public unsafe static FlacSubFrameBase GetSubFrame(FlacBitReader reader, FlacSubFrameData data, FlacFrameHeader header, int bitsPerSample)
{
int wastedBits = 0, order;
uint firstByte = reader.ReadBits(8);
if ((firstByte & 0x80) != 0) //Zero bit padding, to prevent sync-fooling string of 1s
{
Debug.WriteLine("Flacdecoder subframe-header got no zero-bit padding.");
return(null);
}
bool hasWastedBits = (firstByte & 1) != 0; //Wasted bits-per-sample' flag
if (hasWastedBits)
{
int k = (int)reader.ReadUnary();
wastedBits = k + 1; //"k-1" follows -> add 1
bitsPerSample -= wastedBits;
}
FlacSubFrameBase subFrame;
var subframeType = (firstByte & 0x7E) >> 1; //0111 1110
if (subframeType == 0) //000000
{
subFrame = new FlacSubFrameConstant(reader, header, data, bitsPerSample);
}
else if (subframeType == 1) //000001
{
subFrame = new FlacSubFrameVerbatim(reader, header, data, bitsPerSample);
}
else if ((subframeType & 0x20) != 0) //100000 = 0x20
{
order = (int)(subframeType & 0x1F) + 1;
subFrame = new FlacSubFrameLPC(reader, header, data, bitsPerSample, order);
}
else if ((subframeType & 0x08) != 0) //001000 = 0x08
{
order = (int)(subframeType & 0x07);
if (order > 4)
{
return(null);
}
subFrame = new FlacSubFrameFixed(reader, header, data, bitsPerSample, order);
}
else
{
Debug.WriteLine(String.Format("Invalid Flac-SubframeType. SubframeType: 0x{0:x}.", subframeType));
return(null);
}
if (hasWastedBits)
{
int *destination = data.DestinationBuffer;
for (int i = 0; i < header.BlockSize; i++)
{
*(destination++) <<= wastedBits;
}
}
#if FLAC_DEBUG
subFrame.WastedBits = wastedBits;
#endif
return(subFrame);
}
private unsafe bool ParseHeader(ref byte *headerBuffer, FlacMetadataStreamInfo streamInfo)
{
const string loggerLocation = "FlacFrameHeader.ParseHeader(byte*, FlacMetadataStreamInfo)";
int val;
if (headerBuffer[0] == 0xFF && headerBuffer[1] >> 1 == 0x7C) //sync bits
{
if ((headerBuffer[1] & 0x02) != 0)
{
Error("Invalid FlacFrame. Reservedbit_0 is 1", loggerLocation);
return(false);
}
byte * __headerbufferPtr = headerBuffer;
FlacBitReader reader = new FlacBitReader(__headerbufferPtr, 0);
#region blocksize
//blocksize
val = headerBuffer[2] >> 4;
int blocksize = -1;
if (val == 0)
{
Error("Invalid Blocksize value: 0", loggerLocation);
return(false);
}
if (val == 1)
{
blocksize = 192;
}
else if (val >= 2 && val <= 5)
{
blocksize = 576 << (val - 2);
}
else if (val == 6 || val == 7)
{
_blocksizeHint = val;
}
else if (val >= 8 && val <= 15)
{
blocksize = 256 << (val - 8);
}
else
{
Error("Invalid Blocksize value: " + val, loggerLocation);
return(false);
}
BlockSize = blocksize;
#endregion blocksize
#region samplerate
//samplerate
val = headerBuffer[2] & 0x0F;
int sampleRate = -1;
if (val == 0)
{
if (streamInfo != null)
{
sampleRate = streamInfo.SampleRate;
}
else
{
Error("Missing Samplerate. Samplerate Index = 0 && streamInfoMetaData == null.", loggerLocation);
return(false);
}
}
else if (val >= 1 && val <= 11)
{
sampleRate = FlacConstant.SampleRateTable[val];
}
else if (val >= 12 && val <= 14)
{
_sampleRateHint = val;
}
else
{
Error("Invalid SampleRate value: " + val, loggerLocation);
return(false);
}
SampleRate = sampleRate;
#endregion samplerate
#region channels
val = headerBuffer[3] >> 4; //cc: unsigned
int channels;
if ((val & 8) != 0)
{
channels = 2;
if ((val & 7) > 2 || (val & 7) < 0)
{
Error("Invalid ChannelAssignment", loggerLocation);
return(false);
}
ChannelAssignment = (ChannelAssignment)((val & 7) + 1);
}
else
{
channels = val + 1;
ChannelAssignment = ChannelAssignment.Independent;
}
Channels = channels;
#endregion channels
#region bitspersample
val = (headerBuffer[3] & 0x0E) >> 1;
int bitsPerSample;
if (val == 0)
{
if (streamInfo != null)
{
bitsPerSample = streamInfo.BitsPerSample;
}
else
{
