unsafe void encode_residual_lpc_sub(FlacFrame frame, float* lpcs, int iWindow, int order, int ch)
{
// select LPC precision based on block size
uint lpc_precision;
if (frame.blocksize <= 192) lpc_precision = 7U;
else if (frame.blocksize <= 384) lpc_precision = 8U;
else if (frame.blocksize <= 576) lpc_precision = 9U;
else if (frame.blocksize <= 1152) lpc_precision = 10U;
else if (frame.blocksize <= 2304) lpc_precision = 11U;
else if (frame.blocksize <= 4608) lpc_precision = 12U;
else if (frame.blocksize <= 8192) lpc_precision = 13U;
else if (frame.blocksize <= 16384) lpc_precision = 14U;
else lpc_precision = 15;
for (int i_precision = eparams.lpc_min_precision_search; i_precision <= eparams.lpc_max_precision_search && lpc_precision + i_precision < 16; i_precision++)
// check if we already calculated with this order, window and precision
if ((frame.subframes[ch].lpc_ctx[iWindow].done_lpcs[i_precision] & (1U << (order - 1))) == 0)
{
frame.subframes[ch].lpc_ctx[iWindow].done_lpcs[i_precision] |= (1U << (order - 1));
uint cbits = lpc_precision + (uint)i_precision;
frame.current.type = SubframeType.LPC;
frame.current.order = order;
frame.current.window = iWindow;
fixed (int* coefs = frame.current.coefs)
{
lpc.quantize_lpc_coefs(lpcs + (frame.current.order - 1) * lpc.MAX_LPC_ORDER,
frame.current.order, cbits, coefs, out frame.current.shift, 15, 0);
if (frame.current.shift < 0 || frame.current.shift > 15)
throw new Exception("negative shift");
ulong csum = 0;
for (int i = frame.current.order; i > 0; i--)
csum += (ulong)Math.Abs(coefs[i - 1]);
if ((csum << frame.subframes[ch].obits) >= 1UL << 32)
lpc.encode_residual_long(frame.current.residual, frame.subframes[ch].samples, frame.blocksize, frame.current.order, coefs, frame.current.shift);
else
lpc.encode_residual(frame.current.residual, frame.subframes[ch].samples, frame.blocksize, frame.current.order, coefs, frame.current.shift);
}
int pmax = get_max_p_order(eparams.max_partition_order, frame.blocksize, frame.current.order);
int pmin = Math.Min(eparams.min_partition_order, pmax);
uint best_size = calc_rice_params(frame.current.rc, pmin, pmax, frame.current.residual, (uint)frame.blocksize, (uint)frame.current.order, PCM.BitsPerSample);
// not working
//for (int o = 1; o <= frame.current.order; o++)
//{
// if (frame.current.coefs[o - 1] > -(1 << frame.current.shift))
// {
// for (int i = o; i < frame.blocksize; i++)
// frame.current.residual[i] += frame.subframes[ch].samples[i - o] >> frame.current.shift;
// frame.current.coefs[o - 1]--;
// uint new_size = calc_rice_params(ref frame.current.rc, pmin, pmax, frame.current.residual, (uint)frame.blocksize, (uint)frame.current.order);
// if (new_size > best_size)
// {
// for (int i = o; i < frame.blocksize; i++)
// frame.current.residual[i] -= frame.subframes[ch].samples[i - o] >> frame.current.shift;
// frame.current.coefs[o - 1]++;
// }
// }
//}
frame.current.size = (uint)(frame.current.order * frame.subframes[ch].obits + 4 + 5 + frame.current.order * (int)cbits + 6 + (int)best_size);
frame.ChooseBestSubframe(ch);
}
}