet
while (endIndex < everything.byteLength) {
// Look for a pair of start and end sync bytes in the data..
if (everything[startIndex] === SYNC_BYTE && everything[endIndex] === SYNC_BYTE) {
// We found a packet so emit it and jump one whole packet forward in
// the stream
this.trigger('data', everything.subarray(startIndex, endIndex));
startIndex += MP2T_PACKET_LENGTH;
endIndex += MP2T_PACKET_LENGTH;
continue;
}
// If we get here, we have somehow become de-synchronized and we need to step
// forward one byte at a time until we find a pair of sync bytes that denote
// a packet
startIndex++;
endIndex++;
}
// If there was some data left over at the end of the segment that couldn't
// possibly be a whole packet, keep it because it might be the start of a packet
// that continues in the next segment
if (startIndex < everything.byteLength) {
buffer.set(everything.subarray(startIndex), 0);
bytesInBuffer = everything.byteLength - startIndex;
}
};
this.flush = function() {
// If the buffer contains a whole packet when we are being flushed, emit it
// and empty the buffer. Otherwise hold onto the data because it may be
// important for decoding the next segment
if (bytesInBuffer === MP2T_PACKET_LENGTH && buffer[0] === SYNC_BYTE) {
this.trigger('data', buffer);
bytesInBuffer = 0;
}
this.trigger('done');
};
};
TransportPacketStream.prototype = new Stream();
/**
* Accepts an MP2T TransportPacketStream and emits data events with parsed
* forms of the individual transport stream packets.
*/
TransportParseStream = function() {
var parsePsi, parsePat, parsePmt, self;
TransportParseStream.prototype.init.call(this);
self = this;
this.packetsWaitingForPmt = [];
this.programMapTable = undefined;
parsePsi = function(payload, psi) {
var offset = 0;
// PSI packets may be split into multiple sections and those
// sections may be split into multiple packets. If a PSI
// section starts in this packet, the payload_unit_start_indicator
// will be true and the first byte of the payload will indicate
// the offset from the current position to the start of the
// section.
if (psi.payloadUnitStartIndicator) {
offset += payload[offset] + 1;
}
if (psi.type === 'pat') {
parsePat(payload.subarray(offset), psi);
} else {
parsePmt(payload.subarray(offset), psi);
}
};
parsePat = function(payload, pat) {
pat.section_number = payload[7]; // eslint-disable-line camelcase
pat.last_section_number = payload[8]; // eslint-disable-line camelcase
// skip the PSI header and parse the first PMT entry
self.pmtPid = (payload[10] & 0x1F) << 8 | payload[11];
pat.pmtPid = self.pmtPid;
};
/**
* Parse out the relevant fields of a Program Map Table (PMT).
* @param payload {Uint8Array} the PMT-specific portion of an MP2T
* packet. The first byte in this array should be the table_id
* field.
* @param pmt {object} the object that should be decorated with
* fields parsed from the PMT.
*/
parsePmt = function(payload, pmt) {
var sectionLength, tableEnd, programInfoLength, offset;
// PMTs can be sent ahead of the time when they should actually
// take effect. We don't believe this should ever be the case
// for HLS but we'll ignore "forward" PMT declarations if we see
// them. Future PMT declarations have the current_next_indicator
// set to zero.
if (!(payload[5] & 0x01)) {
return;
}
// overwrite any existing program map table
self.programMapTable = {
video: null,
audio: null,
'timed-metadata': {}
};
// the mapping table ends at the end of the current section
sectionLength = (payload[1] & 0x0f) << 8 | payload[2];
tableEnd = 3 + sectionLength - 4;
// to determine where the table is, we have to figure out how
// long the program info descriptors are
programInfoLength = (payload[10] & 0x0f) << 8 | payload[11];
// advance the offset to the first entry in the mapping table
offset = 12 + programInfoLength;
while (offset < tableEnd) {
var streamType = payload[offset];
var pid = (payload[offset + 1] & 0x1F) << 8 | payload[offset + 2];
// only map a single elementary_pid for audio and video stream types
// TODO: should this be done for metadata too? for now maintain behavior of
// multiple metadata streams
if (streamType === StreamTypes.H264_STREAM_TYPE &&
self.programMapTable.video === null) {
self.programMapTable.video = pid;
} else if (streamType === StreamTypes.ADTS_STREAM_TYPE &&
self.programMapTable.audio === null) {
self.programMapTable.audio = pid;
} else if (streamType === StreamTypes.METADATA_STREAM_TYPE) {
// map pid to stream type for metadata streams
self.programMapTable['timed-metadata'][pid] = streamType;
}
// move to the next table entry
// skip past the elementary stream descriptors, if present
offset += ((payload[offset + 3] & 0x0F) << 8 | payload[offset + 4]) + 5;
}
// record the map on the packet as well
pmt.programMapTable = self.programMapTable;
};
/**
* Deliver a new MP2T packet to the stream.
*/
this.push = function(packet) {
var
result = {},
offset = 4;
result.payloadUnitStartIndicator = !!(packet[1] & 0x40);
// pid is a 13-bit field starting at the last bit of packet[1]
result.pid = packet[1] & 0x1f;
result.pid <<= 8;
result.pid |= packet[2];
// if an adaption field is present, its length is specified by the
// fifth byte of the TS packet header. The adaptation field is
// used to add stuffing to PES packets that don't fill a complete
// TS packet, and to specify some forms of timing and control data
// that we do not currently use.
if (((packet[3] & 0x30) >>> 4) > 0x01) {
offset += packet[offset] + 1;
}
// parse the rest of the packet based on the type
if (result.pid === 0) {
result.type = 'pat';
parsePsi(packet.subarray(offset), result);
this.trigger('data', result);
} else if (result.pid === this.pmtPid) {
result.type = 'pmt';
parsePsi(packet.subarray(offset), result);
this.trigger('data', result);
// if there are any packets waiting for a PMT to be found, process them now
while (this.packetsWaitingForPmt.length) {
this.processPes_.apply(this, this.packetsWaitingForPmt.shift());
}
} else if (this.programMapTable === undefined) {
// When we have not seen a PMT yet, defer further processing of
// PES packets until one has been parsed
this.packetsWaitingForPmt.push([packet, offset, result]);
} else {
this.processPes_(packet, offset, result);
}
};
this.processPes_ = function(packet, offset, result) {
// set the appropriate stream type
if (result.pid === this.programMapTable.video) {
result.streamType = StreamTypes.H264_STREAM_TYPE;
} else if (result.pid === this.programMapTable.audio) {
result.streamType = StreamTypes.ADTS_STREAM_TYPE;
} else {
// if not video or audio, it is timed-metadata or unknown
// if unknown, streamType will be undefined
result.streamType = this.programMapTable['timed-metadata'][result.pid];
}
result.type = 'pes';
result.data = packet.subarray(offset);
this.trigger('data', result);
};
};
TransportParseStream.prototype = new Stream();
TransportParseStream.STREAM_TYPES = {
h264: 0x1b,
adts: 0x0f
};
/**
* Reconsistutes program elementary stream (PES) packets from parsed
* transport stream packets. That is, if you pipe an
* mp2t.TransportParseStream into a mp2t.ElementaryStream, the output
* events will be events which capture the bytes for individual PES
* packets plus relevant metadata that has been extracted from the
* container.
*/
ElementaryStream = function() {
var
self = this,
// PES packet fragments
video = {
data: [],
size: 0
},
audio = {
data: [],
size: 0
},
timedMetadata = {
data: [],
size: 0
},
parsePes = function(payload, pes) {
var ptsDtsFlags;
// get the packet length, this will be 0 for video
pes.packetLength = 6 + ((payload[4] << 8) | payload[5]);
// find out if this packets starts a new keyframe
pes.dataAlignmentIndicator = (payload[6] & 0x04) !== 0;
// PES packets may be annotated with a PTS value, or a PTS value
// and a DTS value. Determine what combination of values is
// available to work with.
ptsDtsFlags = payload[7];
// PTS and DTS are normally stored as a 33-bit number. Javascript
// performs all bitwise operations on 32-bit integers but javascript
// supports a much greater range (52-bits) of integer using standard
// mathematical operations.
// We construct a 31-bit value using bitwise operators over the 31
// most significant bits and then multiply by 4 (equal to a left-shift
// of 2) before we add the final 2 least significant bits of the
// timestamp (equal to an OR.)
if (ptsDtsFlags & 0xC0) {
// the PTS and DTS are not written out directly. For information
// on how they are encoded, see
// http://dvd.sourceforge.net/dvdinfo/pes-hdr.html
pes.pts = (payload[9] & 0x0E) << 27 |
(payload[10] & 0xFF) << 20 |
(payload[11] & 0xFE) << 12 |
(payload[12] & 0xFF) << 5 |
(payload[13] & 0xFE) >>> 3;
pes.pts *= 4; // Left shift by 2
pes.pts += (payload[13] & 0x06) >>> 1; // OR by the two LSBs
pes.dts = pes.pts;
if (ptsDtsFlags & 0x40) {
pes.dts = (payload[14] & 0x0E) << 27 |
(payload[15] & 0xFF) << 20 |
(payload[16] & 0xFE) << 12 |
(payload[17] & 0xFF) << 5 |
(payload[18] & 0xFE) >>> 3;
pes.dts *= 4; // Left shift by 2
pes.dts += (payload[18] & 0x06) >>> 1; // OR by the two LSBs
}
}
// the data section starts immediately after the PES header.
// pes_header_data_length specifies the number of header bytes
// that follow the last byte of the field.
pes.data = payload.subarray(9 + payload[8]);
},
flushStream = function(stream, type, forceFlush) {
var
packetData = new Uint8Array(stream.size),
event = {
type: type
},
i = 0,
offset = 0,
packetFlushable = false,
fragment;
// do nothing if there is not enough buffered data for a complete
// PES header
if (!stream.data.length || stream.size < 9) {
return;
}
event.trackId = stream.data[0].pid;
// reassemble the packet
for (i = 0; i < stream.data.length; i++) {
fragment = stream.data[i];
packetData.set(fragment.data, offset);
offset += fragment.data.byteLength;
}
// parse assembled packet's PES header
parsePes(packetData, event);
// non-video PES packets MUST have a non-zero PES_packet_length
// check that there is enough stream data to fill the packet
packetFlushable = type === 'video' || event.packetLength <= stream.size;
// flush pending packets if the conditions are right
if (forceFlush || packetFlushable) {
stream.size = 0;
stream.data.length = 0;
}
// only emit packets that are complete. this is to avoid assembling
// incomplete PES packets due to poor segmentation
if (packetFlushable) {
self.trigger('data', event);
}
};
ElementaryStream.prototype.init.call(this);
this.push = function(data) {
({
pat: function() {
// we have to wait for the PMT to arrive as well before we
// have any meaningful metadata
},
pes: function() {
var stream, streamType;
switch (data.streamType) {
case StreamTypes.H264_STREAM_TYPE:
case m2tsStreamTypes.H264_STREAM_TYPE:
stream = video;
streamType = 'video';
break;
case StreamTypes.ADTS_STREAM_TYPE:
stream = audio;
streamType = 'audio';
break;
case StreamTypes.METADATA_STREAM_TYPE:
stream = timedMetadata;
streamType = 'timed-metadata';
break;
default:
// ignore unknown stream types
return;
}
// if a new packet is starting, we can flush the completed
// packet
if (data.payloadUnitStartIndicator) {
flushStream(stream, streamType, true);
}
// buffer this fragment until we are sure we've received the
// complete payload
stream.data.push(data);
stream.size += data.data.byteLength;
},
pmt: function() {
var
event = {
type: 'metadata',
tracks: []
},
programMapTable = data.programMapTable;
// translate audio and video streams to tracks
if (programMapTable.video !== null) {
event.tracks.push({
timelineStartInfo: {
baseMediaDecodeTime: 0
},
id: +programMapTable.video,
codec: 'avc',
type: 'video'
});
}
if (programMapTable.audio !== null) {
event.tracks.push({
timelineStartInfo: {
baseMediaDecodeTime: 0
},
id: +programMapTable.audio,
codec: 'adts',
type: 'audio'
});
}
self.trigger('data', event);
}
})[data.type]();
};
/**
* Flush any remaining input. Video PES packets may be of variable
* length. Normally, the start of a new video packet can trigger the
* finalization of the previous packet. That is not possible if no
* more video is forthcoming, however. In that case, some other
* mechanism (like the end of the file) has to be employed. When it is
* clear that no additional data is forthcoming, calling this method
* will flush the buffered packets.
