public void Initialize(Stream stream)
{
_audioInfo = new WaveAudioInfoDecoder().ReadAudioInfo(stream);
_reader = new RiffReader(stream);
_bitsPerSample = _audioInfo.BitsPerSample;
_bytesPerSample = (int)Math.Ceiling(_audioInfo.BitsPerSample / 8.0);
_framesRemaining = _audioInfo.FrameCount;
_reader.Initialize();
_reader.SeekToChunk("data");
}
public AudioInfo ReadAudioInfo(Stream stream)
{
using (var reader = new RiffReader(stream))
{
try
{
reader.Initialize();
if (stream.Length != reader.RiffChunkSize + 8)
{
throw new AudioInvalidException("Stream is unexpectedly truncated.");
}
reader.BaseStream.Position = 8;
if (!reader.ReadFourCc().Equals("WAVE", StringComparison.Ordinal))
{
throw new AudioInvalidException("Not a Wave stream.");
}
var fmtChunkSize = reader.SeekToChunk("fmt ");
if (fmtChunkSize == 0)
{
throw new AudioInvalidException("Missing 'fmt' chunk.");
}
var isExtensible = false;
switch (reader.ReadUInt16())
{
// WAVE_FORMAT_PCM
case 1:
break;
// WAVE_FORMAT_EXTENSIBLE
case 0xFFFE:
isExtensible = true;
break;
default:
throw new AudioUnsupportedException("Only PCM wave streams are supported.");
}
var channels = reader.ReadUInt16();
var sampleRate = reader.ReadUInt32();
// Ignore nAvgBytesPerSec
stream.Seek(4, SeekOrigin.Current);
var blockAlign = reader.ReadUInt16();
// Use wValidBitsPerSample if this is WAVE_FORMAT_EXTENSIBLE
if (isExtensible)
{
stream.Seek(4, SeekOrigin.Current);
}
return(AudioInfo.CreateForLossless(
"LPCM",
channels,
reader.ReadUInt16(),
(int)sampleRate,
reader.SeekToChunk("data") / blockAlign));
}
catch (EndOfStreamException e)
{
// The end of the stream was unexpectedly reached
throw new AudioInvalidException(e.Message);
}
}
}
