private bool DecodeHuffmanCode(int ch, int gr, int endpos)
{
int idx = 0;
// Reading and decoding BigValue.
int Region1Start, Region2Start;
GranuleInfo f_granule = frame.granule[ch, gr];
if (f_granule.BlockType == 0)
{
Region1Start = ScfBandIndex[frame.FrequencyIndex].
LongBlock[f_granule.Region0Count + 1];
Region2Start = ScfBandIndex[frame.FrequencyIndex].
LongBlock[f_granule.Region0Count + f_granule.Region1Count + 2];
}
else
{
Region1Start = 36;
Region2Start = 576;
}
for (; idx <= 576 - 2 && idx < f_granule.BigValues * 2
; idx += 2)
{
int tbl;
// Region0
if (idx < Region1Start)
{
tbl = f_granule.GetTableSelect(0);
}
// Region1
else if (idx < Region2Start)
{
tbl = f_granule.GetTableSelect(1);
}
// Region2
else
{
tbl = f_granule.GetTableSelect(2);
}
LookupHuffman(ch, tbl, idx);
}
// Reading and decoding Count1
for ( ; (idx <= 576 - 4) && (bs.PositionBit < endpos); idx += 4)
{
LookupHuffmanQ(ch, f_granule.Count1TableSelect, idx);
}
for (; idx < 576; idx++)
{
_is[ch, idx] = 0;
}
return(true);
}
public ToyMP3Frame()
{
// initialize
CRC_check = 0;
for (int i = 0; i < 2; i++)
{
for (int j = 0; j < 2; j++)
{
granule[i, j] = new GranuleInfo();
}
}
}
private void Dequantize(int ch, int gr)
{
GranuleInfo _gr = frame.granule[ch, gr];
double Gain = 0.25 * (_gr.GlobalGain - 210.0);
for (int i = 0; i < 576; i++)
{
if (SampleMap[ch, i].BlockType == BLOCK_SHORT)
{
Gain -= -2.0 * _gr.GetSubblockGain(SampleMap[ch, i].Subblock);
}
xr[ch, SampleMap[ch, i].OrderIndex] = _is[ch, i] *
Math.Pow(Math.Abs(_is[ch, i]), 1.0 / 3.0) *
Math.Pow(2.0, Gain - SampleMap[ch, i].Scale);
}
}
private void Antialias(int ch, int gr)
{
if (!AntialiasInitializedFlag)
{
InitAntialias();
AntialiasInitializedFlag = true;
}
GranuleInfo _gr = frame.granule[ch, gr];
if (_gr.IsShortBlock)
{
return;
}
int nl;
if (_gr.IsLongBlock)
{
nl = 31;
}
else
{
nl = 1;
}
for (int k = 0; k < nl; k++)
{
for (int i = 0; i < 8; i++)
{
double a0 = xr[ch, (k * 18) + 18 + i];
double b0 = xr[ch, (k * 18) + 17 - i];
xr[ch, (k * 18) + 18 + i] = a0 * g_cs[i] + b0 * g_ca[i];
xr[ch, (k * 18) + 17 - i] = b0 * g_cs[i] - a0 * g_ca[i];
}
}
}
private void InverseMDCTSynthesys(int ch, int gr)
{
// Initialize
if (!InversedMDCTInitializedFlag)
{
InitIMDCT();
InversedMDCTInitializedFlag = true;
}
GranuleInfo _gr = frame.granule[ch, gr];
int LongSubbandNum = 0;
int WindowTypeLong = 0;
if (_gr.IsLongBlock)
{
LongSubbandNum = 32;
WindowTypeLong = _gr.BlockType;
}
else if (_gr.IsShortBlock)
{
LongSubbandNum = 0;
WindowTypeLong = -1;
}
else if (_gr.IsMixedBlock)
{
LongSubbandNum = 2;
WindowTypeLong = 0;
}
int _Subband = 0;
int _Index = 0;
// Long (and mixed) Block
for (_Subband = 0; _Subband < LongSubbandNum; _Subband++)
{
double[] Rawout = new double[36];
for (int i = 0; i < 36; i++)
{
double _Sum = 0.0;
for (int j = 0; j < 18; j++)
{
_Sum += xr[ch, j + _Subband * 18] * Math.Cos
(
Math.PI / 72.0 * (2.0 * i + 19.0) * (2.0 * j + 1.0)
);
}
Rawout[i] = _Sum * SineWindow[WindowTypeLong, i];
}
// Combine width last granule and saving;
for (int ss = 0; ss < 18; ss++)
{
// First half of data + Second half of prev data.
pfb[ch, _Index] = Rawout[ss] + ImdctPrevRawout[ch, _Index];
// Keep second half of data for next granule.
