/// <summary>
/// Converts a RIFF WAVE bitstream with header to raw samples.
/// </summary>
public RIFFWaveDecoder(BinaryReader reader)
{
// RIFF header
if (reader.ReadInt32() != RIFFWave.syncWord1)
{
throw new SyncException();
}
stream = reader.BaseStream;
stream.Position += 4; // File length
// Format header
if (reader.ReadInt64() != RIFFWave.syncWord2)
{
throw new SyncException();
}
stream.Position += 4; // Format header length
short sampleFormat = reader.ReadInt16(); // 1 = int, 3 = float, -2 = WAVE EX
channelCount = reader.ReadInt16();
sampleRate = reader.ReadInt32();
stream.Position += 4; // Bytes/sec
stream.Position += 2; // Block size in bytes
short bitDepth = reader.ReadInt16();
if (sampleFormat == -2)
{
// Extension size (22) - 2 bytes, valid bits per sample - 2 bytes, channel mask - 4 bytes
stream.Position += 8;
sampleFormat = reader.ReadInt16();
stream.Position += 15; // Skip the rest of the sub format GUID
}
if (sampleFormat == 1)
{
Bits = bitDepth switch {
8 => BitDepth.Int8,
16 => BitDepth.Int16,
24 => BitDepth.Int24,
_ => throw new IOException($"Unsupported bit depth for signed little endian integer: {bitDepth}.")
};
}
else if (sampleFormat == 3 && bitDepth == 32)
{
Bits = BitDepth.Float32;
}
else
{
throw new IOException($"Unsupported bit depth ({bitDepth}) for sample format {sampleFormat}.");
}
// Data header
int header = 0;
do
{
header = (header << 8) | reader.ReadByte();
}while (header != RIFFWave.syncWord3BE && stream.Position < stream.Length);
length = reader.ReadUInt32() * 8L / (long)Bits / ChannelCount;
dataStart = stream.Position;
this.reader = BlockBuffer <byte> .Create(reader, FormatConsts.blockSize);
}
