int DecodeFrameImpl(IMpegFrame frame, Array dest, int destOffset)
{
Decoder.LayerDecoderBase curDecoder = null;
switch (frame.Layer)
{
case MpegLayer.LayerI:
if (_layerIDecoder == null)
{
_layerIDecoder = new Decoder.LayerIDecoder();
}
curDecoder = _layerIDecoder;
break;
case MpegLayer.LayerII:
if (_layerIIDecoder == null)
{
_layerIIDecoder = new Decoder.LayerIIDecoder();
}
curDecoder = _layerIIDecoder;
break;
case MpegLayer.LayerIII:
if (_layerIIIDecoder == null)
{
_layerIIIDecoder = new Decoder.LayerIIIDecoder();
}
curDecoder = _layerIIIDecoder;
break;
}
if (curDecoder != null)
{
curDecoder.SetEQ(_eqFactors);
curDecoder.StereoMode = StereoMode;
var cnt = curDecoder.DecodeFrame(frame, _ch0, _ch1);
if (frame.ChannelMode == MpegChannelMode.Mono)
{
Buffer.BlockCopy(_ch0, 0, dest, destOffset * sizeof(float), cnt * sizeof(float));
}
else
{
// This is kinda annoying... if we're doing a downmix, we should technically only output a single channel
// The problem is, our caller is probably expecting stereo output. Grrrr....
// We use Buffer.BlockCopy here because we don't know dest's type, but do know it's big enough to do the copy
for (int i = 0; i < cnt; i++)
{
Buffer.BlockCopy(_ch0, i * sizeof(float), dest, destOffset * sizeof(float), sizeof(float));
++destOffset;
Buffer.BlockCopy(_ch1, i * sizeof(float), dest, destOffset * sizeof(float), sizeof(float));
++destOffset;
}
cnt *= 2;
}
return cnt;
}
return 0;
}
bool ValidateCRC()
{
var crc = 0xFFFFU;
// process the common bits...
UpdateCRC(_syncBits, 16, ref crc);
var apply = false;
switch (Layer)
{
case MpegLayer.LayerI:
apply = LayerIDecoder.GetCRC(this, ref crc);
break;
case MpegLayer.LayerII:
apply = LayerIIDecoder.GetCRC(this, ref crc);
break;
case MpegLayer.LayerIII:
apply = LayerIIIDecoder.GetCRC(this, ref crc);
break;
}
if (apply)
{
var checkCrc = ReadByte(4) << 8 | ReadByte(5);
return(checkCrc == crc);
}
return(true);
}
protected IFrameDecoder retrieveDecoder(Header header, Bitstream stream, int layer)
{
IFrameDecoder decoder = null;
// REVIEW: allow channel output selection type
// (LEFT, RIGHT, BOTH, DOWNMIX)
switch (layer)
{
case 3:
if (l3decoder == null)
{
l3decoder = new LayerIIIDecoder(stream,
header, filter1, filter2,
output, OutputChannels.Both);
}
decoder = l3decoder;
break;
case 2:
if (l2decoder == null)
{
l2decoder = new LayerIIDecoder();
l2decoder.create(stream,
header, filter1, filter2,
output, OutputChannels.Both);
}
decoder = l2decoder;
break;
case 1:
if (l1decoder == null)
{
l1decoder = new LayerIDecoder();
l1decoder.create(stream,
header, filter1, filter2,
output, OutputChannels.Both);
}
decoder = l1decoder;
break;
}
if (decoder == null)
{
throw new DecoderException(Errors.UNSUPPORTED_LAYER);
}
return(decoder);
}
int DecodeFrameImpl(IMpegFrame frame, Array dest, int destOffset)
{
frame.Reset();
Decoder.LayerDecoderBase curDecoder = null;
switch (frame.Layer)
{
case MpegLayer.LayerI:
if (_layerIDecoder == null)
{
_layerIDecoder = new Decoder.LayerIDecoder();
}
curDecoder = _layerIDecoder;
break;
case MpegLayer.LayerII:
if (_layerIIDecoder == null)
{
_layerIIDecoder = new Decoder.LayerIIDecoder();
}
curDecoder = _layerIIDecoder;
break;
case MpegLayer.LayerIII:
if (_layerIIIDecoder == null)
{
_layerIIIDecoder = new Decoder.LayerIIIDecoder();
}
curDecoder = _layerIIIDecoder;
break;
}
if (curDecoder != null)
{
curDecoder.SetEQ(_eqFactors);
curDecoder.StereoMode = StereoMode;
var cnt = curDecoder.DecodeFrame(frame, _ch0, _ch1);
if (frame.ChannelMode == MpegChannelMode.Mono)
{
Buffer.BlockCopy(_ch0, 0, dest, destOffset * sizeof(float), cnt * sizeof(float));
}
else
{
// This is kinda annoying... if we're doing a downmix, we should technically only output a single channel
// The problem is, our caller is probably expecting stereo output. Grrrr....
// We use Buffer.BlockCopy here because we don't know dest's type, but do know it's big enough to do the copy
for (int i = 0; i < cnt; i++)
{
Buffer.BlockCopy(_ch0, i * sizeof(float), dest, destOffset * sizeof(float), sizeof(float));
++destOffset;
Buffer.BlockCopy(_ch1, i * sizeof(float), dest, destOffset * sizeof(float), sizeof(float));
++destOffset;
}
cnt *= 2;
}
return(cnt);
}
return(0);
}
