public IChunk ReadNextChunk()
{
if (BR.BaseStream.Position + 4 >= BR.BaseStream.Length)
{
BR.BaseStream.Position += 4;
return null;
}
string chkid = (System.Text.UTF8Encoding.UTF8.GetString(BR.ReadBytes(4), 0, 4)).ToLower();
switch (chkid)
{
case "riff":
MasterChunk mc = new MasterChunk();
mc.chkID = new char[] { 'R', 'I', 'F', 'F' };
mc.chksize = BitConverter.ToInt32(BR.ReadBytes(4), 0);
mc.WAVEID = BR.ReadChars(4);
return mc;
case "fact":
FactChunk fc = new FactChunk();
fc.chkID = new char[] { 'f', 'a', 'c', 't' };
fc.chksize = BitConverter.ToInt32(BR.ReadBytes(4), 0);
fc.dwSampleLength = BitConverter.ToInt32(BR.ReadBytes(4), 0);
return fc;
case "data":
DataChunk dc = new DataChunk();
dc.chkID = new char[] { 'd', 'a', 't', 'a' };
dc.chksize = BitConverter.ToInt32(BR.ReadBytes(4), 0);
if (dc.chksize % 2 == 0)
dc.pad = 0;
else
dc.pad = 1;
dc.sampled_data = BR.ReadBytes(dc.chksize);
return dc;
case "fmt ":
FormatChunk fc2 = new FormatChunk();
fc2.chkID = new char[] { 'f', 'm', 't', ' ' };
fc2.chksize = BitConverter.ToInt32(BR.ReadBytes(4), 0);
fc2.wFormatTag = BitConverter.ToInt16(BR.ReadBytes(2), 0);
fc2.nChannels = BitConverter.ToInt16(BR.ReadBytes(2), 0);
fc2.nSamplesPerSec = BitConverter.ToInt32(BR.ReadBytes(4), 0);
fc2.nAvgBytesPerSec = BitConverter.ToInt32(BR.ReadBytes(4), 0);
fc2.nBlockAlign = BitConverter.ToInt16(BR.ReadBytes(2), 0);
fc2.wBitsPerSample = BitConverter.ToInt16(BR.ReadBytes(2), 0);
if (fc2.wFormatTag != (short)WaveHelper.Format_Code.WAVE_FORMAT_PCM)
{
fc2.cbSize = BitConverter.ToInt16(BR.ReadBytes(2), 0);
}
if ((int)fc2.wFormatTag == (int)WaveHelper.Format_Code.WAVE_FORMAT_EXTENSIBLE)
{
fc2.wValidBitsPerSample = BitConverter.ToInt16(BR.ReadBytes(2), 0);
fc2.dwChannelMask = BitConverter.ToInt32(BR.ReadBytes(4), 0);
fc2.SubFormat = BR.ReadChars(16);
}
return fc2;
default:
break;
}
return null;
}
public static void ChangeBitsPerSample(FormatChunk fmtchk, DataChunk datachk, int bitsPerSample)
{
if (fmtchk.wBitsPerSample == bitsPerSample)
return;
float[,] samples = GetSampleData(fmtchk, datachk);
datachk.sampled_data = GetRawData(samples, bitsPerSample);
datachk.chksize = datachk.sampled_data.Length;
fmtchk.wBitsPerSample = (short)bitsPerSample;
fmtchk.nBlockAlign = (short)(fmtchk.nChannels * (bitsPerSample / 8));
fmtchk.nAvgBytesPerSec = fmtchk.nBlockAlign * fmtchk.nSamplesPerSec;
}
public static float[,] GetSampleData(FormatChunk fmtchk, DataChunk datachk)
{
int bytesPerSample = fmtchk.wBitsPerSample / 8;
int channels = fmtchk.nChannels;
int samplePerChannel = (datachk.sampled_data.Length / bytesPerSample) / channels;
float[,] samples = new float[channels, samplePerChannel];
for (int x = 0; x < samplePerChannel; x++)
{
for (int i = 0; i < channels; i++)
{
switch (bytesPerSample)
{
case 1:
samples[i, x] = (datachk.sampled_data[(x * channels) + i] - 128) / 128.0f;
break;
case 2:
samples[i, x] = BitConverter.ToInt16(datachk.sampled_data,(x * 2 * channels) + (i * 2)) / (float)Int16.MaxValue;
break;
case 3:
samples[i, x] = ToInt24(datachk.sampled_data, (x * 3 * channels) + (i * 3)) / (float)8388607;
break;
case 4:
samples[i, x] = BitConverter.ToInt32(datachk.sampled_data, (x * 4 * channels) + (i * 4)) / (float)Int32.MaxValue;
break;
}
}
}
return samples;
}