*/
this.flush = function() {
// !!THIS ORDER IS IMPORTANT!!
// video first then audio
flushStream(video, 'video');
flushStream(audio, 'audio');
flushStream(timedMetadata, 'timed-metadata');
this.trigger('done');
};
};
ElementaryStream.prototype = new Stream();
var m2ts = {
PAT_PID: 0x0000,
MP2T_PACKET_LENGTH: MP2T_PACKET_LENGTH,
TransportPacketStream: TransportPacketStream,
TransportParseStream: TransportParseStream,
ElementaryStream: ElementaryStream,
TimestampRolloverStream: TimestampRolloverStream,
CaptionStream: CaptionStream.CaptionStream,
Cea608Stream: CaptionStream.Cea608Stream,
MetadataStream: require('./metadata-stream')
};
for (var type in StreamTypes) {
if (StreamTypes.hasOwnProperty(type)) {
m2ts[type] = StreamTypes[type];
}
}
module.exports = m2ts;
},{"../utils/stream.js":15,"./caption-stream":5,"./metadata-stream":7,"./stream-types":8,"./stream-types.js":8,"./timestamp-rollover-stream":9}],7:[function(require,module,exports){
/**
* Accepts program elementary stream (PES) data events and parses out
* ID3 metadata from them, if present.
* @see http://id3.org/id3v2.3.0
*/
'use strict';
var
Stream = require('../utils/stream'),
StreamTypes = require('./stream-types'),
// return a percent-encoded representation of the specified byte range
// @see http://en.wikipedia.org/wiki/Percent-encoding
percentEncode = function(bytes, start, end) {
var i, result = '';
for (i = start; i < end; i++) {
result += '%' + ('00' + bytes[i].toString(16)).slice(-2);
}
return result;
},
// return the string representation of the specified byte range,
// interpreted as UTf-8.
parseUtf8 = function(bytes, start, end) {
return decodeURIComponent(percentEncode(bytes, start, end));
},
// return the string representation of the specified byte range,
// interpreted as ISO-8859-1.
parseIso88591 = function(bytes, start, end) {
return unescape(percentEncode(bytes, start, end)); // jshint ignore:line
},
parseSyncSafeInteger = function(data) {
return (data[0] << 21) |
(data[1] << 14) |
(data[2] << 7) |
(data[3]);
},
tagParsers = {
TXXX: function(tag) {
var i;
if (tag.data[0] !== 3) {
// ignore frames with unrecognized character encodings
return;
}
for (i = 1; i < tag.data.length; i++) {
if (tag.data[i] === 0) {
// parse the text fields
tag.description = parseUtf8(tag.data, 1, i);
// do not include the null terminator in the tag value
tag.value = parseUtf8(tag.data, i + 1, tag.data.length).replace(/\0*$/, '');
break;
}
}
tag.data = tag.value;
},
WXXX: function(tag) {
var i;
if (tag.data[0] !== 3) {
// ignore frames with unrecognized character encodings
return;
}
for (i = 1; i < tag.data.length; i++) {
if (tag.data[i] === 0) {
// parse the description and URL fields
tag.description = parseUtf8(tag.data, 1, i);
tag.url = parseUtf8(tag.data, i + 1, tag.data.length);
break;
}
}
},
PRIV: function(tag) {
var i;
for (i = 0; i < tag.data.length; i++) {
if (tag.data[i] === 0) {
// parse the description and URL fields
tag.owner = parseIso88591(tag.data, 0, i);
break;
}
}
tag.privateData = tag.data.subarray(i + 1);
tag.data = tag.privateData;
}
},
MetadataStream;
MetadataStream = function(options) {
var
settings = {
debug: !!(options && options.debug),
// the bytes of the program-level descriptor field in MP2T
// see ISO/IEC 13818-1:2013 (E), section 2.6 "Program and
// program element descriptors"
descriptor: options && options.descriptor
},
// the total size in bytes of the ID3 tag being parsed
tagSize = 0,
// tag data that is not complete enough to be parsed
buffer = [],
// the total number of bytes currently in the buffer
bufferSize = 0,
i;
MetadataStream.prototype.init.call(this);
// calculate the text track in-band metadata track dispatch type
// https://html.spec.whatwg.org/multipage/embedded-content.html#steps-to-expose-a-media-resource-specific-text-track
this.dispatchType = StreamTypes.METADATA_STREAM_TYPE.toString(16);
if (settings.descriptor) {
for (i = 0; i < settings.descriptor.length; i++) {
this.dispatchType += ('00' + settings.descriptor[i].toString(16)).slice(-2);
}
}
this.push = function(chunk) {
var tag, frameStart, frameSize, frame, i, frameHeader;
if (chunk.type !== 'timed-metadata') {
return;
}
// if data_alignment_indicator is set in the PES header,
// we must have the start of a new ID3 tag. Assume anything
// remaining in the buffer was malformed and throw it out
if (chunk.dataAlignmentIndicator) {
bufferSize = 0;
buffer.length = 0;
}
// ignore events that don't look like ID3 data
if (buffer.length === 0 &&
(chunk.data.length < 10 ||
chunk.data[0] !== 'I'.charCodeAt(0) ||
chunk.data[1] !== 'D'.charCodeAt(0) ||
chunk.data[2] !== '3'.charCodeAt(0))) {
if (settings.debug) {
// eslint-disable-next-line no-console
console.log('Skipping unrecognized metadata packet');
}
return;
}
// add this chunk to the data we've collected so far
buffer.push(chunk);
bufferSize += chunk.data.byteLength;
// grab the size of the entire frame from the ID3 header
if (buffer.length === 1) {
// the frame size is transmitted as a 28-bit integer in the
// last four bytes of the ID3 header.
// The most significant bit of each byte is dropped and the
// results concatenated to recover the actual value.
tagSize = parseSyncSafeInteger(chunk.data.subarray(6, 10));
// ID3 reports the tag size excluding the header but it's more
// convenient for our comparisons to include it
tagSize += 10;
}
// if the entire frame has not arrived, wait for more data
if (bufferSize < tagSize) {
return;
}
// collect the entire frame so it can be parsed
tag = {
data: new Uint8Array(tagSize),
frames: [],
pts: buffer[0].pts,
dts: buffer[0].dts
};
for (i = 0; i < tagSize;) {
tag.data.set(buffer[0].data.subarray(0, tagSize - i), i);
i += buffer[0].data.byteLength;
bufferSize -= buffer[0].data.byteLength;
buffer.shift();
}
// find the start of the first frame and the end of the tag
frameStart = 10;
if (tag.data[5] & 0x40) {
// advance the frame start past the extended header
frameStart += 4; // header size field
frameStart += parseSyncSafeInteger(tag.data.subarray(10, 14));
// clip any padding off the end
tagSize -= parseSyncSafeInteger(tag.data.subarray(16, 20));
}
// parse one or more ID3 frames
// http://id3.org/id3v2.3.0#ID3v2_frame_overview
do {
// determine the number of bytes in this frame
frameSize = parseSyncSafeInteger(tag.data.subarray(frameStart + 4, frameStart + 8));
if (frameSize < 1) {
// eslint-disable-next-line no-console
return console.log('Malformed ID3 frame encountered. Skipping metadata parsing.');
}
frameHeader = String.fromCharCode(tag.data[frameStart],
tag.data[frameStart + 1],
tag.data[frameStart + 2],
tag.data[frameStart + 3]);
frame = {
id: frameHeader,
data: tag.data.subarray(frameStart + 10, frameStart + frameSize + 10)
};
frame.key = frame.id;
if (tagParsers[frame.id]) {
tagParsers[frame.id](frame);
// handle the special PRIV frame used to indicate the start
// time for raw AAC data
if (frame.owner === 'com.apple.streaming.transportStreamTimestamp') {
var
d = frame.data,
size = ((d[3] & 0x01) << 30) |
(d[4] << 22) |
(d[5] << 14) |
(d[6] << 6) |
(d[7] >>> 2);
size *= 4;
size += d[7] & 0x03;
frame.timeStamp = size;
// in raw AAC, all subsequent data will be timestamped based
// on the value of this frame
// we couldn't have known the appropriate pts and dts before
// parsing this ID3 tag so set those values now
if (tag.pts === undefined && tag.dts === undefined) {
tag.pts = frame.timeStamp;
tag.dts = frame.timeStamp;
}
this.trigger('timestamp', frame);
}
}
tag.frames.push(frame);
frameStart += 10; // advance past the frame header
frameStart += frameSize; // advance past the frame body
} while (frameStart < tagSize);
this.trigger('data', tag);
};
};
MetadataStream.prototype = new Stream();
module.exports = MetadataStream;
},{"../utils/stream":15,"./stream-types":8}],8:[function(require,module,exports){
'use strict';
module.exports = {
H264_STREAM_TYPE: 0x1B,
ADTS_STREAM_TYPE: 0x0F,
METADATA_STREAM_TYPE: 0x15
};
},{}],9:[function(require,module,exports){
/**
* mux.js
*
* Copyright (c) 2016 Brightcove
* All rights reserved.
*
* Accepts program elementary stream (PES) data events and corrects
* decode and presentation time stamps to account for a rollover
* of the 33 bit value.
*/
'use strict';
var Stream = require('../utils/stream');
var MAX_TS = 8589934592;
var RO_THRESH = 4294967296;
var handleRollover = function(value, reference) {
var direction = 1;
if (value > reference) {
// If the current timestamp value is greater than our reference timestamp and we detect a
// timestamp rollover, this means the roll over is happening in the opposite direction.
// Example scenario: Enter a long stream/video just after a rollover occurred. The reference
// point will be set to a small number, e.g. 1. The user then seeks backwards over the
// rollover point. In loading this segment, the timestamp values will be very large,
// e.g. 2^33 - 1. Since this comes before the data we loaded previously, we want to adjust
// the time stamp to be `value - 2^33`.
direction = -1;
}
// Note: A seek forwards or back that is greater than the RO_THRESH (2^32, ~13 hours) will
// cause an incorrect adjustment.
while (Math.abs(reference - value) > RO_THRESH) {
value += (direction * MAX_TS);
}
return value;
};
var TimestampRolloverStream = function(type) {
var lastDTS, referenceDTS;
TimestampRolloverStream.prototype.init.call(this);
this.type_ = type;
this.push = function(data) {
if (data.type !== this.type_) {
return;
}
if (referenceDTS === undefined) {
referenceDTS = data.dts;
}
data.dts = handleRollover(data.dts, referenceDTS);
data.pts = handleRollover(data.pts, referenceDTS);
lastDTS = data.dts;
this.trigger('data', data);
};
this.flush = function() {
referenceDTS = lastDTS;
this.trigger('done');
};
this.discontinuity = function() {
referenceDTS = void 0;
lastDTS = void 0;
};
};
TimestampRolloverStream.prototype = new Stream();
module.exports = {
TimestampRolloverStream: TimestampRolloverStream,
handleRollover: handleRollover
};
},{"../utils/stream":15}],10:[function(require,module,exports){
module.exports = {
generator: require('./mp4-generator'),
Transmuxer: require('./transmuxer').Transmuxer,
AudioSegmentStream: require('./transmuxer').AudioSegmentStream,
VideoSegmentStream: require('./transmuxer').VideoSegmentStream
};
},{"./mp4-generator":11,"./transmuxer":12}],11:[function(require,module,exports){
/**
* mux.js
*
* Copyright (c) 2015 Brightcove
* All rights reserved.
*
* Functions that generate fragmented MP4s suitable for use with Media
* Source Extensions.
