/// <summary>Decode the given input bits.</summary>
/// <remarks>Decode the given input bits.</remarks>
/// <param name="bits">- Speex bits buffer.</param>
/// <param name="out">- the decoded mono audio frame.</param>
/// <returns>1 if a terminator was found, 0 if not.</returns>
/// <exception cref="java.io.StreamCorruptedException">
/// If there is an error detected in the
/// data stream.
/// </exception>
public virtual int decode(org.xiph.speex.Bits bits, float[] @out)
{
int i;
int sub;
int wideband;
int ret;
float[] low_pi_gain;
float[] low_exc;
float[] low_innov;
ret = lowdec.decode(bits, x0d);
if (ret != 0)
{
return ret;
}
bool dtx = lowdec.getDtx();
if (bits == null)
{
decodeLost(@out, dtx);
return 0;
}
wideband = bits.peek();
if (wideband != 0)
{
wideband = bits.unpack(1);
submodeID = bits.unpack(3);
}
else
{
submodeID = 0;
}
for (i = 0; i < frameSize; i++)
{
excBuf[i] = 0;
}
if (submodes[submodeID] == null)
{
if (dtx)
{
decodeLost(@out, true);
return 0;
}
for (i = 0; i < frameSize; i++)
{
excBuf[i] = VERY_SMALL;
}
first = 1;
org.xiph.speex.Filters.iir_mem2(excBuf, excIdx, interp_qlpc, high, 0, frameSize,
lpcSize, mem_sp);
filters.fir_mem_up(x0d, h0, y0, fullFrameSize, QMF_ORDER, g0_mem);
filters.fir_mem_up(high, h1, y1, fullFrameSize, QMF_ORDER, g1_mem);
for (i = 0; i < fullFrameSize; i++)
{
@out[i] = 2 * (y0[i] - y1[i]);
}
return 0;
}
low_pi_gain = lowdec.getPiGain();
low_exc = lowdec.getExc();
low_innov = lowdec.getInnov();
submodes[submodeID].lsqQuant.unquant(qlsp, lpcSize, bits);
if (first != 0)
{
for (i = 0; i < lpcSize; i++)
{
old_qlsp[i] = qlsp[i];
}
}
for (sub = 0; sub < nbSubframes; sub++)
{
float tmp;
float filter_ratio;
float el = 0.0f;
float rl = 0.0f;
float rh = 0.0f;
int subIdx = subframeSize * sub;
tmp = (1.0f + sub) / nbSubframes;
for (i = 0; i < lpcSize; i++)
{
interp_qlsp[i] = (1 - tmp) * old_qlsp[i] + tmp * qlsp[i];
}
org.xiph.speex.Lsp.enforce_margin(interp_qlsp, lpcSize, .05f);
for (i = 0; i < lpcSize; i++)
{
interp_qlsp[i] = (float)System.Math.Cos(interp_qlsp[i]);
}
m_lsp.lsp2lpc(interp_qlsp, interp_qlpc, lpcSize);
if (enhanced)
{
float k1;
float k2;
float k3;
k1 = submodes[submodeID].lpc_enh_k1;
k2 = submodes[submodeID].lpc_enh_k2;
k3 = k1 - k2;
org.xiph.speex.Filters.bw_lpc(k1, interp_qlpc, awk1, lpcSize);
org.xiph.speex.Filters.bw_lpc(k2, interp_qlpc, awk2, lpcSize);
org.xiph.speex.Filters.bw_lpc(k3, interp_qlpc, awk3, lpcSize);
}
tmp = 1;
pi_gain[sub] = 0;
for (i = 0; i <= lpcSize; i++)
{
rh += tmp * interp_qlpc[i];
tmp = -tmp;
pi_gain[sub] += interp_qlpc[i];
}
rl = low_pi_gain[sub];
rl = 1 / (System.Math.Abs(rl) + .01f);
rh = 1 / (System.Math.Abs(rh) + .01f);
filter_ratio = System.Math.Abs(.01f + rh) / (.01f + System.Math.Abs(rl));
for (i = subIdx; i < subIdx + subframeSize; i++)
{
excBuf[i] = 0;
}
if (submodes[submodeID].innovation == null)
{
float g;
int quant;
quant = bits.unpack(5);
g = (float)System.Math.Exp(((double)quant - 10) / 8.0);
g /= filter_ratio;
for (i = subIdx; i < subIdx + subframeSize; i++)
{
excBuf[i] = foldingGain * g * low_innov[i];
}
}
else
{
float gc;
float scale;
int qgc = bits.unpack(4);
for (i = subIdx; i < subIdx + subframeSize; i++)
{
el += low_exc[i] * low_exc[i];
}
gc = (float)System.Math.Exp((1 / 3.7f) * qgc - 2);
scale = gc * (float)System.Math.Sqrt(1 + el) / filter_ratio;
submodes[submodeID].innovation.unquant(excBuf, subIdx, subframeSize, bits);
for (i = subIdx; i < subIdx + subframeSize; i++)
{
excBuf[i] *= scale;
}
if (submodes[submodeID].double_codebook != 0)
{
for (i = 0; i < subframeSize; i++)
{
innov2[i] = 0;
}
submodes[submodeID].innovation.unquant(innov2, 0, subframeSize, bits);
for (i = 0; i < subframeSize; i++)
{
innov2[i] *= scale * (1 / 2.5f);
}
for (i = 0; i < subframeSize; i++)
{
excBuf[subIdx + i] += innov2[i];
}
}
}
for (i = subIdx; i < subIdx + subframeSize; i++)
{
high[i] = excBuf[i];
}
if (enhanced)
{
org.xiph.speex.Filters.filter_mem2(high, subIdx, awk2, awk1, subframeSize, lpcSize
, mem_sp, lpcSize);
org.xiph.speex.Filters.filter_mem2(high, subIdx, awk3, interp_qlpc, subframeSize,
lpcSize, mem_sp, 0);
}
else
{
for (i = 0; i < lpcSize; i++)
{
mem_sp[lpcSize + i] = 0;
}
org.xiph.speex.Filters.iir_mem2(high, subIdx, interp_qlpc, high, subIdx, subframeSize
, lpcSize, mem_sp);
}
}
filters.fir_mem_up(x0d, h0, y0, fullFrameSize, QMF_ORDER, g0_mem);
filters.fir_mem_up(high, h1, y1, fullFrameSize, QMF_ORDER, g1_mem);
for (i = 0; i < fullFrameSize; i++)
{
@out[i] = 2 * (y0[i] - y1[i]);
}
for (i = 0; i < lpcSize; i++)
{
old_qlsp[i] = qlsp[i];
}
first = 0;
return 0;
}