ImdctPrevRawout[ch, _Index] = Rawout[ss + 18];
_Index++;
}
}
// ShortBlock
for (; _Subband < 32; _Subband++)
{
double[] Rawout = new double[36];
for (int _Subblock = 0; _Subblock < 3; _Subblock++)
{
double[] RawoutTmp = new double[12];
for (int i = 0; i < 12; i++)
{
double _Sum = 0;
for (int j = 0; j < 6; j++)
{
_Sum += xr[ch, _Subband *18 + j * 3 + _Subblock] *
Math.Cos(Math.PI / 24.0 * (2.0 * i + 7.0) * (2.0 * j + 1.0));
}
RawoutTmp[i] = _Sum * SineWindow[2, i];
}
for (int i = 0; i < 12; i++)
{
Rawout[6 * _Subblock + i + 6] += RawoutTmp[i];
}
}
for (int ss = 0; ss < 18; ss++)
{
pfb[ch, _Index] = Rawout[ss] + ImdctPrevRawout[ch, _Index];
ImdctPrevRawout[ch, _Index] = Rawout[ss + 18];
_Index++;
}
}
}
private void CreateSampleMap(int ch, int gr)
{
int idx = 0;
GranuleInfo _gr = frame.granule[ch, gr];
// Short Block
if (_gr.IsShortBlock)
{
int[] ScfbIdx = ScfBandIndex[frame.FrequencyIndex].ShortBlock;
for (int _sbi = 0; _sbi < 13; _sbi++)
{
int idx_s = idx;
for (int _sub = 0; _sub < 3; _sub++)
{
int CriticalBandWidth = ScfbIdx[_sbi + 1] - ScfbIdx[_sbi];
for (int i = 0; i < CriticalBandWidth; i++)
{
SampleMap[ch, idx] = new Sample();
SampleMap[ch, idx].BlockType = BLOCK_SHORT;
SampleMap[ch, idx].Subblock = _sub;
SampleMap[ch, idx].Scale =
0.5 * (_gr.ScalefacScale + 1.0) *
Scf[ch, gr].ShortBlock[_sub, _sbi];
SampleMap[ch, idx].OrderIndex =
3 * ((idx - idx_s) % CriticalBandWidth) +
(idx - idx_s) / CriticalBandWidth + idx_s;
idx++;
}
}
}
}
// Long Block
else if (_gr.IsLongBlock)
{
int[] ScfbIdx = ScfBandIndex[frame.FrequencyIndex].LongBlock;
int Scfb = 0;
for (int i = 0; i < 576; i++)
{
SampleMap[ch, idx] = new Sample();
SampleMap[ch, idx].BlockType = BLOCK_LONG;
SampleMap[ch, idx].Subblock = 0;
SampleMap[ch, idx].OrderIndex = idx;
if (idx >= ScfbIdx[Scfb + 1])
{
Scfb++;
}
int _Scf = Scf[ch, gr].LongBlock[Scfb];
if (_gr.PreFlag == 1)
{
_Scf += PreemphasisTable[Scfb];
}
SampleMap[ch, idx].Scale =
0.5 * (_gr.ScalefacScale + 1.0) * _Scf;
idx++;
}
}
// MixedBlock
else
{
// LongBlock sample
int[] ScfbIdx = ScfBandIndex[frame.FrequencyIndex].LongBlock;
int Scfb = 0;
for (int i = 0; i < 36; i++)
{
SampleMap[ch, idx] = new Sample();
SampleMap[ch, idx].BlockType = BLOCK_LONG;
SampleMap[ch, idx].Subblock = 0;
SampleMap[ch, idx].OrderIndex = idx;
if (idx >= ScfbIdx[Scfb + 1])
{
Scfb++;
}
int _Scf = Scf[ch, gr].LongBlock[Scfb];
if (_gr.PreFlag == 1)
{
_Scf += PreemphasisTable[Scfb];
}
SampleMap[ch, idx].Scale =
0.5 * (_gr.ScalefacScale + 1.0) * _Scf;
idx++;
}
// Short Block Samples
ScfbIdx = ScfBandIndex[frame.FrequencyIndex].ShortBlock;
for (Scfb = 3; Scfb < 13; Scfb++)
{
int idx_s = idx;
for (int _sub = 0; _sub < 3; _sub++)