*/
'use strict';
var UINT32_MAX = Math.pow(2, 32) - 1;
var box, dinf, esds, ftyp, mdat, mfhd, minf, moof, moov, mvex, mvhd,
trak, tkhd, mdia, mdhd, hdlr, sdtp, stbl, stsd, traf, trex,
trun, types, MAJOR_BRAND, MINOR_VERSION, AVC1_BRAND, VIDEO_HDLR,
AUDIO_HDLR, HDLR_TYPES, VMHD, SMHD, DREF, STCO, STSC, STSZ, STTS;
// pre-calculate constants
(function() {
var i;
types = {
avc1: [], // codingname
avcC: [],
btrt: [],
dinf: [],
dref: [],
esds: [],
ftyp: [],
hdlr: [],
mdat: [],
mdhd: [],
mdia: [],
mfhd: [],
minf: [],
moof: [],
moov: [],
mp4a: [], // codingname
mvex: [],
mvhd: [],
sdtp: [],
smhd: [],
stbl: [],
stco: [],
stsc: [],
stsd: [],
stsz: [],
stts: [],
styp: [],
tfdt: [],
tfhd: [],
traf: [],
trak: [],
trun: [],
trex: [],
tkhd: [],
vmhd: []
};
// In environments where Uint8Array is undefined (e.g., IE8), skip set up so that we
// don't throw an error
if (typeof Uint8Array === 'undefined') {
return;
}
for (i in types) {
if (types.hasOwnProperty(i)) {
types[i] = [
i.charCodeAt(0),
i.charCodeAt(1),
i.charCodeAt(2),
i.charCodeAt(3)
];
}
}
MAJOR_BRAND = new Uint8Array([
'i'.charCodeAt(0),
's'.charCodeAt(0),
'o'.charCodeAt(0),
'm'.charCodeAt(0)
]);
AVC1_BRAND = new Uint8Array([
'a'.charCodeAt(0),
'v'.charCodeAt(0),
'c'.charCodeAt(0),
'1'.charCodeAt(0)
]);
MINOR_VERSION = new Uint8Array([0, 0, 0, 1]);
VIDEO_HDLR = new Uint8Array([
0x00, // version 0
0x00, 0x00, 0x00, // flags
0x00, 0x00, 0x00, 0x00, // pre_defined
0x76, 0x69, 0x64, 0x65, // handler_type: 'vide'
0x00, 0x00, 0x00, 0x00, // reserved
0x00, 0x00, 0x00, 0x00, // reserved
0x00, 0x00, 0x00, 0x00, // reserved
0x56, 0x69, 0x64, 0x65,
0x6f, 0x48, 0x61, 0x6e,
0x64, 0x6c, 0x65, 0x72, 0x00 // name: 'VideoHandler'
]);
AUDIO_HDLR = new Uint8Array([
0x00, // version 0
0x00, 0x00, 0x00, // flags
0x00, 0x00, 0x00, 0x00, // pre_defined
0x73, 0x6f, 0x75, 0x6e, // handler_type: 'soun'
0x00, 0x00, 0x00, 0x00, // reserved
0x00, 0x00, 0x00, 0x00, // reserved
0x00, 0x00, 0x00, 0x00, // reserved
0x53, 0x6f, 0x75, 0x6e,
0x64, 0x48, 0x61, 0x6e,
0x64, 0x6c, 0x65, 0x72, 0x00 // name: 'SoundHandler'
]);
HDLR_TYPES = {
video: VIDEO_HDLR,
audio: AUDIO_HDLR
};
DREF = new Uint8Array([
0x00, // version 0
0x00, 0x00, 0x00, // flags
0x00, 0x00, 0x00, 0x01, // entry_count
0x00, 0x00, 0x00, 0x0c, // entry_size
0x75, 0x72, 0x6c, 0x20, // 'url' type
0x00, // version 0
0x00, 0x00, 0x01 // entry_flags
]);
SMHD = new Uint8Array([
0x00, // version
0x00, 0x00, 0x00, // flags
0x00, 0x00, // balance, 0 means centered
0x00, 0x00 // reserved
]);
STCO = new Uint8Array([
0x00, // version
0x00, 0x00, 0x00, // flags
0x00, 0x00, 0x00, 0x00 // entry_count
]);
STSC = STCO;
STSZ = new Uint8Array([
0x00, // version
0x00, 0x00, 0x00, // flags
0x00, 0x00, 0x00, 0x00, // sample_size
0x00, 0x00, 0x00, 0x00 // sample_count
]);
STTS = STCO;
VMHD = new Uint8Array([
0x00, // version
0x00, 0x00, 0x01, // flags
0x00, 0x00, // graphicsmode
0x00, 0x00,
0x00, 0x00,
0x00, 0x00 // opcolor
]);
}());
box = function(type) {
var
payload = [],
size = 0,
i,
result,
view;
for (i = 1; i < arguments.length; i++) {
payload.push(arguments[i]);
}
i = payload.length;
// calculate the total size we need to allocate
while (i--) {
size += payload[i].byteLength;
}
result = new Uint8Array(size + 8);
view = new DataView(result.buffer, result.byteOffset, result.byteLength);
view.setUint32(0, result.byteLength);
result.set(type, 4);
// copy the payload into the result
for (i = 0, size = 8; i < payload.length; i++) {
result.set(payload[i], size);
size += payload[i].byteLength;
}
return result;
};
dinf = function() {
return box(types.dinf, box(types.dref, DREF));
};
esds = function(track) {
return box(types.esds, new Uint8Array([
0x00, // version
0x00, 0x00, 0x00, // flags
// ES_Descriptor
0x03, // tag, ES_DescrTag
0x19, // length
0x00, 0x00, // ES_ID
0x00, // streamDependenceFlag, URL_flag, reserved, streamPriority
// DecoderConfigDescriptor
0x04, // tag, DecoderConfigDescrTag
0x11, // length
0x40, // object type
0x15, // streamType
0x00, 0x06, 0x00, // bufferSizeDB
0x00, 0x00, 0xda, 0xc0, // maxBitrate
0x00, 0x00, 0xda, 0xc0, // avgBitrate
// DecoderSpecificInfo
0x05, // tag, DecoderSpecificInfoTag
0x02, // length
// ISO/IEC 14496-3, AudioSpecificConfig
// for samplingFrequencyIndex see ISO/IEC 13818-7:2006, 8.1.3.2.2, Table 35
(track.audioobjecttype << 3) | (track.samplingfrequencyindex >>> 1),
(track.samplingfrequencyindex << 7) | (track.channelcount << 3),
0x06, 0x01, 0x02 // GASpecificConfig
]));
};
ftyp = function() {
return box(types.ftyp, MAJOR_BRAND, MINOR_VERSION, MAJOR_BRAND, AVC1_BRAND);
};
hdlr = function(type) {
return box(types.hdlr, HDLR_TYPES[type]);
};
mdat = function(data) {
return box(types.mdat, data);
};
mdhd = function(track) {
var result = new Uint8Array([
0x00, // version 0
0x00, 0x00, 0x00, // flags
0x00, 0x00, 0x00, 0x02, // creation_time
0x00, 0x00, 0x00, 0x03, // modification_time
0x00, 0x01, 0x5f, 0x90, // timescale, 90,000 "ticks" per second
(track.duration >>> 24) & 0xFF,
(track.duration >>> 16) & 0xFF,
(track.duration >>> 8) & 0xFF,
track.duration & 0xFF, // duration
0x55, 0xc4, // 'und' language (undetermined)
0x00, 0x00
]);
// Use the sample rate from the track metadata, when it is
// defined. The sample rate can be parsed out of an ADTS header, for
// instance.
if (track.samplerate) {
result[12] = (track.samplerate >>> 24) & 0xFF;
result[13] = (track.samplerate >>> 16) & 0xFF;
result[14] = (track.samplerate >>> 8) & 0xFF;
result[15] = (track.samplerate) & 0xFF;
}
return box(types.mdhd, result);
};
mdia = function(track) {
return box(types.mdia, mdhd(track), hdlr(track.type), minf(track));
};
mfhd = function(sequenceNumber) {
return box(types.mfhd, new Uint8Array([
0x00,
0x00, 0x00, 0x00, // flags
(sequenceNumber & 0xFF000000) >> 24,
(sequenceNumber & 0xFF0000) >> 16,
(sequenceNumber & 0xFF00) >> 8,
sequenceNumber & 0xFF // sequence_number
]));
};
minf = function(track) {
return box(types.minf,
track.type === 'video' ? box(types.vmhd, VMHD) : box(types.smhd, SMHD),
dinf(),
stbl(track));
};
moof = function(sequenceNumber, tracks) {
var
trackFragments = [],
i = tracks.length;
// build traf boxes for each track fragment
while (i--) {
trackFragments[i] = traf(tracks[i]);
}
return box.apply(null, [
types.moof,
mfhd(sequenceNumber)
].concat(trackFragments));
};
/**
* Returns a movie box.
* @param tracks {array} the tracks associated with this movie
* @see ISO/IEC 14496-12:2012(E), section 8.2.1
*/
moov = function(tracks) {
var
i = tracks.length,
boxes = [];
while (i--) {
boxes[i] = trak(tracks[i]);
}
return box.apply(null, [types.moov, mvhd(0xffffffff)].concat(boxes).concat(mvex(tracks)));
};
mvex = function(tracks) {
var
i = tracks.length,
boxes = [];
while (i--) {
boxes[i] = trex(tracks[i]);
}
return box.apply(null, [types.mvex].concat(boxes));
};
mvhd = function(duration) {
var
bytes = new Uint8Array([
0x00, // version 0
0x00, 0x00, 0x00, // flags
0x00, 0x00, 0x00, 0x01, // creation_time
0x00, 0x00, 0x00, 0x02, // modification_time
0x00, 0x01, 0x5f, 0x90, // timescale, 90,000 "ticks" per second
(duration & 0xFF000000) >> 24,
(duration & 0xFF0000) >> 16,
(duration & 0xFF00) >> 8,
duration & 0xFF, // duration
0x00, 0x01, 0x00, 0x00, // 1.0 rate
0x01, 0x00, // 1.0 volume
0x00, 0x00, // reserved
0x00, 0x00, 0x00, 0x00, // reserved
0x00, 0x00, 0x00, 0x00, // reserved
0x00, 0x01, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x01, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x40, 0x00, 0x00, 0x00, // transformation: unity matrix
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, // pre_defined
0xff, 0xff, 0xff, 0xff // next_track_ID
]);
return box(types.mvhd, bytes);
};
sdtp = function(track) {
var
samples = track.samples || [],
bytes = new Uint8Array(4 + samples.length),
flags,
i;
// leave the full box header (4 bytes) all zero
// write the sample table
for (i = 0; i < samples.length; i++) {
flags = samples[i].flags;
bytes[i + 4] = (flags.dependsOn << 4) |
(flags.isDependedOn << 2) |
(flags.hasRedundancy);
}
return box(types.sdtp,
bytes);
};
stbl = function(track) {
return box(types.stbl,
stsd(track),
box(types.stts, STTS),
box(types.stsc, STSC),
box(types.stsz, STSZ),
box(types.stco, STCO));
};
(function() {
var videoSample, audioSample;
stsd = function(track) {
return box(types.stsd, new Uint8Array([
0x00, // version 0
0x00, 0x00, 0x00, // flags
0x00, 0x00, 0x00, 0x01
]), track.type === 'video' ? videoSample(track) : audioSample(track));
};
videoSample = function(track) {
var
sps = track.sps || [],
pps = track.pps || [],
sequenceParameterSets = [],
pictureParameterSets = [],
i;
// assemble the SPSs
for (i = 0; i < sps.length; i++) {
sequenceParameterSets.push((sps[i].byteLength & 0xFF00) >>> 8);
sequenceParameterSets.push((sps[i].byteLength & 0xFF)); // sequenceParameterSetLength
sequenceParameterSets = sequenceParameterSets.concat(Array.prototype.slice.call(sps[i])); // SPS
}
// assemble the PPSs
for (i = 0; i < pps.length; i++) {
pictureParameterSets.push((pps[i].byteLength & 0xFF00) >>> 8);
pictureParameterSets.push((pps[i].byteLength & 0xFF));
pictureParameterSets = pictureParameterSets.concat(Array.prototype.slice.call(pps[i]));
}
return box(types.avc1, new Uint8Array([
0x00, 0x00, 0x00,
0x00, 0x00, 0x00, // reserved
0x00, 0x01, // data_reference_index
0x00, 0x00, // pre_defined
0x00, 0x00, // reserved
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, // pre_defined
(track.width & 0xff00) >> 8,
track.width & 0xff, // width
(track.height & 0xff00) >> 8,
track.height & 0xff, // height
0x00, 0x48, 0x00, 0x00, // horizresolution
0x00, 0x48, 0x00, 0x00, // vertresolution
0x00, 0x00, 0x00, 0x00, // reserved
0x00, 0x01, // frame_count
0x13,
0x76, 0x69, 0x64, 0x65,
0x6f, 0x6a, 0x73, 0x2d,
0x63, 0x6f, 0x6e, 0x74,
0x72, 0x69, 0x62, 0x2d,
0x68, 0x6c, 0x73, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, // compressorname
0x00, 0x18, // depth = 24
0x11, 0x11 // pre_defined = -1
]), box(types.avcC, new Uint8Array([
0x01, // configurationVersion
track.profileIdc, // AVCProfileIndication
track.profileCompatibility, // profile_compatibility
track.levelIdc, // AVCLevelIndication
0xff // lengthSizeMinusOne, hard-coded to 4 bytes
].concat([
sps.length // numOfSequenceParameterSets
]).concat(sequenceParameterSets).concat([
pps.length // numOfPictureParameterSets
]).concat(pictureParameterSets))), // "PPS"
box(types.btrt, new Uint8Array([
0x00, 0x1c, 0x9c, 0x80, // bufferSizeDB
0x00, 0x2d, 0xc6, 0xc0, // maxBitrate
0x00, 0x2d, 0xc6, 0xc0
])) // avgBitrate
);
};
audioSample = function(track) {
return box(types.mp4a, new Uint8Array([
// SampleEntry, ISO/IEC 14496-12
0x00, 0x00, 0x00,
0x00, 0x00, 0x00, // reserved
0x00, 0x01, // data_reference_index
// AudioSampleEntry, ISO/IEC 14496-12
0x00, 0x00, 0x00, 0x00, // reserved
0x00, 0x00, 0x00, 0x00, // reserved
(track.channelcount & 0xff00) >> 8,
(track.channelcount & 0xff), // channelcount
(track.samplesize & 0xff00) >> 8,
(track.samplesize & 0xff), // samplesize
0x00, 0x00, // pre_defined
0x00, 0x00, // reserved
(track.samplerate & 0xff00) >> 8,
(track.samplerate & 0xff),
0x00, 0x00 // samplerate, 16.16
// MP4AudioSampleEntry, ISO/IEC 14496-14
]), esds(track));
};
}());
tkhd = function(track) {
var result = new Uint8Array([
0x00, // version 0
0x00, 0x00, 0x07, // flags
0x00, 0x00, 0x00, 0x00, // creation_time
0x00, 0x00, 0x00, 0x00, // modification_time
(track.id & 0xFF000000) >> 24,
(track.id & 0xFF0000) >> 16,
(track.id & 0xFF00) >> 8,
track.id & 0xFF, // track_ID
0x00, 0x00, 0x00, 0x00, // reserved
(track.duration & 0xFF000000) >> 24,
(track.duration & 0xFF0000) >> 16,
(track.duration & 0xFF00) >> 8,
track.duration & 0xFF, // duration
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, // reserved
0x00, 0x00, // layer
0x00, 0x00, // alternate_group
0x01, 0x00, // non-audio track volume
0x00, 0x00, // reserved
0x00, 0x01, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x01, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x40, 0x00, 0x00, 0x00, // transformation: unity matrix
(track.width & 0xFF00) >> 8,
track.width & 0xFF,
0x00, 0x00, // width
(track.height & 0xFF00) >> 8,
track.height & 0xFF,
0x00, 0x00 // height
]);
return box(types.tkhd, result);
};
/**
* Generate a track fragment (traf) box. A traf box collects metadata
* about tracks in a movie fragment (moof) box.
