[NotNull] private static MemoryStream NormalizeAudioData(byte[] data)
{
#if NCRUNCH
return(new MemoryStream(data));
#endif
//Construct reader which can read the audio (whatever format it is in)
var reader = new StreamMediaFoundationReader(new MemoryStream(data));
var sampleProvider = reader.ToSampleProvider();
// find the max peak
float max = 0;
var buffer = new float[reader.WaveFormat.SampleRate];
int read;
do
{
read = sampleProvider.Read(buffer, 0, buffer.Length);
if (read > 0)
{
max = Math.Max(max, Enumerable.Range(0, read).Select(i => Math.Abs(buffer[i])).Max());
}
} while (read > 0);
if (Math.Abs(max) < float.Epsilon || max > 1.0f)
{
throw new InvalidOperationException("Audio normalization failed to find a reasonable peak volume");
}
//Write (as wav) with soft clipping and peak volume normalization
var output = new MemoryStream((int)(reader.Length * 4));
var input = new SoftClipSampleProvider(new VolumeSampleProvider(sampleProvider)
{
Volume = 1 / max - 0.05f
});
reader.Position = 0;
WaveFileWriter.WriteWavFileToStream(output, input.ToWaveProvider16());
return(output);
}
public MultichannelAudioPlayer([NotNull] IVoiceChannel voiceChannel, [NotNull] IEnumerable <IChannel> sources)
{
_voiceChannel = voiceChannel;
_threadEvent = new AutoResetEvent(true);
_thread = Task.Run(ThreadEntry);
//Sample provider which mixes together several sample providers
_mixerInput = new MixingSampleProvider(MixingFormat)
{
ReadFully = true
};
//Soft clip using opus
var clipper = new SoftClipSampleProvider(_mixerInput.ToMono());
//resample mix format to output format
_mixerOutput = new WdlResamplingSampleProvider(clipper, OutputFormat.SampleRate).ToStereo().ToWaveProvider16();
//Add all initial channels to the mixer
foreach (var source in sources)
{
Add(source);
}
}
