/// <summary>
/// Reads the chunk describing the waveform format from the underlying stream.
/// </summary>
/// <returns>The waveform format.</returns>
private WaveformFormat ReadFormatChunk()
{
var chunkHeader = ReadChunkHeader(WaveformFileFormat.FormatChunkId);
if (chunkHeader.PayloadSize != WaveformFileFormat.FormatChunkPayloadSize)
{
throw new InvalidDataException("Unexpected format chunk size.");
}
var formatTag = _stream.ReadAsInt16();
if (formatTag != WaveformFileFormat.PcmFormatTag)
{
throw new InvalidDataException("Unsupported format.");
}
var channelsCount = _stream.ReadAsInt16();
var samplesPerSecond = _stream.ReadAsInt32();
var bytesPerSecond = _stream.ReadAsInt32();
var frameSize = _stream.ReadAsInt16();
var bitsPerSample = _stream.ReadAsInt16();
var sampleSize = WaveformFormat.GetSampleSize(bitsPerSample);
var expectedFrameSize = WaveformFormat.GetFrameSize(channelsCount, sampleSize);
var expectedBytesPerSecond = WaveformFormat.GetBytesPerSecond(frameSize, samplesPerSecond);
if (frameSize != expectedFrameSize ||
bytesPerSecond != expectedBytesPerSecond)
{
throw new InvalidDataException("Inconsistent sizes specified.");
}
return(new WaveformFormat(channelsCount, samplesPerSecond, bitsPerSample));
}