*/
traf = function(track) {
var trackFragmentHeader, trackFragmentDecodeTime, trackFragmentRun,
sampleDependencyTable, dataOffset,
upperWordBaseMediaDecodeTime, lowerWordBaseMediaDecodeTime;
trackFragmentHeader = box(types.tfhd, new Uint8Array([
0x00, // version 0
0x00, 0x00, 0x3a, // flags
(track.id & 0xFF000000) >> 24,
(track.id & 0xFF0000) >> 16,
(track.id & 0xFF00) >> 8,
(track.id & 0xFF), // track_ID
0x00, 0x00, 0x00, 0x01, // sample_description_index
0x00, 0x00, 0x00, 0x00, // default_sample_duration
0x00, 0x00, 0x00, 0x00, // default_sample_size
0x00, 0x00, 0x00, 0x00 // default_sample_flags
]));
upperWordBaseMediaDecodeTime = Math.floor(track.baseMediaDecodeTime / (UINT32_MAX + 1));
lowerWordBaseMediaDecodeTime = Math.floor(track.baseMediaDecodeTime % (UINT32_MAX + 1));
trackFragmentDecodeTime = box(types.tfdt, new Uint8Array([
0x01, // version 1
0x00, 0x00, 0x00, // flags
// baseMediaDecodeTime
(upperWordBaseMediaDecodeTime >>> 24) & 0xFF,
(upperWordBaseMediaDecodeTime >>> 16) & 0xFF,
(upperWordBaseMediaDecodeTime >>> 8) & 0xFF,
upperWordBaseMediaDecodeTime & 0xFF,
(lowerWordBaseMediaDecodeTime >>> 24) & 0xFF,
(lowerWordBaseMediaDecodeTime >>> 16) & 0xFF,
(lowerWordBaseMediaDecodeTime >>> 8) & 0xFF,
lowerWordBaseMediaDecodeTime & 0xFF
]));
// the data offset specifies the number of bytes from the start of
// the containing moof to the first payload byte of the associated
// mdat
dataOffset = (32 + // tfhd
20 + // tfdt
8 + // traf header
16 + // mfhd
8 + // moof header
8); // mdat header
// audio tracks require less metadata
if (track.type === 'audio') {
trackFragmentRun = trun(track, dataOffset);
return box(types.traf,
trackFragmentHeader,
trackFragmentDecodeTime,
trackFragmentRun);
}
// video tracks should contain an independent and disposable samples
// box (sdtp)
// generate one and adjust offsets to match
sampleDependencyTable = sdtp(track);
trackFragmentRun = trun(track,
sampleDependencyTable.length + dataOffset);
return box(types.traf,
trackFragmentHeader,
trackFragmentDecodeTime,
trackFragmentRun,
sampleDependencyTable);
};
/**
* Generate a track box.
* @param track {object} a track definition
* @return {Uint8Array} the track box
*/
trak = function(track) {
track.duration = track.duration || 0xffffffff;
return box(types.trak,
tkhd(track),
mdia(track));
};
trex = function(track) {
var result = new Uint8Array([
0x00, // version 0
0x00, 0x00, 0x00, // flags
(track.id & 0xFF000000) >> 24,
(track.id & 0xFF0000) >> 16,
(track.id & 0xFF00) >> 8,
(track.id & 0xFF), // track_ID
0x00, 0x00, 0x00, 0x01, // default_sample_description_index
0x00, 0x00, 0x00, 0x00, // default_sample_duration
0x00, 0x00, 0x00, 0x00, // default_sample_size
0x00, 0x01, 0x00, 0x01 // default_sample_flags
]);
// the last two bytes of default_sample_flags is the sample
// degradation priority, a hint about the importance of this sample
// relative to others. Lower the degradation priority for all sample
// types other than video.
if (track.type !== 'video') {
result[result.length - 1] = 0x00;
}
return box(types.trex, result);
};
(function() {
var audioTrun, videoTrun, trunHeader;
// This method assumes all samples are uniform. That is, if a
// duration is present for the first sample, it will be present for
// all subsequent samples.
// see ISO/IEC 14496-12:2012, Section 8.8.8.1
trunHeader = function(samples, offset) {
var durationPresent = 0, sizePresent = 0,
flagsPresent = 0, compositionTimeOffset = 0;
// trun flag constants
if (samples.length) {
if (samples[0].duration !== undefined) {
durationPresent = 0x1;
}
if (samples[0].size !== undefined) {
sizePresent = 0x2;
}
if (samples[0].flags !== undefined) {
flagsPresent = 0x4;
}
if (samples[0].compositionTimeOffset !== undefined) {
compositionTimeOffset = 0x8;
}
}
return [
0x00, // version 0
0x00,
durationPresent | sizePresent | flagsPresent | compositionTimeOffset,
0x01, // flags
(samples.length & 0xFF000000) >>> 24,
(samples.length & 0xFF0000) >>> 16,
(samples.length & 0xFF00) >>> 8,
samples.length & 0xFF, // sample_count
(offset & 0xFF000000) >>> 24,
(offset & 0xFF0000) >>> 16,
(offset & 0xFF00) >>> 8,
offset & 0xFF // data_offset
];
};
videoTrun = function(track, offset) {
var bytes, samples, sample, i;
samples = track.samples || [];
offset += 8 + 12 + (16 * samples.length);
bytes = trunHeader(samples, offset);
for (i = 0; i < samples.length; i++) {
sample = samples[i];
bytes = bytes.concat([
(sample.duration & 0xFF000000) >>> 24,
(sample.duration & 0xFF0000) >>> 16,
(sample.duration & 0xFF00) >>> 8,
sample.duration & 0xFF, // sample_duration
(sample.size & 0xFF000000) >>> 24,
(sample.size & 0xFF0000) >>> 16,
(sample.size & 0xFF00) >>> 8,
sample.size & 0xFF, // sample_size
(sample.flags.isLeading << 2) | sample.flags.dependsOn,
(sample.flags.isDependedOn << 6) |
(sample.flags.hasRedundancy << 4) |
(sample.flags.paddingValue << 1) |
sample.flags.isNonSyncSample,
sample.flags.degradationPriority & 0xF0 << 8,
sample.flags.degradationPriority & 0x0F, // sample_flags
(sample.compositionTimeOffset & 0xFF000000) >>> 24,
(sample.compositionTimeOffset & 0xFF0000) >>> 16,
(sample.compositionTimeOffset & 0xFF00) >>> 8,
sample.compositionTimeOffset & 0xFF // sample_composition_time_offset
]);
}
return box(types.trun, new Uint8Array(bytes));
};
audioTrun = function(track, offset) {
var bytes, samples, sample, i;
samples = track.samples || [];
offset += 8 + 12 + (8 * samples.length);
bytes = trunHeader(samples, offset);
for (i = 0; i < samples.length; i++) {
sample = samples[i];
bytes = bytes.concat([
(sample.duration & 0xFF000000) >>> 24,
(sample.duration & 0xFF0000) >>> 16,
(sample.duration & 0xFF00) >>> 8,
sample.duration & 0xFF, // sample_duration
(sample.size & 0xFF000000) >>> 24,
(sample.size & 0xFF0000) >>> 16,
(sample.size & 0xFF00) >>> 8,
sample.size & 0xFF]); // sample_size
}
return box(types.trun, new Uint8Array(bytes));
};
trun = function(track, offset) {
if (track.type === 'audio') {
return audioTrun(track, offset);
}
return videoTrun(track, offset);
};
}());
module.exports = {
ftyp: ftyp,
mdat: mdat,
moof: moof,
moov: moov,
initSegment: function(tracks) {
var
fileType = ftyp(),
movie = moov(tracks),
result;
result = new Uint8Array(fileType.byteLength + movie.byteLength);
result.set(fileType);
result.set(movie, fileType.byteLength);
return result;
}
};
},{}],12:[function(require,module,exports){
/**
* mux.js
*
* Copyright (c) 2015 Brightcove
* All rights reserved.
*
* A stream-based mp2t to mp4 converter. This utility can be used to
* deliver mp4s to a SourceBuffer on platforms that support native
* Media Source Extensions.
