unsafe void decode_subframes(BitReader bitreader, FlacFrame frame)
{
fixed(int *r = residualBuffer, s = samplesBuffer)
for (int ch = 0; ch < PCM.ChannelCount; ch++)
{
// subframe header
uint t1 = bitreader.readbit(); // ?????? == 0
if (t1 != 0)
{
throw new Exception("unsupported subframe coding (ch == " + ch.ToString() + ")");
}
int type_code = (int)bitreader.readbits(6);
frame.subframes[ch].wbits = (int)bitreader.readbit();
if (frame.subframes[ch].wbits != 0)
{
frame.subframes[ch].wbits += (int)bitreader.read_unary();
}
frame.subframes[ch].obits = PCM.BitsPerSample - frame.subframes[ch].wbits;
switch (frame.ch_mode)
{
case ChannelMode.MidSide: frame.subframes[ch].obits += ch; break;
case ChannelMode.LeftSide: frame.subframes[ch].obits += ch; break;
case ChannelMode.RightSide: frame.subframes[ch].obits += 1 - ch; break;
}
frame.subframes[ch].best.type = (SubframeType)type_code;
frame.subframes[ch].best.order = 0;
if ((type_code & (uint)SubframeType.LPC) != 0)
{
frame.subframes[ch].best.order = (type_code - (int)SubframeType.LPC) + 1;
frame.subframes[ch].best.type = SubframeType.LPC;
}
else if ((type_code & (uint)SubframeType.Fixed) != 0)
{
frame.subframes[ch].best.order = (type_code - (int)SubframeType.Fixed);
frame.subframes[ch].best.type = SubframeType.Fixed;
}
frame.subframes[ch].best.residual = r + ch * Flake.MAX_BLOCKSIZE;
frame.subframes[ch].samples = s + ch * Flake.MAX_BLOCKSIZE;
// subframe
switch (frame.subframes[ch].best.type)
{
case SubframeType.Constant:
decode_subframe_constant(bitreader, frame, ch);
break;
case SubframeType.Verbatim:
decode_subframe_verbatim(bitreader, frame, ch);
break;
case SubframeType.Fixed:
decode_subframe_fixed(bitreader, frame, ch);
break;
case SubframeType.LPC:
decode_subframe_lpc(bitreader, frame, ch);
break;
default:
throw new Exception("invalid subframe type");
}
}
}
