internal static VorbisMode Init(VorbisStreamDecoder vorbis, DataPacket packet)
{
var mode = new VorbisMode(vorbis);
mode.BlockFlag = packet.ReadBit();
mode.WindowType = (int)packet.ReadBits(16);
mode.TransformType = (int)packet.ReadBits(16);
var mapping = (int)packet.ReadBits(8);
if (mode.WindowType != 0 || mode.TransformType != 0 || mapping >= vorbis.Maps.Length)
{
throw new InvalidOperationException();
}
mode.Mapping = vorbis.Maps[mapping];
mode.BlockSize = mode.BlockFlag ? vorbis.Block1Size : vorbis.Block0Size;
// now pre-calc the window(s)...
if (mode.BlockFlag)
{
// long block
mode._windows = new float[4][];
mode._windows[0] = new float[vorbis.Block1Size];
mode._windows[1] = new float[vorbis.Block1Size];
mode._windows[2] = new float[vorbis.Block1Size];
mode._windows[3] = new float[vorbis.Block1Size];
}
else
{
// short block
mode._windows = new float[1][];
mode._windows[0] = new float[vorbis.Block0Size];
}
mode.CalcWindows();
return(mode);
}
bool UnpackPacket(DataPacket packet)
{
// make sure we're on an audio packet
if (packet.ReadBit())
{
// we really can't do anything... count the bits as waste
return(false);
}
// get mode and prev/next flags
var modeBits = _modeFieldBits;
_mode = Modes[(int)packet.ReadBits(_modeFieldBits)];
if (_mode.BlockFlag)
{
_prevFlag = packet.ReadBit();
_nextFlag = packet.ReadBit();
modeBits += 2;
}
else
{
_prevFlag = _nextFlag = false;
}
if (packet.IsShort)
{
return(false);
}
var startBits = packet.BitsRead;
var halfBlockSize = _mode.BlockSize / 2;
// read the noise floor data (but don't decode yet)
for (int i = 0; i < _channels; i++)
{
_floorData[i] = _mode.Mapping.ChannelSubmap[i].Floor.UnpackPacket(packet, _mode.BlockSize, i);
_noExecuteChannel[i] = !_floorData[i].ExecuteChannel;
// go ahead and clear the residue buffers
Array.Clear(_residue[i], 0, halfBlockSize);
}
// make sure we handle no-energy channels correctly given the couplings...
foreach (var step in _mode.Mapping.CouplingSteps)
{
if (_floorData[step.Angle].ExecuteChannel || _floorData[step.Magnitude].ExecuteChannel)
{
_floorData[step.Angle].ForceEnergy = true;
_floorData[step.Magnitude].ForceEnergy = true;
}
}
var floorBits = packet.BitsRead - startBits;
startBits = packet.BitsRead;
foreach (var subMap in _mode.Mapping.Submaps)
{
for (int j = 0; j < _channels; j++)
{
if (_mode.Mapping.ChannelSubmap[j] != subMap)
{
_floorData[j].ForceNoEnergy = true;
}
}
var rTemp = subMap.Residue.Decode(packet, _noExecuteChannel, _channels, _mode.BlockSize);
for (int c = 0; c < _channels; c++)
{
var r = _residue[c];
var rt = rTemp[c];
for (int i = 0; i < halfBlockSize; i++)
{
r[i] += rt[i];
}
}
}
_glueBits += 1;
_modeBits += modeBits;
_floorBits += floorBits;
_resBits += packet.BitsRead - startBits;
_wasteBits += 8 * packet.Length - packet.BitsRead;
_packetCount += 1;
return(true);
}
bool LoadBooks(DataPacket packet)
{
if (!packet.ReadBytes(7).SequenceEqual(new byte[] { 0x05, 0x76, 0x6f, 0x72, 0x62, 0x69, 0x73 }))
{
return(false);
}
if (!_pagesSeen.Contains((_lastPageSeen = packet.PageSequenceNumber)))
{
_pagesSeen.Add(_lastPageSeen);
}
var bits = packet.BitsRead;
_glueBits += packet.BitsRead;
// get books
Books = new VorbisCodebook[packet.ReadByte() + 1];
for (int i = 0; i < Books.Length; i++)
{
Books[i] = VorbisCodebook.Init(this, packet, i);
}
_bookBits += packet.BitsRead - bits;
bits = packet.BitsRead;
// get times
Times = new VorbisTime[(int)packet.ReadBits(6) + 1];
for (int i = 0; i < Times.Length; i++)
{
Times[i] = VorbisTime.Init(this, packet);
}
_timeHdrBits += packet.BitsRead - bits;
bits = packet.BitsRead;
// get floor
Floors = new VorbisFloor[(int)packet.ReadBits(6) + 1];
for (int i = 0; i < Floors.Length; i++)
{
Floors[i] = VorbisFloor.Init(this, packet);
}
_floorHdrBits += packet.BitsRead - bits;
bits = packet.BitsRead;
// get residue
Residues = new VorbisResidue[(int)packet.ReadBits(6) + 1];
for (int i = 0; i < Residues.Length; i++)
{
Residues[i] = VorbisResidue.Init(this, packet);
}
_resHdrBits += packet.BitsRead - bits;
bits = packet.BitsRead;
// get map
Maps = new VorbisMapping[(int)packet.ReadBits(6) + 1];
for (int i = 0; i < Maps.Length; i++)
{
Maps[i] = VorbisMapping.Init(this, packet);
}
_mapHdrBits += packet.BitsRead - bits;
bits = packet.BitsRead;
// get mode settings
Modes = new VorbisMode[(int)packet.ReadBits(6) + 1];
for (int i = 0; i < Modes.Length; i++)
{
Modes[i] = VorbisMode.Init(this, packet);
}
_modeHdrBits += packet.BitsRead - bits;
// check the framing bit
if (!packet.ReadBit())
{
throw new InvalidOperationException();
}
++_glueBits;
_wasteHdrBits += 8 * packet.Length - packet.BitsRead;
_modeFieldBits = Utils.ilog(Modes.Length - 1);
return(true);
}