/// <summary>
/// Initializes a new instance of the AudioFormatHandler class.
/// </summary>
/// <param name="audioFormat">Audio format</param>
public AudioFormatHandler(AudioFormat audioFormat)
{
InputAudioFormat = audioFormat;
_defaultAudioFormat = new AudioFormat(AudioEncoding.Pcm, 1, 16000, 16, new AudioContainer(AudioContainerType.Wav));
}
private AudioFormat ParseContainerHeader(byte[] header)
{
AudioFormat parsedFormat = null;
using (Stream stream = new MemoryStream(header))
using (BinaryReader reader = new BinaryReader(stream))
{
if (InputAudioFormat.Container.ContainerType.Equals(AudioContainerType.Wav))
{
string label = GetChunkLabel(reader, stream, 0);
if (string.CompareOrdinal(label, "RIFF") != 0)
{
throw new InvalidDataException("Unable to find RIFF signature in header");
}
label = GetChunkLabel(reader, stream, 8);
if (string.CompareOrdinal(label, "WAVE") != 0)
{
throw new InvalidDataException("Unable to find WAVE signature in header");
}
bool isParsed = false;
while (!isParsed)
{
// Safe to cast to int because the header size can't be > 5k
label = GetChunkLabel(reader, stream, (int)stream.Position);
int chunkSize = reader.ReadInt32();
switch (label)
{
case "fmt ":
long currentStreamPosition = stream.Position;
AudioEncoding encoding = AudioEncoding.None;
if (reader.ReadInt16() == 1)
{
encoding = AudioEncoding.Pcm;
}
int channelsNumber = reader.ReadInt16();
int sampleRate = reader.ReadInt32();
// Skipping the unneeded format specs
stream.Position += 6;
int bitsPerSample = reader.ReadInt16();
parsedFormat = new AudioFormat(encoding, channelsNumber, sampleRate, bitsPerSample, new AudioContainer(AudioContainerType.Wav));
stream.Position = currentStreamPosition + chunkSize;
break;
case "data":
isParsed = true;
_parsingResult.DataChunckStart = (int)stream.Position;
if (parsedFormat == null)
{
throw new InvalidDataException("Unable to find the fmt chunk in header");
}
break;
default:
stream.Position += chunkSize;
break;
}
}
}
else
{
throw new InvalidDataException($"Unsupported container format: {InputAudioFormat.Container.ContainerType.ToString()}");
}
}
return(parsedFormat);
}
private int CalculateBytesPerSecond(AudioFormat format)
{
var count = (format.BitsPerSample * format.SampleRate * format.ChannelsNumber) / 8;
return(count);
}