{
int CriticalBandWidth =
ScfbIdx[Scfb + 1] - ScfbIdx[Scfb];
for (int i = 0; i < CriticalBandWidth; i++)
{
SampleMap[ch, idx].BlockType = BLOCK_SHORT;
SampleMap[ch, idx].Subblock = _sub;
int _Scf = Scf[ch, gr].ShortBlock[_sub, Scfb];
SampleMap[ch, idx].Scale =
0.5 * (_gr.ScalefacScale + 1.0) * _Scf;
SampleMap[ch, idx].OrderIndex =
3 * ((idx - idx_s) % CriticalBandWidth) +
(idx - idx_s) / CriticalBandWidth + idx_s;
idx++;
}
}
}
}
}
private void DecodeScalefactor(GranuleInfo granule, int ch, int gr)
{
int Slen1 = granule.Slen[0];
int Slen2 = granule.Slen[1];
// Mixed Block
if (granule.IsMixedBlock)
{
for (int sfb = 0; sfb < 8; sfb++)
{
Scf[ch, gr].LongBlock[sfb] = bs.GetByInt(Slen1);
}
for (int sfb = 3; sfb < 6; sfb++)
{
for (int w = 0; w < 3; w++)
{
Scf[ch, gr].ShortBlock[w, sfb] = bs.GetByInt(Slen1);
}
}
for (int sfb = 6; sfb < 12; sfb++)
{
for (int w = 0; w < 3; w++)
{
Scf[ch, gr].ShortBlock[w, sfb] = bs.GetByInt(Slen2);
}
}
}
// Short Block
else if (granule.IsShortBlock)
{
for (int sfb = 0; sfb < 6; sfb++)
{
for (int w = 0; w < 3; w++)
{
Scf[ch, gr].ShortBlock[w, sfb] = bs.GetByInt(Slen1);
}
}
for (int sfb = 6; sfb < 12; sfb++)
{
for (int w = 0; w < 3; w++)
{
Scf[ch, gr].ShortBlock[w, sfb] = bs.GetByInt(Slen2);
}
}
}
// Long Block
else if (granule.IsLongBlock)
{
// In case granule0,
// without exception, data should be taken from bitstream.
if (gr == 0)
{
for (int sfb = 0; sfb < 11; sfb++)
{
Scf[ch, gr].LongBlock[sfb] = bs.GetByInt(Slen1);
}
for (int sfb = 11; sfb < 21; sfb++)
{
Scf[ch, gr].LongBlock[sfb] = bs.GetByInt(Slen2);
}
}
else
{
// When processing granule1 and SCFSI is 1,
// sdalefactor will shared with granule0.
// Else, scalefactor should be got from bitstream.
if (frame.GetScfsi(ch, 0) == 1)
{
for (int sfb = 0; sfb < 6; sfb++)
{
Scf[ch, gr].LongBlock[sfb] = Scf[ch, 0].LongBlock[sfb];
}
}
else
{
for (int sfb = 0; sfb < 6; sfb++)
{
Scf[ch, gr].LongBlock[sfb] = bs.GetByInt(Slen1);
}
}
if (frame.GetScfsi(ch, 1) == 1)
{
for (int sfb = 6; sfb < 11; sfb++)
{
Scf[ch, gr].LongBlock[sfb] = Scf[ch, 0].LongBlock[sfb];
}
}
else
{
for (int sfb = 6; sfb < 11; sfb++)
{
Scf[ch, gr].LongBlock[sfb] = bs.GetByInt(Slen1);
}
}
if (frame.GetScfsi(ch, 2) == 1)
{
for (int sfb = 11; sfb < 16; sfb++)
{
Scf[ch, gr].LongBlock[sfb] = Scf[ch, 0].LongBlock[sfb];
}
}
else
{
for (int sfb = 11; sfb < 16; sfb++)
{
Scf[ch, gr].LongBlock[sfb] = bs.GetByInt(Slen2);
}
}
if (frame.GetScfsi(ch, 3) == 1)
{
for (int sfb = 16; sfb < 21; sfb++)
{
Scf[ch, gr].LongBlock[sfb] = Scf[ch, 0].LongBlock[sfb];
}
}
else
{
for (int sfb = 16; sfb < 21; sfb++)
{
Scf[ch, gr].LongBlock[sfb] = bs.GetByInt(Slen2);
}
}
}
}
}