private void decodeSpectralData(BitStream inStream)
{
Array.Clear(data, 0, data.Length);
int maxSFB = info.getMaxSFB();
int windowGroups = info.getWindowGroupCount();
int[] offsets = info.getSWBOffsets();
int[] buf = new int[4];
int sfb, j, k, w, hcb, off, width, num;
int groupOff = 0, idx = 0;
for (int g = 0; g < windowGroups; g++)
{
int groupLen = info.getWindowGroupLength(g);
for (sfb = 0; sfb < maxSFB; sfb++, idx++)
{
hcb = sfbCB[idx];
off = groupOff + offsets[sfb];
width = offsets[sfb + 1] - offsets[sfb];
if (hcb == ZERO_HCB || hcb == INTENSITY_HCB || hcb == INTENSITY_HCB2)
{
for (w = 0; w < groupLen; w++, off += 128)
{
Array.Clear(data, off, width);
}
}
else if (hcb == NOISE_HCB)
{
//apply PNS: fill with random values
for (w = 0; w < groupLen; w++, off += 128)
{
float energy = 0;
for (k = 0; k < width; k++)
{
randomState *= 1664525 + 1013904223;
data[off + k] = randomState;
energy += data[off + k] * data[off + k];
}
float scale = (float)(scaleFactors[idx] / Math.Sqrt(energy));
for (k = 0; k < width; k++)
{
data[off + k] *= scale;
}
}
}
else
{
for (w = 0; w < groupLen; w++, off += 128)
{
num = (hcb >= FIRST_PAIR_HCB) ? 2 : 4;
for (k = 0; k < width; k += num)
{
Huffman.decodeSpectralData(inStream, hcb, buf, 0);
//inverse quantization & scaling
for (j = 0; j < num; j++)
{
data[off + k + j] = (buf[j] > 0) ? IQ_TABLE[buf[j]] : -IQ_TABLE[-buf[j]];
data[off + k + j] *= scaleFactors[idx];
}
}
}
}
}
groupOff += groupLen << 7;
}
}
void decode(BitStream inStream, DecoderConfig conf)
{
couplingPoint = 2 * inStream.readBit();
coupledCount = inStream.readBits(3);
int gainCount = 0;
for (int i = 0; i <= coupledCount; i++)
{
gainCount++;
channelPair[i] = inStream.readBool();
idSelect[i] = inStream.readBits(4);
if (channelPair[i])
{
chSelect[i] = inStream.readBits(2);
if (chSelect[i] == 3)
{
gainCount++;
}
}
else
{
chSelect[i] = 2;
}
}
couplingPoint += inStream.readBit();
couplingPoint |= (couplingPoint >> 1);
bool sign = inStream.readBool();
double scale = CCE_SCALE[inStream.readBits(2)];
ics.decode(inStream, false, conf);
ICSInfo info = ics.getInfo();
int windowGroupCount = info.getWindowGroupCount();
int maxSFB = info.getMaxSFB();
//TODO:
int[,] sfbCB = null;//ics.getSectionData().getSfbCB();
for (int i = 0; i < gainCount; i++)
{
int idx = 0;
int cge = 1;
int xg = 0;
float gainCache = 1.0f;
if (i > 0)
{
cge = couplingPoint == 2 ? 1 : inStream.readBit();
xg = cge == 0 ? 0 : Huffman.decodeScaleFactor(inStream) - 60;
gainCache = (float)Math.Pow(scale, -xg);
}
if (couplingPoint == 2)
{
gain[i, 0] = gainCache;
}
else
{
for (int g = 0; g < windowGroupCount; g++)
{
for (int sfb = 0; sfb < maxSFB; sfb++, idx++)
{
if (sfbCB[g, sfb] != ZERO_HCB)
{
if (cge == 0)
{
int t = Huffman.decodeScaleFactor(inStream) - 60;
if (t != 0)
{
int s = 1;
t = xg += t;
if (!sign)
{
s -= 2 * (t & 0x1);
t >>= 1;
}
gainCache = (float)(Math.Pow(scale, -t) * s);
}
}
gain[i, idx] = gainCache;
}
}
}
}
}
}
// private void decodePulseData(BitStream in) throws AACException {
// pulseCount = in.readBits(2)+1;
// pulseStartSWB = in.readBits(6);
// if(pulseStartSWB>=info.getSWBCount()) throw new AACException("pulse SWB out of range: "+pulseStartSWB+" > "+info.getSWBCount());
// if(pulseOffset==null||pulseCount!=pulseOffset.Length) {
// //only reallocate if needed
// pulseOffset = new int[pulseCount];
// pulseAmp = new int[pulseCount];
// }
// pulseOffset[0] = info.getSWBOffsets()[pulseStartSWB];
// pulseOffset[0] += in.readBits(5);
// pulseAmp[0] = in.readBits(4);
// for(int i = 1; i<pulseCount; i++) {
// pulseOffset[i] = in.readBits(5)+pulseOffset[i-1];
// if(pulseOffset[i]>1023) throw new AACException("pulse offset out of range: "+pulseOffset[0]);
// pulseAmp[i] = in.readBits(4);
// }
// }
public void decodeScaleFactors(BitStream inStream)
{
int windowGroups = info.getWindowGroupCount();
int maxSFB = info.getMaxSFB();
//0: spectrum, 1: noise, 2: intensity
int[] offset = { globalGain, globalGain - 90, 0 };
int tmp;
bool noiseFlag = true;
int sfb, idx = 0;
for (int g = 0; g < windowGroups; g++)
{
for (sfb = 0; sfb < maxSFB;)
{
int end = sectEnd[idx];
switch (sfbCB[idx])
{
case ZERO_HCB:
{
for (; sfb < end; sfb++, idx++)
{
scaleFactors[idx] = 0;
}
} break;
case INTENSITY_HCB:
case INTENSITY_HCB2:
{
for (; sfb < end; sfb++, idx++)
{
offset[2] += Huffman.decodeScaleFactor(inStream) - SF_DELTA;
tmp = Math.Min(Math.Max(offset[2], -155), 100);
scaleFactors[idx] = SCALEFACTOR_TABLE[-tmp + SF_OFFSET];
}
} break;
case NOISE_HCB:
{
throw new NotImplementedException();
//for (; sfb < end; sfb++, idx++)
//{
// if (noiseFlag)
// {
// offset[1] += inStream.readBits(9) - 256;
// noiseFlag = false;
// }
// else offset[1] += Huffman.decodeScaleFactor(inStream) - SF_DELTA;
// tmp = Math.min(Math.max(offset[1], -100), 155);
// scaleFactors[idx] = -SCALEFACTOR_TABLE[tmp + SF_OFFSET];
//}
} break;
default:
{
for (; sfb < end; sfb++, idx++)
{
offset[0] += Huffman.decodeScaleFactor(inStream) - SF_DELTA;
if (offset[0] > 255)
{
throw new AACException("scalefactor out of range: " + offset[0]);
}
scaleFactors[idx] = SCALEFACTOR_TABLE[offset[0] - 100 + SF_OFFSET];
}
} break;
}
}
}
}