*/
'use strict';
var Stream = require('../utils/stream.js');
var mp4 = require('./mp4-generator.js');
var m2ts = require('../m2ts/m2ts.js');
var AdtsStream = require('../codecs/adts.js');
var H264Stream = require('../codecs/h264').H264Stream;
var AacStream = require('../aac');
var coneOfSilence = require('../data/silence');
var clock = require('../utils/clock');
// constants
var AUDIO_PROPERTIES = [
'audioobjecttype',
'channelcount',
'samplerate',
'samplingfrequencyindex',
'samplesize'
];
var VIDEO_PROPERTIES = [
'width',
'height',
'profileIdc',
'levelIdc',
'profileCompatibility'
];
var ONE_SECOND_IN_TS = 90000; // 90kHz clock
// object types
var VideoSegmentStream, AudioSegmentStream, Transmuxer, CoalesceStream;
// Helper functions
var
createDefaultSample,
isLikelyAacData,
collectDtsInfo,
clearDtsInfo,
calculateTrackBaseMediaDecodeTime,
arrayEquals,
sumFrameByteLengths;
/**
* Default sample object
* see ISO/IEC 14496-12:2012, section 8.6.4.3
*/
createDefaultSample = function() {
return {
size: 0,
flags: {
isLeading: 0,
dependsOn: 1,
isDependedOn: 0,
hasRedundancy: 0,
degradationPriority: 0
}
};
};
isLikelyAacData = function(data) {
if ((data[0] === 'I'.charCodeAt(0)) &&
(data[1] === 'D'.charCodeAt(0)) &&
(data[2] === '3'.charCodeAt(0))) {
return true;
}
return false;
};
/**
* Compare two arrays (even typed) for same-ness
*/
arrayEquals = function(a, b) {
var
i;
if (a.length !== b.length) {
return false;
}
// compare the value of each element in the array
for (i = 0; i < a.length; i++) {
if (a[i] !== b[i]) {
return false;
}
}
return true;
};
/**
* Sum the `byteLength` properties of the data in each AAC frame
*/
sumFrameByteLengths = function(array) {
var
i,
currentObj,
sum = 0;
// sum the byteLength's all each nal unit in the frame
for (i = 0; i < array.length; i++) {
currentObj = array[i];
sum += currentObj.data.byteLength;
}
return sum;
};
/**
* Constructs a single-track, ISO BMFF media segment from AAC data
* events. The output of this stream can be fed to a SourceBuffer
* configured with a suitable initialization segment.
*/
AudioSegmentStream = function(track) {
var
adtsFrames = [],
sequenceNumber = 0,
earliestAllowedDts = 0,
audioAppendStartTs = 0,
videoBaseMediaDecodeTime = Infinity;
AudioSegmentStream.prototype.init.call(this);
this.push = function(data) {
collectDtsInfo(track, data);
if (track) {
AUDIO_PROPERTIES.forEach(function(prop) {
track[prop] = data[prop];
});
}
// buffer audio data until end() is called
adtsFrames.push(data);
};
this.setEarliestDts = function(earliestDts) {
earliestAllowedDts = earliestDts - track.timelineStartInfo.baseMediaDecodeTime;
};
this.setVideoBaseMediaDecodeTime = function(baseMediaDecodeTime) {
videoBaseMediaDecodeTime = baseMediaDecodeTime;
};
this.setAudioAppendStart = function(timestamp) {
audioAppendStartTs = timestamp;
};
this.flush = function() {
var
frames,
moof,
mdat,
boxes;
// return early if no audio data has been observed
if (adtsFrames.length === 0) {
this.trigger('done', 'AudioSegmentStream');
return;
}
frames = this.trimAdtsFramesByEarliestDts_(adtsFrames);
track.baseMediaDecodeTime = calculateTrackBaseMediaDecodeTime(track);
this.prefixWithSilence_(track, frames);
// we have to build the index from byte locations to
// samples (that is, adts frames) in the audio data
track.samples = this.generateSampleTable_(frames);
// concatenate the audio data to constuct the mdat
mdat = mp4.mdat(this.concatenateFrameData_(frames));
adtsFrames = [];
moof = mp4.moof(sequenceNumber, [track]);
boxes = new Uint8Array(moof.byteLength + mdat.byteLength);
// bump the sequence number for next time
sequenceNumber++;
boxes.set(moof);
boxes.set(mdat, moof.byteLength);
clearDtsInfo(track);
this.trigger('data', {track: track, boxes: boxes});
this.trigger('done', 'AudioSegmentStream');
};
// Possibly pad (prefix) the audio track with silence if appending this track
// would lead to the introduction of a gap in the audio buffer
this.prefixWithSilence_ = function(track, frames) {
var
baseMediaDecodeTimeTs,
frameDuration = 0,
audioGapDuration = 0,
audioFillFrameCount = 0,
audioFillDuration = 0,
silentFrame,
i;
if (!frames.length) {
return;
}
baseMediaDecodeTimeTs = clock.audioTsToVideoTs(track.baseMediaDecodeTime, track.samplerate);
// determine frame clock duration based on sample rate, round up to avoid overfills
frameDuration = Math.ceil(ONE_SECOND_IN_TS / (track.samplerate / 1024));
if (audioAppendStartTs && videoBaseMediaDecodeTime) {
// insert the shortest possible amount (audio gap or audio to video gap)
audioGapDuration =
baseMediaDecodeTimeTs - Math.max(audioAppendStartTs, videoBaseMediaDecodeTime);
// number of full frames in the audio gap
audioFillFrameCount = Math.floor(audioGapDuration / frameDuration);
audioFillDuration = audioFillFrameCount * frameDuration;
}
// don't attempt to fill gaps smaller than a single frame or larger
// than a half second
if (audioFillFrameCount < 1 || audioFillDuration > ONE_SECOND_IN_TS / 2) {
return;
}
silentFrame = coneOfSilence[track.samplerate];
if (!silentFrame) {
// we don't have a silent frame pregenerated for the sample rate, so use a frame
// from the content instead
silentFrame = frames[0].data;
}
for (i = 0; i < audioFillFrameCount; i++) {
frames.splice(i, 0, {
data: silentFrame
});
}
track.baseMediaDecodeTime -=
Math.floor(clock.videoTsToAudioTs(audioFillDuration, track.samplerate));
};
// If the audio segment extends before the earliest allowed dts
// value, remove AAC frames until starts at or after the earliest
// allowed DTS so that we don't end up with a negative baseMedia-
// DecodeTime for the audio track
this.trimAdtsFramesByEarliestDts_ = function(adtsFrames) {
if (track.minSegmentDts >= earliestAllowedDts) {
return adtsFrames;
}
// We will need to recalculate the earliest segment Dts
track.minSegmentDts = Infinity;
return adtsFrames.filter(function(currentFrame) {
// If this is an allowed frame, keep it and record it's Dts
if (currentFrame.dts >= earliestAllowedDts) {
track.minSegmentDts = Math.min(track.minSegmentDts, currentFrame.dts);
track.minSegmentPts = track.minSegmentDts;
return true;
}
// Otherwise, discard it
return false;
});
};
// generate the track's raw mdat data from an array of frames
this.generateSampleTable_ = function(frames) {
var
i,
currentFrame,
samples = [];
for (i = 0; i < frames.length; i++) {
currentFrame = frames[i];
samples.push({
size: currentFrame.data.byteLength,
duration: 1024 // For AAC audio, all samples contain 1024 samples
});
}
return samples;
};
// generate the track's sample table from an array of frames
this.concatenateFrameData_ = function(frames) {
var
i,
currentFrame,
dataOffset = 0,
data = new Uint8Array(sumFrameByteLengths(frames));
for (i = 0; i < frames.length; i++) {
currentFrame = frames[i];
data.set(currentFrame.data, dataOffset);
dataOffset += currentFrame.data.byteLength;
}
return data;
};
};
AudioSegmentStream.prototype = new Stream();
/**
* Constructs a single-track, ISO BMFF media segment from H264 data
* events. The output of this stream can be fed to a SourceBuffer
* configured with a suitable initialization segment.
* @param track {object} track metadata configuration
* @param options {object} transmuxer options object
* @param options.alignGopsAtEnd {boolean} If true, start from the end of the
* gopsToAlignWith list when attempting to align gop pts
*/
VideoSegmentStream = function(track, options) {
var
sequenceNumber = 0,
nalUnits = [],
gopsToAlignWith = [],
config,
pps;
options = options || {};
VideoSegmentStream.prototype.init.call(this);
delete track.minPTS;
this.gopCache_ = [];
this.push = function(nalUnit) {
collectDtsInfo(track, nalUnit);
// record the track config
if (nalUnit.nalUnitType === 'seq_parameter_set_rbsp' && !config) {
config = nalUnit.config;
track.sps = [nalUnit.data];
VIDEO_PROPERTIES.forEach(function(prop) {
track[prop] = config[prop];
}, this);
}
if (nalUnit.nalUnitType === 'pic_parameter_set_rbsp' &&
!pps) {
pps = nalUnit.data;
track.pps = [nalUnit.data];
}
// buffer video until flush() is called
nalUnits.push(nalUnit);
};
this.flush = function() {
var
frames,
gopForFusion,
gops,
moof,
mdat,
boxes;
// Throw away nalUnits at the start of the byte stream until
// we find the first AUD
while (nalUnits.length) {
if (nalUnits[0].nalUnitType === 'access_unit_delimiter_rbsp') {
break;
}
nalUnits.shift();
}
// Return early if no video data has been observed
if (nalUnits.length === 0) {
this.resetStream_();
this.trigger('done', 'VideoSegmentStream');
return;
}
// Organize the raw nal-units into arrays that represent
// higher-level constructs such as frames and gops
// (group-of-pictures)
frames = this.groupNalsIntoFrames_(nalUnits);
gops = this.groupFramesIntoGops_(frames);
// If the first frame of this fragment is not a keyframe we have
// a problem since MSE (on Chrome) requires a leading keyframe.
//
// We have two approaches to repairing this situation:
// 1) GOP-FUSION:
// This is where we keep track of the GOPS (group-of-pictures)
// from previous fragments and attempt to find one that we can
// prepend to the current fragment in order to create a valid
// fragment.
// 2) KEYFRAME-PULLING:
// Here we search for the first keyframe in the fragment and
// throw away all the frames between the start of the fragment
// and that keyframe. We then extend the duration and pull the
// PTS of the keyframe forward so that it covers the time range
// of the frames that were disposed of.
//
// #1 is far prefereable over #2 which can cause "stuttering" but
// requires more things to be just right.
if (!gops[0][0].keyFrame) {
// Search for a gop for fusion from our gopCache
gopForFusion = this.getGopForFusion_(nalUnits[0], track);
if (gopForFusion) {
gops.unshift(gopForFusion);
// Adjust Gops' metadata to account for the inclusion of the
// new gop at the beginning
gops.byteLength += gopForFusion.byteLength;
gops.nalCount += gopForFusion.nalCount;
gops.pts = gopForFusion.pts;
gops.dts = gopForFusion.dts;
gops.duration += gopForFusion.duration;
} else {
// If we didn't find a candidate gop fall back to keyrame-pulling
gops = this.extendFirstKeyFrame_(gops);
}
}
// Trim gops to align with gopsToAlignWith
if (gopsToAlignWith.length) {
var alignedGops;
if (options.alignGopsAtEnd) {
alignedGops = this.alignGopsAtEnd_(gops);
} else {
alignedGops = this.alignGopsAtStart_(gops);
}
if (!alignedGops) {
// save all the nals in the last GOP into the gop cache
this.gopCache_.unshift({
gop: gops.pop(),
pps: track.pps,
sps: track.sps
});
// Keep a maximum of 6 GOPs in the cache
this.gopCache_.length = Math.min(6, this.gopCache_.length);
// Clear nalUnits
nalUnits = [];
// return early no gops can be aligned with desired gopsToAlignWith
this.resetStream_();
this.trigger('done', 'VideoSegmentStream');
return;
}
// Some gops were trimmed. clear dts info so minSegmentDts and pts are correct
// when recalculated before sending off to CoalesceStream
clearDtsInfo(track);
gops = alignedGops;
}
collectDtsInfo(track, gops);
// First, we have to build the index from byte locations to
// samples (that is, frames) in the video data
track.samples = this.generateSampleTable_(gops);
// Concatenate the video data and construct the mdat
mdat = mp4.mdat(this.concatenateNalData_(gops));
track.baseMediaDecodeTime = calculateTrackBaseMediaDecodeTime(track);
this.trigger('processedGopsInfo', gops.map(function(gop) {
return {
pts: gop.pts,
dts: gop.dts,
byteLength: gop.byteLength
};
}));
// save all the nals in the last GOP into the gop cache
this.gopCache_.unshift({
gop: gops.pop(),
pps: track.pps,
sps: track.sps
});
// Keep a maximum of 6 GOPs in the cache
this.gopCache_.length = Math.min(6, this.gopCache_.length);
// Clear nalUnits
nalUnits = [];
this.trigger('baseMediaDecodeTime', track.baseMediaDecodeTime);
this.trigger('timelineStartInfo', track.timelineStartInfo);
moof = mp4.moof(sequenceNumber, [track]);
// it would be great to allocate this array up front instead of
// throwing away hundreds of media segment fragments
boxes = new Uint8Array(moof.byteLength + mdat.byteLength);
// Bump the sequence number for next time
sequenceNumber++;
boxes.set(moof);
boxes.set(mdat, moof.byteLength);
this.trigger('data', {track: track, boxes: boxes});
this.resetStream_();
// Continue with the flush process now
this.trigger('done', 'VideoSegmentStream');
};
this.resetStream_ = function() {
clearDtsInfo(track);
// reset config and pps because they may differ across segments
// for instance, when we are rendition switching
config = undefined;
pps = undefined;
};
// Search for a candidate Gop for gop-fusion from the gop cache and
// return it or return null if no good candidate was found
this.getGopForFusion_ = function(nalUnit) {
var
halfSecond = 45000, // Half-a-second in a 90khz clock
allowableOverlap = 10000, // About 3 frames @ 30fps
nearestDistance = Infinity,
dtsDistance,
nearestGopObj,
currentGop,
currentGopObj,
i;
// Search for the GOP nearest to the beginning of this nal unit
for (i = 0; i < this.gopCache_.length; i++) {
currentGopObj = this.gopCache_[i];
currentGop = currentGopObj.gop;
// Reject Gops with different SPS or PPS
if (!(track.pps && arrayEquals(track.pps[0], currentGopObj.pps[0])) ||
!(track.sps && arrayEquals(track.sps[0], currentGopObj.sps[0]))) {
continue;
}
// Reject Gops that would require a negative baseMediaDecodeTime
if (currentGop.dts < track.timelineStartInfo.dts) {
continue;
}
// The distance between the end of the gop and the start of the nalUnit
dtsDistance = (nalUnit.dts - currentGop.dts) - currentGop.duration;
// Only consider GOPS that start before the nal unit and end within
// a half-second of the nal unit
if (dtsDistance >= -allowableOverlap &&
dtsDistance <= halfSecond) {
// Always use the closest GOP we found if there is more than
// one candidate
if (!nearestGopObj ||
nearestDistance > dtsDistance) {
nearestGopObj = currentGopObj;
nearestDistance = dtsDistance;
}
}
}
if (nearestGopObj) {
return nearestGopObj.gop;
}
return null;
};
this.extendFirstKeyFrame_ = function(gops) {
var currentGop;
if (!gops[0][0].keyFrame && gops.length > 1) {
// Remove the first GOP
currentGop = gops.shift();
gops.byteLength -= currentGop.byteLength;
gops.nalCount -= currentGop.nalCount;
// Extend the first frame of what is now the
// first gop to cover the time period of the
// frames we just removed
gops[0][0].dts = currentGop.dts;
gops[0][0].pts = currentGop.pts;
gops[0][0].duration += currentGop.duration;
}
return gops;
};
// Convert an array of nal units into an array of frames with each frame being
// composed of the nal units that make up that frame
// Also keep track of cummulative data about the frame from the nal units such
// as the frame duration, starting pts, etc.
