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public static FlacRicePartition Read(StreamBuffer sb, int partitionNumber, int partitionOrder, int predictOrder, int blockSize, FlacResidualCodingMethod codingMethod)
{
FlacRicePartition ricePartition = new FlacRicePartition { _riceParameter = sb.ReadBigEndianInt32(), _codingMethod = codingMethod };
int riceParameter = ricePartition._riceParameter & ((codingMethod == FlacResidualCodingMethod.PartitionedRice) ? 0x1F : 0xF);
if (partitionOrder == 0)
ricePartition.Samples = blockSize - predictOrder;
else if (partitionNumber == 0)
ricePartition.Samples = (blockSize >> partitionOrder) - predictOrder;
else
ricePartition.Samples = blockSize >> partitionOrder;
ricePartition.Residuals = new int[ricePartition.Samples];
if ((riceParameter < 0xF) || ((codingMethod == FlacResidualCodingMethod.PartitionedRice2) && (riceParameter < 0x1F)))
{
for (int i = 0; i < ricePartition.Samples; i++)
{
long msbs = sb.ReadUnaryInt();
long lsbs = sb.ReadBigEndianInt32() & (0xFFFFFFFF >> (32 - riceParameter));
long value = (msbs << riceParameter) | lsbs;
ricePartition.Residuals[i] = ((value & 0x01) == 0x01) ? -((int)(value >> 1)) - 1 : (int)(value >> 1);
}
}
else
{
// residuals in unencoded form, sample size read from the next 5
// bits in the stream.
int size = sb.ReadBigEndianInt32();
for (int i = 0; i < ricePartition.Samples; i++)
ricePartition.Residuals[i] = sb.ReadBigEndianInt32();
}
return ricePartition;
}
public static unsafe void ProcessResidual(FlacBitReader reader, FlacFrameHeader header, FlacSubFrameData data,
int order, int partitionOrder, FlacResidualCodingMethod codingMethod)
{
data.Content.UpdateSize(partitionOrder);
bool isRice2 = codingMethod == FlacResidualCodingMethod.PartitionedRice2;
int riceParameterLength = isRice2 ? 5 : 4;
int escapeCode = isRice2 ? 31 : 15; //11111 : 1111
int samplesPerPartition;
int partitionCount = 1 << partitionOrder; //2^partitionOrder -> There will be 2^order partitions. -> "order" = partitionOrder in this case
int* residualBuffer = data.ResidualBuffer + order;
for (int p = 0; p < partitionCount; p++)
{
if (partitionOrder == 0)
samplesPerPartition = header.BlockSize - order;
else if (p > 0)
samplesPerPartition = header.BlockSize >> partitionOrder;
else
samplesPerPartition = (header.BlockSize >> partitionOrder) - order;
var riceParameter = reader.ReadBits(riceParameterLength);
data.Content.Parameters[p] = (int)riceParameter;
if (riceParameter >= escapeCode)
{
var raw = reader.ReadBits(5); //raw is always 5 bits (see ...(+5))
data.Content.RawBits[p] = (int)raw;
for (int i = 0; i < samplesPerPartition; i++)
{
int sample = reader.ReadBitsSigned((int)raw);
*(residualBuffer) = sample;
residualBuffer++;
}
}
else
{
ReadFlacRiceBlock(reader, samplesPerPartition, (int)riceParameter, residualBuffer);
residualBuffer += samplesPerPartition;
}
}
}
public FlacResidual(FlacBitReader reader, FlacFrameHeader header, FlacSubFrameData data, int order)
{
FlacResidualCodingMethod codingMethod = (FlacResidualCodingMethod)reader.ReadBits(2); // 2 Bit
if (codingMethod == FlacResidualCodingMethod.PartitionedRice || codingMethod == FlacResidualCodingMethod.PartitionedRice2)
{
int partitionOrder = (int)reader.ReadBits(4); //"Partition order." see https://xiph.org/flac/format.html#partitioned_rice and https://xiph.org/flac/format.html#partitioned_rice2
FlacPartitionedRice.ProcessResidual(reader, header, data, order, partitionOrder, codingMethod);
#if FLAC_DEBUG
CodingMethodMethod = codingMethod;
PartitionOrder = partitionOrder;
#endif
}
else
{
throw new FlacException("Not supported RICE-Coding-Method. Stream unparseable!", FlacLayer.SubFrame);
}
}
