public void Decode(Stream input, Stream output, bool resample)
{
int resampleRate = 44100;
using OggReader reader = new OggReader(input);
using BinaryWriter writer = new BinaryWriter(output, System.Text.Encoding.ASCII, true);
using var decoder = OpusDecoder.Create(48000, reader.Channels);
LibResampler resampler = null;
if (resample)
{
resampler = new LibResampler(48000, resampleRate, reader.Channels);
}
bool isFirst = true;
long headerPosition = output.Position;
output.Position += 44;
Span <float> inputBuffer = default;
while (!reader.IsStreamFinished)
{
var frame = reader.ReadPacket();
if (isFirst)
{
inputBuffer = new float[decoder.GetSamples(frame.Span) * decoder.OutputChannels];
}
decoder.DecodeFloat(frame.Span, inputBuffer, out int dataLength);
var outputSamples = inputBuffer.Slice(0, dataLength);
if (isFirst)
{
//remove preskip
outputSamples = outputSamples.Slice(reader.Preskip);
isFirst = false;
}
Span <float> outputSpan = outputSamples;
if (resample)
{
float[] resampledSamples = new float[resampler.ResampleUpperBound(outputSamples.Length)];
resampler.Resample(outputSamples, resampledSamples, reader.IsStreamFinished, out int outputLength);
outputSpan = resampledSamples.AsSpan(0, outputLength);
}
foreach (float sample in outputSpan)
{
writer.Write(WaveWriter.ConvertSample(sample));
}
}
long endPosition = output.Position;
output.Position = headerPosition;
WaveWriter.WriteWAVHeader(output, reader.Channels, (int)(endPosition - headerPosition), resample ? resampleRate : 48000, 16);
output.Position = endPosition;
}
public void Encode(Stream input, Stream output)
{
using var bufferedWaveInput = new BufferedStream(input);
using var wav = new WaveReader(bufferedWaveInput);
byte channels = (byte)wav.Channels;
int resampleRate = wav.SampleRate < 24000 ? 24000 : 48000;
using var opus = External.Opus.OpusEncoder.Create(resampleRate, channels, channels > 1 ? Application.Audio : Application.Voip);
using var wrapper = new OggWrapper(output, channels, (ushort)opus.LookaheadSamples, true);
using var resampler = new LibResampler(wav.SampleRate, resampleRate, channels);
opus.Bitrate = channels > 1 ? Core.Settings.OpusMusicBitrate : Core.Settings.OpusVoiceBitrate;
int rawSampleCount = (int)Math.Round(resampleRate * Core.Settings.OpusFrameSize);
int samplesPerFrame = rawSampleCount * channels;
using var tempFloatBuffer = MemoryPool <float> .Shared.Rent(8192);
Span <float> tempFloatBufferSpan = tempFloatBuffer.Memory.Span;
using var tempByteBuffer = MemoryPool <byte> .Shared.Rent(8192);
Span <byte> tempByteBufferSpan = tempByteBuffer.Memory.Span;
int outputSamplesUpperBound = resampler.ResampleUpperBound(samplesPerFrame);
using var outputSampleBuffer = MemoryPool <float> .Shared.Rent(outputSamplesUpperBound * 10);
Span <float> outputSampleSpan = outputSampleBuffer.Memory.Span.Slice(0, outputSamplesUpperBound * 10);
int outputSpanStackPointer = 0;
bool AppendToOutputSpan(Span <float> inputSampleSpan, Span <float> outputSampleSpan)
{
int result = wav.Read(inputSampleSpan);
bool lastBuffer = false;
if (result < inputSampleSpan.Length)
{
lastBuffer = true;
int newSize = result - (result % channels);
inputSampleSpan = inputSampleSpan.Slice(0, newSize);
}
resampler.Resample(inputSampleSpan, outputSampleSpan.Slice(outputSpanStackPointer), lastBuffer, out var outputLength);
outputSpanStackPointer += outputLength;
return(!lastBuffer);
}
void MoveOutputToEncoded(bool lastFrame, Span <float> outputSampleSpan, Span <byte> encodedSampleSpan)
{
if (lastFrame)
{
outputSampleSpan.Slice(outputSpanStackPointer, samplesPerFrame - outputSpanStackPointer).Clear();
// TODO: Tweak the frame size for end frames to minimize silent time
}
opus.Encode(outputSampleSpan.Slice(0, samplesPerFrame), encodedSampleSpan, rawSampleCount, out int outlen);
wrapper.WritePacket(tempByteBuffer.Memory.Slice(0, outlen),
rawSampleCount,
lastFrame);
if (!lastFrame)
{
outputSampleSpan.Slice(samplesPerFrame, outputSpanStackPointer - samplesPerFrame).CopyTo(outputSampleSpan);
outputSpanStackPointer -= samplesPerFrame;
}
}
while (true)
{
bool lastFrame = false;
while (outputSpanStackPointer < samplesPerFrame && !lastFrame)
{
lastFrame = !AppendToOutputSpan(tempFloatBufferSpan, outputSampleSpan);
}
while (outputSpanStackPointer >= samplesPerFrame)
{
MoveOutputToEncoded(false, outputSampleSpan, tempByteBufferSpan);
}
if (lastFrame)
{
MoveOutputToEncoded(true, outputSampleSpan, tempByteBufferSpan);
break;
}
}
}
