private static void DecodeFrame(BitReader reader, Frame frame)
{
Unpack.UnpackFrame(reader, frame);
foreach (Block block in frame.Blocks)
{
Quantization.DequantizeSpectra(block);
Stereo.ApplyIntensityStereo(block);
Quantization.ScaleSpectrum(block);
BandExtension.ApplyBandExtension(block);
ImdctBlock(block);
}
}
private static void ReadExtensionParams(BitReader reader, Block block)
{
// ReSharper disable once RedundantAssignment
int bexBand = 0;
if (block.BandExtensionEnabled)
{
BandExtension.GetBexBandInfo(out bexBand, out _, out _, block.QuantizationUnitCount);
if (block.BlockType == BlockType.Stereo)
{
ReadHeader(block.Channels[1]);
}
else
{
reader.Position += 1;
}
}
block.HasExtensionData = reader.ReadBool();
if (!block.HasExtensionData)
{
return;
}
if (!block.BandExtensionEnabled)
{
block.BexMode = reader.ReadInt(2);
block.BexDataLength = reader.ReadInt(5);
reader.Position += block.BexDataLength;
return;
}
ReadHeader(block.Channels[0]);
block.BexDataLength = reader.ReadInt(5);
if (block.BexDataLength <= 0)
{
return;
}
int bexDataEnd = reader.Position + block.BexDataLength;
ReadData(block.Channels[0]);
if (block.BlockType == BlockType.Stereo)
{
ReadData(block.Channels[1]);
}
// Make sure we didn't read too many bits
if (reader.Position > bexDataEnd)
{
throw new InvalidDataException();
}
void ReadHeader(Channel channel)
{
int bexMode = reader.ReadInt(2);
channel.BexMode = bexBand > 2 ? bexMode : 4;
channel.BexValueCount = BexEncodedValueCounts[channel.BexMode][bexBand];
}
void ReadData(Channel channel)
{
for (int i = 0; i < channel.BexValueCount; i++)
{
int dataLength = BexDataLengths[channel.BexMode][bexBand][i];
channel.BexValues[i] = reader.ReadInt(dataLength);
}
}
}