this.groupNalsIntoFrames_ = function(nalUnits) {
var
i,
currentNal,
currentFrame = [],
frames = [];
currentFrame.byteLength = 0;
for (i = 0; i < nalUnits.length; i++) {
currentNal = nalUnits[i];
// Split on 'aud'-type nal units
if (currentNal.nalUnitType === 'access_unit_delimiter_rbsp') {
// Since the very first nal unit is expected to be an AUD
// only push to the frames array when currentFrame is not empty
if (currentFrame.length) {
currentFrame.duration = currentNal.dts - currentFrame.dts;
frames.push(currentFrame);
}
currentFrame = [currentNal];
currentFrame.byteLength = currentNal.data.byteLength;
currentFrame.pts = currentNal.pts;
currentFrame.dts = currentNal.dts;
} else {
// Specifically flag key frames for ease of use later
if (currentNal.nalUnitType === 'slice_layer_without_partitioning_rbsp_idr') {
currentFrame.keyFrame = true;
}
currentFrame.duration = currentNal.dts - currentFrame.dts;
currentFrame.byteLength += currentNal.data.byteLength;
currentFrame.push(currentNal);
}
}
// For the last frame, use the duration of the previous frame if we
// have nothing better to go on
if (frames.length &&
(!currentFrame.duration ||
currentFrame.duration <= 0)) {
currentFrame.duration = frames[frames.length - 1].duration;
}
// Push the final frame
frames.push(currentFrame);
return frames;
};
// Convert an array of frames into an array of Gop with each Gop being composed
// of the frames that make up that Gop
// Also keep track of cummulative data about the Gop from the frames such as the
// Gop duration, starting pts, etc.
this.groupFramesIntoGops_ = function(frames) {
var
i,
currentFrame,
currentGop = [],
gops = [];
// We must pre-set some of the values on the Gop since we
// keep running totals of these values
currentGop.byteLength = 0;
currentGop.nalCount = 0;
currentGop.duration = 0;
currentGop.pts = frames[0].pts;
currentGop.dts = frames[0].dts;
// store some metadata about all the Gops
gops.byteLength = 0;
gops.nalCount = 0;
gops.duration = 0;
gops.pts = frames[0].pts;
gops.dts = frames[0].dts;
for (i = 0; i < frames.length; i++) {
currentFrame = frames[i];
if (currentFrame.keyFrame) {
// Since the very first frame is expected to be an keyframe
// only push to the gops array when currentGop is not empty
if (currentGop.length) {
gops.push(currentGop);
gops.byteLength += currentGop.byteLength;
gops.nalCount += currentGop.nalCount;
gops.duration += currentGop.duration;
}
currentGop = [currentFrame];
currentGop.nalCount = currentFrame.length;
currentGop.byteLength = currentFrame.byteLength;
currentGop.pts = currentFrame.pts;
currentGop.dts = currentFrame.dts;
currentGop.duration = currentFrame.duration;
} else {
currentGop.duration += currentFrame.duration;
currentGop.nalCount += currentFrame.length;
currentGop.byteLength += currentFrame.byteLength;
currentGop.push(currentFrame);
}
}
if (gops.length && currentGop.duration <= 0) {
currentGop.duration = gops[gops.length - 1].duration;
}
gops.byteLength += currentGop.byteLength;
gops.nalCount += currentGop.nalCount;
gops.duration += currentGop.duration;
// push the final Gop
gops.push(currentGop);
return gops;
};
// generate the track's sample table from an array of gops
this.generateSampleTable_ = function(gops, baseDataOffset) {
var
h, i,
sample,
currentGop,
currentFrame,
dataOffset = baseDataOffset || 0,
samples = [];
for (h = 0; h < gops.length; h++) {
currentGop = gops[h];
for (i = 0; i < currentGop.length; i++) {
currentFrame = currentGop[i];
sample = createDefaultSample();
sample.dataOffset = dataOffset;
sample.compositionTimeOffset = currentFrame.pts - currentFrame.dts;
sample.duration = currentFrame.duration;
sample.size = 4 * currentFrame.length; // Space for nal unit size
sample.size += currentFrame.byteLength;
if (currentFrame.keyFrame) {
sample.flags.dependsOn = 2;
}
dataOffset += sample.size;
samples.push(sample);
}
}
return samples;
};
// generate the track's raw mdat data from an array of gops
this.concatenateNalData_ = function(gops) {
var
h, i, j,
currentGop,
currentFrame,
currentNal,
dataOffset = 0,
nalsByteLength = gops.byteLength,
numberOfNals = gops.nalCount,
totalByteLength = nalsByteLength + 4 * numberOfNals,
data = new Uint8Array(totalByteLength),
view = new DataView(data.buffer);
// For each Gop..
for (h = 0; h < gops.length; h++) {
currentGop = gops[h];
// For each Frame..
for (i = 0; i < currentGop.length; i++) {
currentFrame = currentGop[i];
// For each NAL..
for (j = 0; j < currentFrame.length; j++) {
currentNal = currentFrame[j];
view.setUint32(dataOffset, currentNal.data.byteLength);
dataOffset += 4;
data.set(currentNal.data, dataOffset);
dataOffset += currentNal.data.byteLength;
}
}
}
return data;
};
// trim gop list to the first gop found that has a matching pts with a gop in the list
// of gopsToAlignWith starting from the START of the list
this.alignGopsAtStart_ = function(gops) {
var alignIndex, gopIndex, align, gop, byteLength, nalCount, duration, alignedGops;
byteLength = gops.byteLength;
nalCount = gops.nalCount;
duration = gops.duration;
alignIndex = gopIndex = 0;
while (alignIndex < gopsToAlignWith.length && gopIndex < gops.length) {
align = gopsToAlignWith[alignIndex];
gop = gops[gopIndex];
if (align.pts === gop.pts) {
break;
}
if (gop.pts > align.pts) {
// this current gop starts after the current gop we want to align on, so increment
// align index
alignIndex++;
continue;
}
// current gop starts before the current gop we want to align on. so increment gop
// index
gopIndex++;
byteLength -= gop.byteLength;
nalCount -= gop.nalCount;
duration -= gop.duration;
}
if (gopIndex === 0) {
// no gops to trim
return gops;
}
if (gopIndex === gops.length) {
// all gops trimmed, skip appending all gops
return null;
}
alignedGops = gops.slice(gopIndex);
alignedGops.byteLength = byteLength;
alignedGops.duration = duration;
alignedGops.nalCount = nalCount;
alignedGops.pts = alignedGops[0].pts;
alignedGops.dts = alignedGops[0].dts;
return alignedGops;
};
// trim gop list to the first gop found that has a matching pts with a gop in the list
// of gopsToAlignWith starting from the END of the list
this.alignGopsAtEnd_ = function(gops) {
var alignIndex, gopIndex, align, gop, alignEndIndex, matchFound;
alignIndex = gopsToAlignWith.length - 1;
gopIndex = gops.length - 1;
alignEndIndex = null;
matchFound = false;
while (alignIndex >= 0 && gopIndex >= 0) {
align = gopsToAlignWith[alignIndex];
gop = gops[gopIndex];
if (align.pts === gop.pts) {
matchFound = true;
break;
}
if (align.pts > gop.pts) {
alignIndex--;
continue;
}
if (alignIndex === gopsToAlignWith.length - 1) {
// gop.pts is greater than the last alignment candidate. If no match is found
// by the end of this loop, we still want to append gops that come after this
// point
alignEndIndex = gopIndex;
}
gopIndex--;
}
if (!matchFound && alignEndIndex === null) {
return null;
}
var trimIndex;
if (matchFound) {
trimIndex = gopIndex;
} else {
trimIndex = alignEndIndex;
}
if (trimIndex === 0) {
return gops;
}
var alignedGops = gops.slice(trimIndex);
var metadata = alignedGops.reduce(function(total, gop) {
total.byteLength += gop.byteLength;
total.duration += gop.duration;
total.nalCount += gop.nalCount;
return total;
}, { byteLength: 0, duration: 0, nalCount: 0 });
alignedGops.byteLength = metadata.byteLength;
alignedGops.duration = metadata.duration;
alignedGops.nalCount = metadata.nalCount;
alignedGops.pts = alignedGops[0].pts;
alignedGops.dts = alignedGops[0].dts;
return alignedGops;
};
this.alignGopsWith = function(newGopsToAlignWith) {
gopsToAlignWith = newGopsToAlignWith;
};
};
VideoSegmentStream.prototype = new Stream();
/**
* Store information about the start and end of the track and the
* duration for each frame/sample we process in order to calculate
* the baseMediaDecodeTime
*/
collectDtsInfo = function(track, data) {
if (typeof data.pts === 'number') {
if (track.timelineStartInfo.pts === undefined) {
track.timelineStartInfo.pts = data.pts;
}
if (track.minSegmentPts === undefined) {
track.minSegmentPts = data.pts;
} else {
track.minSegmentPts = Math.min(track.minSegmentPts, data.pts);
}
if (track.maxSegmentPts === undefined) {
track.maxSegmentPts = data.pts;
} else {
track.maxSegmentPts = Math.max(track.maxSegmentPts, data.pts);
}
}
if (typeof data.dts === 'number') {
if (track.timelineStartInfo.dts === undefined) {
track.timelineStartInfo.dts = data.dts;
}
if (track.minSegmentDts === undefined) {
track.minSegmentDts = data.dts;
} else {
track.minSegmentDts = Math.min(track.minSegmentDts, data.dts);
}
if (track.maxSegmentDts === undefined) {
track.maxSegmentDts = data.dts;
} else {
track.maxSegmentDts = Math.max(track.maxSegmentDts, data.dts);
}
}
};
/**
* Clear values used to calculate the baseMediaDecodeTime between
* tracks
*/
clearDtsInfo = function(track) {
delete track.minSegmentDts;
delete track.maxSegmentDts;
delete track.minSegmentPts;
delete track.maxSegmentPts;
};
/**
* Calculate the track's baseMediaDecodeTime based on the earliest
* DTS the transmuxer has ever seen and the minimum DTS for the
* current track
*/
calculateTrackBaseMediaDecodeTime = function(track) {
var
baseMediaDecodeTime,
scale,
// Calculate the distance, in time, that this segment starts from the start
// of the timeline (earliest time seen since the transmuxer initialized)
timeSinceStartOfTimeline = track.minSegmentDts - track.timelineStartInfo.dts;
// track.timelineStartInfo.baseMediaDecodeTime is the location, in time, where
// we want the start of the first segment to be placed
baseMediaDecodeTime = track.timelineStartInfo.baseMediaDecodeTime;
// Add to that the distance this segment is from the very first
baseMediaDecodeTime += timeSinceStartOfTimeline;
// baseMediaDecodeTime must not become negative
baseMediaDecodeTime = Math.max(0, baseMediaDecodeTime);
if (track.type === 'audio') {
// Audio has a different clock equal to the sampling_rate so we need to
// scale the PTS values into the clock rate of the track
scale = track.samplerate / ONE_SECOND_IN_TS;
baseMediaDecodeTime *= scale;
baseMediaDecodeTime = Math.floor(baseMediaDecodeTime);
}
return baseMediaDecodeTime;
};
/**
* A Stream that can combine multiple streams (ie. audio & video)
* into a single output segment for MSE. Also supports audio-only
* and video-only streams.