Error("Missing BitsPerSample. Index = 0 && streamInfoMetaData == null.", loggerLocation);
return(false);
}
}
else if (val == 3 || val >= 7 || val < 0)
{
Error("Invalid BitsPerSampleIndex", loggerLocation);
return(false);
}
else
{
bitsPerSample = FlacConstant.BitPerSampleTable[val];
}
BitsPerSample = bitsPerSample;
#endregion bitspersample
if ((headerBuffer[3] & 0x01) != 0) // reserved bit -> 0
{
Error("Invalid FlacFrame. Reservedbit_1 is 1", loggerLocation);
return(false);
}
reader.ReadBits(32); //skip the first 4 bytes since they got already processed
//BYTE 4
#region utf8
//variable blocksize
if ((headerBuffer[1] & 0x01) != 0 ||
(streamInfo != null && streamInfo.MinBlockSize != streamInfo.MaxBlockSize))
{
ulong samplenumber;
if (reader.ReadUTF8_64(out samplenumber) && samplenumber != ulong.MaxValue)
{
BlockingStrategy = BlockingStrategy.VariableBlockSize;
SampleNumber = (long)samplenumber;
}
else
{
Error("Invalid UTF8 Samplenumber coding.", loggerLocation);
return(false);
}
}
else //fixed blocksize
{
uint framenumber;
if (reader.ReadUTF8_32(out framenumber) && framenumber != uint.MaxValue)
{
BlockingStrategy = BlockingStrategy.FixedBlockSize;
FrameNumber = (int)framenumber;
}
else
{
Error("Invalid UTF8 Framenumber coding.", loggerLocation);
return(false);
}
}
#endregion utf8
#region read hints
//blocksize am ende des frameheaders
if (_blocksizeHint != 0)
{
val = (int)reader.ReadBits(8);
if (_blocksizeHint == 7)
{
val = (val << 8) | (int)reader.ReadBits(8);
}
BlockSize = val + 1;
}
//samplerate
if (_sampleRateHint != 0)
{
val = (int)reader.ReadBits(8);
if (_sampleRateHint != 12)
{
val = (val << 8) | (int)reader.ReadBits(8);
}
if (_sampleRateHint == 12)
{
SampleRate = val * 1000;
}
else if (_sampleRateHint == 13)
{
SampleRate = val;
}
else
{
SampleRate = val * 10;
}
}
#endregion read hints
if (DoCrc)
{
var crc8 = Utils.CRC8.Instance.CalcCheckSum(reader.Buffer, 0, reader.Position);
Crc8 = (byte)reader.ReadBits(8);
if (Crc8 != crc8)
{
Error("CRC8 missmatch", loggerLocation);
return(false);
}
}
else
{
Crc8 = (byte)reader.ReadBits(8);
}
headerBuffer += reader.Position;
return(true);
}
Error("Invalid Syncbits", loggerLocation);
return(false);
}
public unsafe FlacSubFrameLPC(FlacBitReader reader, FlacFrameHeader header, FlacSubFrameData data, int bitsPerSample, int order)
: base(header)
{
var warmup = new int[order];
for (int i = 0; i < order; i++)
{
warmup[i] = data.ResidualBuffer[i] = reader.ReadBitsSigned(bitsPerSample);
}
int coefPrecision = (int)reader.ReadBits(4);
if (coefPrecision == 0x0F)
{
throw new FlacException("Invalid \"quantized linear predictor coefficients' precision in bits\" was invalid. Must not be 0x0F.",
FlacLayer.SubFrame);
}
coefPrecision += 1;
int shiftNeeded = reader.ReadBitsSigned(5);
if (shiftNeeded < 0)
{
throw new FlacException("'\"Quantized linear predictor coefficient shift needed in bits\" was negative.", FlacLayer.SubFrame);
}
var q = new int[order];
for (int i = 0; i < order; i++)
{
q[i] = reader.ReadBitsSigned(coefPrecision);
}
//decode the residual
var residual = new FlacResidual(reader, header, data, order);
for (int i = 0; i < order; i++)
{
data.DestinationBuffer[i] = data.ResidualBuffer[i];
}
int *residualBuffer0 = data.ResidualBuffer + order;
int *destinationBuffer0 = data.DestinationBuffer + order;
int blockSizeToProcess = header.BlockSize - order;
if (bitsPerSample + coefPrecision + Log2(order) <= 32)
{
RestoreLPCSignal32(residualBuffer0, destinationBuffer0, blockSizeToProcess, order, q, shiftNeeded);
}
else
{
RestoreLPCSignal64(residualBuffer0, destinationBuffer0, blockSizeToProcess, order, q, shiftNeeded);
}
#if FLAC_DEBUG
QLPCoeffPrecision = coefPrecision;
LPCShiftNeeded = shiftNeeded;
Warmup = warmup;
Residual = residual;
QLPCoeffs = q;
#endif
}