142 lines
3.9 KiB
C#
142 lines
3.9 KiB
C#
/* Copyright (c) 2019-present Evereal. All rights reserved. */
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using System;
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using System.IO;
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using System.Text;
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using UnityEngine;
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namespace Evereal.VideoCapture
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{
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public static class WavEncoder
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{
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private const uint HeaderSize = 44;
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private const float RescaleFactor = 32767; //to convert float to Int16
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public static void Save(string filepath, AudioClip clip, bool trim = false)
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{
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using (var fileStream = new FileStream(filepath, FileMode.Create))
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using (var writer = new BinaryWriter(fileStream))
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{
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uint length;
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var wav = GetWav(clip, out length, trim);
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writer.Write(wav, 0, (int)length);
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}
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}
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public static byte[] GetWav(AudioClip clip, out uint length, bool trim = false)
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{
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uint samples;
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var data = ConvertAndWrite(clip, out length, out samples, trim);
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WriteHeader(data, clip, length, samples);
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return data;
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}
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private static byte[] ConvertAndWrite(AudioClip clip, out uint length, out uint samplesAfterTrimming, bool trim)
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{
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var samples = new float[clip.samples * clip.channels];
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clip.GetData(samples, 0);
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var sampleCount = samples.Length;
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var start = 0;
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var end = sampleCount - 1;
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if (trim)
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{
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for (var i = 0; i < sampleCount; i++)
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{
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if ((short)(samples[i] * RescaleFactor) == 0)
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continue;
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start = i;
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break;
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}
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for (var i = sampleCount - 1; i >= 0; i--)
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{
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if ((short)(samples[i] * RescaleFactor) == 0)
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continue;
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end = i;
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break;
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}
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}
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var buffer = new byte[(sampleCount * 2) + HeaderSize];
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var p = HeaderSize;
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for (var i = start; i <= end; i++)
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{
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var value = (short)(samples[i] * RescaleFactor);
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buffer[p++] = (byte)(value >> 0);
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buffer[p++] = (byte)(value >> 8);
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}
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length = p;
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samplesAfterTrimming = (uint)(end - start + 1);
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return buffer;
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}
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private static void AddDataToBuffer(byte[] buffer, ref uint offset, byte[] addBytes)
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{
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foreach (var b in addBytes)
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{
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buffer[offset++] = b;
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}
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}
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private static void WriteHeader(byte[] stream, AudioClip clip, uint length, uint samples)
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{
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var hz = (uint)clip.frequency;
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var channels = (ushort)clip.channels;
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var offset = 0u;
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var riff = Encoding.UTF8.GetBytes("RIFF");
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AddDataToBuffer(stream, ref offset, riff);
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var chunkSize = BitConverter.GetBytes(length - 8);
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AddDataToBuffer(stream, ref offset, chunkSize);
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var wave = Encoding.UTF8.GetBytes("WAVE");
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AddDataToBuffer(stream, ref offset, wave);
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var fmt = Encoding.UTF8.GetBytes("fmt ");
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AddDataToBuffer(stream, ref offset, fmt);
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var subChunk1 = BitConverter.GetBytes(16u);
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AddDataToBuffer(stream, ref offset, subChunk1);
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//const ushort two = 2;
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const ushort one = 1;
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var audioFormat = BitConverter.GetBytes(one);
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AddDataToBuffer(stream, ref offset, audioFormat);
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var numChannels = BitConverter.GetBytes(channels);
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AddDataToBuffer(stream, ref offset, numChannels);
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var sampleRate = BitConverter.GetBytes(hz);
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AddDataToBuffer(stream, ref offset, sampleRate);
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var byteRate = BitConverter.GetBytes(hz * channels * 2); // sampleRate * bytesPerSample*number of channels, here 44100*2*2
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AddDataToBuffer(stream, ref offset, byteRate);
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var blockAlign = (ushort)(channels * 2);
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AddDataToBuffer(stream, ref offset, BitConverter.GetBytes(blockAlign));
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ushort bps = 16;
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var bitsPerSample = BitConverter.GetBytes(bps);
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AddDataToBuffer(stream, ref offset, bitsPerSample);
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var dataString = Encoding.UTF8.GetBytes("data");
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AddDataToBuffer(stream, ref offset, dataString);
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var subChunk2 = BitConverter.GetBytes(samples * 2);
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AddDataToBuffer(stream, ref offset, subChunk2);
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}
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}
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} |