*/
CoalesceStream = function(options, metadataStream) {
// Number of Tracks per output segment
// If greater than 1, we combine multiple
// tracks into a single segment
this.numberOfTracks = 0;
this.metadataStream = metadataStream;
if (typeof options.remux !== 'undefined') {
this.remuxTracks = !!options.remux;
} else {
this.remuxTracks = true;
}
this.pendingTracks = [];
this.videoTrack = null;
this.pendingBoxes = [];
this.pendingCaptions = [];
this.pendingMetadata = [];
this.pendingBytes = 0;
this.emittedTracks = 0;
CoalesceStream.prototype.init.call(this);
// Take output from multiple
this.push = function(output) {
// buffer incoming captions until the associated video segment
// finishes
if (output.text) {
return this.pendingCaptions.push(output);
}
// buffer incoming id3 tags until the final flush
if (output.frames) {
return this.pendingMetadata.push(output);
}
// Add this track to the list of pending tracks and store
// important information required for the construction of
// the final segment
this.pendingTracks.push(output.track);
this.pendingBoxes.push(output.boxes);
this.pendingBytes += output.boxes.byteLength;
if (output.track.type === 'video') {
this.videoTrack = output.track;
}
if (output.track.type === 'audio') {
this.audioTrack = output.track;
}
};
};
CoalesceStream.prototype = new Stream();
CoalesceStream.prototype.flush = function(flushSource) {
var
offset = 0,
event = {
captions: [],
captionStreams: {},
metadata: [],
info: {}
},
caption,
id3,
initSegment,
timelineStartPts = 0,
i;
if (this.pendingTracks.length < this.numberOfTracks) {
if (flushSource !== 'VideoSegmentStream' &&
flushSource !== 'AudioSegmentStream') {
// Return because we haven't received a flush from a data-generating
// portion of the segment (meaning that we have only recieved meta-data
// or captions.)
return;
} else if (this.remuxTracks) {
// Return until we have enough tracks from the pipeline to remux (if we
// are remuxing audio and video into a single MP4)
return;
} else if (this.pendingTracks.length === 0) {
// In the case where we receive a flush without any data having been
// received we consider it an emitted track for the purposes of coalescing
// `done` events.
// We do this for the case where there is an audio and video track in the
// segment but no audio data. (seen in several playlists with alternate
// audio tracks and no audio present in the main TS segments.)
this.emittedTracks++;
if (this.emittedTracks >= this.numberOfTracks) {
this.trigger('done');
this.emittedTracks = 0;
}
return;
}
}
if (this.videoTrack) {
timelineStartPts = this.videoTrack.timelineStartInfo.pts;
VIDEO_PROPERTIES.forEach(function(prop) {
event.info[prop] = this.videoTrack[prop];
}, this);
} else if (this.audioTrack) {
timelineStartPts = this.audioTrack.timelineStartInfo.pts;
AUDIO_PROPERTIES.forEach(function(prop) {
event.info[prop] = this.audioTrack[prop];
}, this);
}
if (this.pendingTracks.length === 1) {
event.type = this.pendingTracks[0].type;
} else {
event.type = 'combined';
}
this.emittedTracks += this.pendingTracks.length;
initSegment = mp4.initSegment(this.pendingTracks);
// Create a new typed array to hold the init segment
event.initSegment = new Uint8Array(initSegment.byteLength);
// Create an init segment containing a moov
// and track definitions
event.initSegment.set(initSegment);
// Create a new typed array to hold the moof+mdats
event.data = new Uint8Array(this.pendingBytes);
// Append each moof+mdat (one per track) together
for (i = 0; i < this.pendingBoxes.length; i++) {
event.data.set(this.pendingBoxes[i], offset);
offset += this.pendingBoxes[i].byteLength;
}
// Translate caption PTS times into second offsets into the
// video timeline for the segment, and add track info
for (i = 0; i < this.pendingCaptions.length; i++) {
caption = this.pendingCaptions[i];
caption.startTime = (caption.startPts - timelineStartPts);
caption.startTime /= 90e3;
caption.endTime = (caption.endPts - timelineStartPts);
caption.endTime /= 90e3;
event.captionStreams[caption.stream] = true;
event.captions.push(caption);
}
// Translate ID3 frame PTS times into second offsets into the
// video timeline for the segment
for (i = 0; i < this.pendingMetadata.length; i++) {
id3 = this.pendingMetadata[i];
id3.cueTime = (id3.pts - timelineStartPts);
id3.cueTime /= 90e3;
event.metadata.push(id3);
}
// We add this to every single emitted segment even though we only need
// it for the first
event.metadata.dispatchType = this.metadataStream.dispatchType;
// Reset stream state
this.pendingTracks.length = 0;
this.videoTrack = null;
this.pendingBoxes.length = 0;
this.pendingCaptions.length = 0;
this.pendingBytes = 0;
this.pendingMetadata.length = 0;
// Emit the built segment
this.trigger('data', event);
// Only emit `done` if all tracks have been flushed and emitted
if (this.emittedTracks >= this.numberOfTracks) {
this.trigger('done');
this.emittedTracks = 0;
}
};
/**
* A Stream that expects MP2T binary data as input and produces
* corresponding media segments, suitable for use with Media Source
* Extension (MSE) implementations that support the ISO BMFF byte
* stream format, like Chrome.
*/
Transmuxer = function(options) {
var
self = this,
hasFlushed = true,
videoTrack,
audioTrack;
Transmuxer.prototype.init.call(this);
options = options || {};
this.baseMediaDecodeTime = options.baseMediaDecodeTime || 0;
this.transmuxPipeline_ = {};
this.setupAacPipeline = function() {
var pipeline = {};
this.transmuxPipeline_ = pipeline;
pipeline.type = 'aac';
pipeline.metadataStream = new m2ts.MetadataStream();
// set up the parsing pipeline
pipeline.aacStream = new AacStream();
pipeline.audioTimestampRolloverStream = new m2ts.TimestampRolloverStream('audio');
pipeline.timedMetadataTimestampRolloverStream = new m2ts.TimestampRolloverStream('timed-metadata');
pipeline.adtsStream = new AdtsStream();
pipeline.coalesceStream = new CoalesceStream(options, pipeline.metadataStream);
pipeline.headOfPipeline = pipeline.aacStream;
pipeline.aacStream
.pipe(pipeline.audioTimestampRolloverStream)
.pipe(pipeline.adtsStream);
pipeline.aacStream
.pipe(pipeline.timedMetadataTimestampRolloverStream)
.pipe(pipeline.metadataStream)
.pipe(pipeline.coalesceStream);
pipeline.metadataStream.on('timestamp', function(frame) {
pipeline.aacStream.setTimestamp(frame.timeStamp);
});
pipeline.aacStream.on('data', function(data) {
if (data.type === 'timed-metadata' && !pipeline.audioSegmentStream) {
audioTrack = audioTrack || {
timelineStartInfo: {
baseMediaDecodeTime: self.baseMediaDecodeTime
},
codec: 'adts',
type: 'audio'
};
// hook up the audio segment stream to the first track with aac data
pipeline.coalesceStream.numberOfTracks++;
pipeline.audioSegmentStream = new AudioSegmentStream(audioTrack);
// Set up the final part of the audio pipeline
pipeline.adtsStream
.pipe(pipeline.audioSegmentStream)
.pipe(pipeline.coalesceStream);
}
});
// Re-emit any data coming from the coalesce stream to the outside world
pipeline.coalesceStream.on('data', this.trigger.bind(this, 'data'));
// Let the consumer know we have finished flushing the entire pipeline
pipeline.coalesceStream.on('done', this.trigger.bind(this, 'done'));
};
this.setupTsPipeline = function() {
var pipeline = {};
this.transmuxPipeline_ = pipeline;
pipeline.type = 'ts';
pipeline.metadataStream = new m2ts.MetadataStream();
// set up the parsing pipeline
pipeline.packetStream = new m2ts.TransportPacketStream();
pipeline.parseStream = new m2ts.TransportParseStream();
pipeline.elementaryStream = new m2ts.ElementaryStream();
pipeline.videoTimestampRolloverStream = new m2ts.TimestampRolloverStream('video');
pipeline.audioTimestampRolloverStream = new m2ts.TimestampRolloverStream('audio');
pipeline.timedMetadataTimestampRolloverStream = new m2ts.TimestampRolloverStream('timed-metadata');
pipeline.adtsStream = new AdtsStream();
pipeline.h264Stream = new H264Stream();
pipeline.captionStream = new m2ts.CaptionStream();
pipeline.coalesceStream = new CoalesceStream(options, pipeline.metadataStream);
pipeline.headOfPipeline = pipeline.packetStream;
// disassemble MPEG2-TS packets into elementary streams
pipeline.packetStream
.pipe(pipeline.parseStream)
.pipe(pipeline.elementaryStream);
// !!THIS ORDER IS IMPORTANT!!
// demux the streams
pipeline.elementaryStream
.pipe(pipeline.videoTimestampRolloverStream)
.pipe(pipeline.h264Stream);
pipeline.elementaryStream
.pipe(pipeline.audioTimestampRolloverStream)
.pipe(pipeline.adtsStream);
pipeline.elementaryStream
.pipe(pipeline.timedMetadataTimestampRolloverStream)
.pipe(pipeline.metadataStream)
.pipe(pipeline.coalesceStream);
// Hook up CEA-608/708 caption stream
pipeline.h264Stream.pipe(pipeline.captionStream)
.pipe(pipeline.coalesceStream);
pipeline.elementaryStream.on('data', function(data) {
var i;
if (data.type === 'metadata') {
i = data.tracks.length;
// scan the tracks listed in the metadata
while (i--) {
if (!videoTrack && data.tracks[i].type === 'video') {
videoTrack = data.tracks[i];
videoTrack.timelineStartInfo.baseMediaDecodeTime = self.baseMediaDecodeTime;
} else if (!audioTrack && data.tracks[i].type === 'audio') {
audioTrack = data.tracks[i];
audioTrack.timelineStartInfo.baseMediaDecodeTime = self.baseMediaDecodeTime;
}
}
// hook up the video segment stream to the first track with h264 data
if (videoTrack && !pipeline.videoSegmentStream) {
pipeline.coalesceStream.numberOfTracks++;
pipeline.videoSegmentStream = new VideoSegmentStream(videoTrack, options);
pipeline.videoSegmentStream.on('timelineStartInfo', function(timelineStartInfo) {
// When video emits timelineStartInfo data after a flush, we forward that
// info to the AudioSegmentStream, if it exists, because video timeline
// data takes precedence.
if (audioTrack) {
audioTrack.timelineStartInfo = timelineStartInfo;
// On the first segment we trim AAC frames that exist before the
// very earliest DTS we have seen in video because Chrome will
// interpret any video track with a baseMediaDecodeTime that is
// non-zero as a gap.
pipeline.audioSegmentStream.setEarliestDts(timelineStartInfo.dts);
}
});
pipeline.videoSegmentStream.on('processedGopsInfo',
self.trigger.bind(self, 'gopInfo'));
pipeline.videoSegmentStream.on('baseMediaDecodeTime', function(baseMediaDecodeTime) {
if (audioTrack) {
pipeline.audioSegmentStream.setVideoBaseMediaDecodeTime(baseMediaDecodeTime);
}
});
// Set up the final part of the video pipeline
pipeline.h264Stream
.pipe(pipeline.videoSegmentStream)
.pipe(pipeline.coalesceStream);
}
if (audioTrack && !pipeline.audioSegmentStream) {
// hook up the audio segment stream to the first track with aac data
pipeline.coalesceStream.numberOfTracks++;
pipeline.audioSegmentStream = new AudioSegmentStream(audioTrack);
// Set up the final part of the audio pipeline
pipeline.adtsStream
.pipe(pipeline.audioSegmentStream)
.pipe(pipeline.coalesceStream);
}
}
});
// Re-emit any data coming from the coalesce stream to the outside world
pipeline.coalesceStream.on('data', this.trigger.bind(this, 'data'));
// Let the consumer know we have finished flushing the entire pipeline
pipeline.coalesceStream.on('done', this.trigger.bind(this, 'done'));
};
// hook up the segment streams once track metadata is delivered
this.setBaseMediaDecodeTime = function(baseMediaDecodeTime) {
var pipeline = this.transmuxPipeline_;
this.baseMediaDecodeTime = baseMediaDecodeTime;
if (audioTrack) {
audioTrack.timelineStartInfo.dts = undefined;
audioTrack.timelineStartInfo.pts = undefined;
clearDtsInfo(audioTrack);
audioTrack.timelineStartInfo.baseMediaDecodeTime = baseMediaDecodeTime;
if (pipeline.audioTimestampRolloverStream) {
pipeline.audioTimestampRolloverStream.discontinuity();
}
}
if (videoTrack) {
if (pipeline.videoSegmentStream) {
pipeline.videoSegmentStream.gopCache_ = [];
pipeline.videoTimestampRolloverStream.discontinuity();
}
videoTrack.timelineStartInfo.dts = undefined;
videoTrack.timelineStartInfo.pts = undefined;
clearDtsInfo(videoTrack);
pipeline.captionStream.reset();
videoTrack.timelineStartInfo.baseMediaDecodeTime = baseMediaDecodeTime;
}
if (pipeline.timedMetadataTimestampRolloverStream) {
pipeline.timedMetadataTimestampRolloverStream.discontinuity();
}
};
this.setAudioAppendStart = function(timestamp) {
if (audioTrack) {
this.transmuxPipeline_.audioSegmentStream.setAudioAppendStart(timestamp);
}
};
this.alignGopsWith = function(gopsToAlignWith) {
if (videoTrack && this.transmuxPipeline_.videoSegmentStream) {
this.transmuxPipeline_.videoSegmentStream.alignGopsWith(gopsToAlignWith);
}
};
// feed incoming data to the front of the parsing pipeline
this.push = function(data) {
if (hasFlushed) {
var isAac = isLikelyAacData(data);
if (isAac && this.transmuxPipeline_.type !== 'aac') {
this.setupAacPipeline();
} else if (!isAac && this.transmuxPipeline_.type !== 'ts') {
this.setupTsPipeline();
}
hasFlushed = false;
}
this.transmuxPipeline_.headOfPipeline.push(data);
};
// flush any buffered data
this.flush = function() {
hasFlushed = true;
// Start at the top of the pipeline and flush all pending work
this.transmuxPipeline_.headOfPipeline.flush();
};
// Caption data has to be reset when seeking outside buffered range
this.resetCaptions = function() {
if (this.transmuxPipeline_.captionStream) {
this.transmuxPipeline_.captionStream.reset();
}
};
};
Transmuxer.prototype = new Stream();
module.exports = {
Transmuxer: Transmuxer,
VideoSegmentStream: VideoSegmentStream,
AudioSegmentStream: AudioSegmentStream,
AUDIO_PROPERTIES: AUDIO_PROPERTIES,
VIDEO_PROPERTIES: VIDEO_PROPERTIES
};
},{"../aac":1,"../codecs/adts.js":2,"../codecs/h264":3,"../data/silence":4,"../m2ts/m2ts.js":6,"../utils/clock":13,"../utils/stream.js":15,"./mp4-generator.js":11}],13:[function(require,module,exports){
var
ONE_SECOND_IN_TS = 90000, // 90kHz clock
secondsToVideoTs,
secondsToAudioTs,
videoTsToSeconds,
audioTsToSeconds,
audioTsToVideoTs,
videoTsToAudioTs;
secondsToVideoTs = function(seconds) {
return seconds * ONE_SECOND_IN_TS;
};
secondsToAudioTs = function(seconds, sampleRate) {
return seconds * sampleRate;
};
videoTsToSeconds = function(timestamp) {
return timestamp / ONE_SECOND_IN_TS;
};
audioTsToSeconds = function(timestamp, sampleRate) {
return timestamp / sampleRate;
};
audioTsToVideoTs = function(timestamp, sampleRate) {
return secondsToVideoTs(audioTsToSeconds(timestamp, sampleRate));
};
videoTsToAudioTs = function(timestamp, sampleRate) {
return secondsToAudioTs(videoTsToSeconds(timestamp), sampleRate);
};
module.exports = {
secondsToVideoTs: secondsToVideoTs,
secondsToAudioTs: secondsToAudioTs,
videoTsToSeconds: videoTsToSeconds,
audioTsToSeconds: audioTsToSeconds,
audioTsToVideoTs: audioTsToVideoTs,
videoTsToAudioTs: videoTsToAudioTs
};
},{}],14:[function(require,module,exports){
'use strict';
var ExpGolomb;
/**
* Parser for exponential Golomb codes, a variable-bitwidth number encoding
* scheme used by h264.
*/
ExpGolomb = function(workingData) {
var
// the number of bytes left to examine in workingData
workingBytesAvailable = workingData.byteLength,
// the current word being examined
workingWord = 0, // :uint
// the number of bits left to examine in the current word
workingBitsAvailable = 0; // :uint;
// ():uint
this.length = function() {
return (8 * workingBytesAvailable);
};
// ():uint
this.bitsAvailable = function() {
return (8 * workingBytesAvailable) + workingBitsAvailable;
};
// ():void
this.loadWord = function() {
var
position = workingData.byteLength - workingBytesAvailable,
workingBytes = new Uint8Array(4),
availableBytes = Math.min(4, workingBytesAvailable);
if (availableBytes === 0) {
throw new Error('no bytes available');
}
workingBytes.set(workingData.subarray(position,
position + availableBytes));
workingWord = new DataView(workingBytes.buffer).getUint32(0);
// track the amount of workingData that has been processed
workingBitsAvailable = availableBytes * 8;
workingBytesAvailable -= availableBytes;
};
// (count:int):void
this.skipBits = function(count) {
var skipBytes; // :int
if (workingBitsAvailable > count) {
workingWord <<= count;
workingBitsAvailable -= count;
} else {
count -= workingBitsAvailable;
skipBytes = Math.floor(count / 8);
count -= (skipBytes * 8);
workingBytesAvailable -= skipBytes;
this.loadWord();
workingWord <<= count;
workingBitsAvailable -= count;
}
};
// (size:int):uint
this.readBits = function(size) {
var
bits = Math.min(workingBitsAvailable, size), // :uint
valu = workingWord >>> (32 - bits); // :uint
// if size > 31, handle error
workingBitsAvailable -= bits;
if (workingBitsAvailable > 0) {
workingWord <<= bits;
} else if (workingBytesAvailable > 0) {
this.loadWord();
}
bits = size - bits;
if (bits > 0) {
return valu << bits | this.readBits(bits);
}
return valu;
};
// ():uint
this.skipLeadingZeros = function() {
var leadingZeroCount; // :uint
for (leadingZeroCount = 0; leadingZeroCount < workingBitsAvailable; ++leadingZeroCount) {
if ((workingWord & (0x80000000 >>> leadingZeroCount)) !== 0) {
// the first bit of working word is 1
workingWord <<= leadingZeroCount;
workingBitsAvailable -= leadingZeroCount;
return leadingZeroCount;
}
}
// we exhausted workingWord and still have not found a 1
this.loadWord();
return leadingZeroCount + this.skipLeadingZeros();
};
// ():void
this.skipUnsignedExpGolomb = function() {
this.skipBits(1 + this.skipLeadingZeros());
};
// ():void
this.skipExpGolomb = function() {
this.skipBits(1 + this.skipLeadingZeros());
};
// ():uint
this.readUnsignedExpGolomb = function() {
var clz = this.skipLeadingZeros(); // :uint
return this.readBits(clz + 1) - 1;
};
// ():int
this.readExpGolomb = function() {
var valu = this.readUnsignedExpGolomb(); // :int
if (0x01 & valu) {
// the number is odd if the low order bit is set
return (1 + valu) >>> 1; // add 1 to make it even, and divide by 2
}
return -1 * (valu >>> 1); // divide by two then make it negative
};
// Some convenience functions
// :Boolean
this.readBoolean = function() {
return this.readBits(1) === 1;
};
// ():int
this.readUnsignedByte = function() {
return this.readBits(8);
};
this.loadWord();
};
module.exports = ExpGolomb;
},{}],15:[function(require,module,exports){
/**
* mux.js
*
* Copyright (c) 2014 Brightcove
* All rights reserved.
*
* A lightweight readable stream implemention that handles event dispatching.
* Objects that inherit from streams should call init in their constructors.
*/
'use strict';
var Stream = function() {
this.init = function() {
var listeners = {};
/**
* Add a listener for a specified event type.
* @param type {string} the event name
* @param listener {function} the callback to be invoked when an event of
* the specified type occurs
*/
this.on = function(type, listener) {
if (!listeners[type]) {
listeners[type] = [];
}
listeners[type] = listeners[type].concat(listener);
};
/**
* Remove a listener for a specified event type.
* @param type {string} the event name
* @param listener {function} a function previously registered for this
* type of event through `on`
*/
this.off = function(type, listener) {
var index;
if (!listeners[type]) {
return false;
}
index = listeners[type].indexOf(listener);
listeners[type] = listeners[type].slice();
listeners[type].splice(index, 1);
return index > -1;
};
/**
* Trigger an event of the specified type on this stream. Any additional
* arguments to this function are passed as parameters to event listeners.
* @param type {string} the event name
*/
this.trigger = function(type) {
var callbacks, i, length, args;
callbacks = listeners[type];
if (!callbacks) {
return;
}
// Slicing the arguments on every invocation of this method
// can add a significant amount of overhead. Avoid the
// intermediate object creation for the common case of a
// single callback argument
if (arguments.length === 2) {
length = callbacks.length;
for (i = 0; i < length; ++i) {
callbacks[i].call(this, arguments[1]);
}
} else {
args = [];
i = arguments.length;
for (i = 1; i < arguments.length; ++i) {
args.push(arguments[i]);
}
length = callbacks.length;
for (i = 0; i < length; ++i) {
callbacks[i].apply(this, args);
}
}
};
/**
* Destroys the stream and cleans up.
*/
this.dispose = function() {
listeners = {};
};
};
};
/**
* Forwards all `data` events on this stream to the destination stream. The
* destination stream should provide a method `push` to receive the data
* events as they arrive.
* @param destination {stream} the stream that will receive all `data` events
* @param autoFlush {boolean} if false, we will not call `flush` on the destination
* when the current stream emits a 'done' event
* @see http://nodejs.org/api/stream.html#stream_readable_pipe_destination_options
*/
Stream.prototype.pipe = function(destination) {
this.on('data', function(data) {
destination.push(data);
});
this.on('done', function(flushSource) {
destination.flush(flushSource);
});
return destination;
};
// Default stream functions that are expected to be overridden to perform
// actual work. These are provided by the prototype as a sort of no-op
// implementation so that we don't have to check for their existence in the
// `pipe` function above.
Stream.prototype.push = function(data) {
this.trigger('data', data);
};
Stream.prototype.flush = function(flushSource) {
this.trigger('done', flushSource);
};
module.exports = Stream;
},{}]},{},[10])(10)
});