185 lines
8.7 KiB
C#
185 lines
8.7 KiB
C#
/* Copyright (c) 2006-2011 Skype Limited. All Rights Reserved
|
|
Ported to C# by Logan Stromberg
|
|
|
|
Redistribution and use in source and binary forms, with or without
|
|
modification, are permitted provided that the following conditions
|
|
are met:
|
|
|
|
- Redistributions of source code must retain the above copyright
|
|
notice, this list of conditions and the following disclaimer.
|
|
|
|
- Redistributions in binary form must reproduce the above copyright
|
|
notice, this list of conditions and the following disclaimer in the
|
|
documentation and/or other materials provided with the distribution.
|
|
|
|
- Neither the name of Internet Society, IETF or IETF Trust, nor the
|
|
names of specific contributors, may be used to endorse or promote
|
|
products derived from this software without specific prior written
|
|
permission.
|
|
|
|
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
|
|
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
|
|
OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
|
|
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
|
|
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
|
|
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
|
|
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
|
|
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
|
|
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
|
|
namespace Concentus.Silk
|
|
{
|
|
using Concentus.Common;
|
|
using Concentus.Common.CPlusPlus;
|
|
using Concentus.Silk.Enums;
|
|
using Concentus.Silk.Structs;
|
|
using System.Diagnostics;
|
|
|
|
internal static class FindLPC
|
|
{
|
|
/* Finds LPC vector from correlations, and converts to NLSF */
|
|
internal static void silk_find_LPC(
|
|
SilkChannelEncoder psEncC, /* I/O Encoder state */
|
|
short[] NLSF_Q15, /* O NLSFs */
|
|
short[] x, /* I Input signal */
|
|
int minInvGain_Q30 /* I Inverse of max prediction gain */
|
|
)
|
|
{
|
|
int k, subfr_length;
|
|
int[] a_Q16 = new int[SilkConstants.MAX_LPC_ORDER];
|
|
int isInterpLower, shift;
|
|
int res_nrg0, res_nrg1;
|
|
int rshift0, rshift1;
|
|
BoxedValueInt scratch_box1 = new BoxedValueInt();
|
|
BoxedValueInt scratch_box2 = new BoxedValueInt();
|
|
|
|
/* Used only for LSF interpolation */
|
|
int[] a_tmp_Q16 = new int[SilkConstants.MAX_LPC_ORDER];
|
|
int res_nrg_interp, res_nrg, res_tmp_nrg;
|
|
int res_nrg_interp_Q, res_nrg_Q, res_tmp_nrg_Q;
|
|
short[] a_tmp_Q12 = new short[SilkConstants.MAX_LPC_ORDER];
|
|
short[] NLSF0_Q15 = new short[SilkConstants.MAX_LPC_ORDER];
|
|
|
|
subfr_length = psEncC.subfr_length + psEncC.predictLPCOrder;
|
|
|
|
/* Default: no interpolation */
|
|
psEncC.indices.NLSFInterpCoef_Q2 = 4;
|
|
|
|
/* Burg AR analysis for the full frame */
|
|
BurgModified.silk_burg_modified(scratch_box1, scratch_box2, a_Q16, x, 0, minInvGain_Q30, subfr_length, psEncC.nb_subfr, psEncC.predictLPCOrder);
|
|
res_nrg = scratch_box1.Val;
|
|
res_nrg_Q = scratch_box2.Val;
|
|
|
|
if (psEncC.useInterpolatedNLSFs != 0 && psEncC.first_frame_after_reset == 0 && psEncC.nb_subfr == SilkConstants.MAX_NB_SUBFR)
|
|
{
|
|
short[] LPC_res;
|
|
|
|
/* Optimal solution for last 10 ms */
|
|
BurgModified.silk_burg_modified(scratch_box1, scratch_box2, a_tmp_Q16, x, (2 * subfr_length), minInvGain_Q30, subfr_length, 2, psEncC.predictLPCOrder);
|
|
res_tmp_nrg = scratch_box1.Val;
|
|
res_tmp_nrg_Q = scratch_box2.Val;
|
|
|
|
/* subtract residual energy here, as that's easier than adding it to the */
|
|
/* residual energy of the first 10 ms in each iteration of the search below */
|
|
shift = res_tmp_nrg_Q - res_nrg_Q;
|
|
if (shift >= 0)
|
|
{
|
|
if (shift < 32)
|
|
{
|
|
res_nrg = res_nrg - Inlines.silk_RSHIFT(res_tmp_nrg, shift);
|
|
}
|
|
}
|
|
else {
|
|
Inlines.OpusAssert(shift > -32);
|
|
res_nrg = Inlines.silk_RSHIFT(res_nrg, -shift) - res_tmp_nrg;
|
|
res_nrg_Q = res_tmp_nrg_Q;
|
|
}
|
|
|
|
/* Convert to NLSFs */
|
|
NLSF.silk_A2NLSF(NLSF_Q15, a_tmp_Q16, psEncC.predictLPCOrder);
|
|
|
|
LPC_res = new short[2 * subfr_length];
|
|
|
|
/* Search over interpolation indices to find the one with lowest residual energy */
|
|
for (k = 3; k >= 0; k--)
|
|
{
|
|
/* Interpolate NLSFs for first half */
|
|
Inlines.silk_interpolate(NLSF0_Q15, psEncC.prev_NLSFq_Q15, NLSF_Q15, k, psEncC.predictLPCOrder);
|
|
|
|
/* Convert to LPC for residual energy evaluation */
|
|
NLSF.silk_NLSF2A(a_tmp_Q12, NLSF0_Q15, psEncC.predictLPCOrder);
|
|
|
|
/* Calculate residual energy with NLSF interpolation */
|
|
Filters.silk_LPC_analysis_filter(LPC_res, 0, x, 0, a_tmp_Q12, 0, 2 * subfr_length, psEncC.predictLPCOrder);
|
|
|
|
SumSqrShift.silk_sum_sqr_shift(out res_nrg0, out rshift0, LPC_res, psEncC.predictLPCOrder, subfr_length - psEncC.predictLPCOrder);
|
|
|
|
SumSqrShift.silk_sum_sqr_shift(out res_nrg1, out rshift1, LPC_res, psEncC.predictLPCOrder + subfr_length, subfr_length - psEncC.predictLPCOrder);
|
|
|
|
/* Add subframe energies from first half frame */
|
|
shift = rshift0 - rshift1;
|
|
if (shift >= 0)
|
|
{
|
|
res_nrg1 = Inlines.silk_RSHIFT(res_nrg1, shift);
|
|
res_nrg_interp_Q = -rshift0;
|
|
}
|
|
else {
|
|
res_nrg0 = Inlines.silk_RSHIFT(res_nrg0, -shift);
|
|
res_nrg_interp_Q = -rshift1;
|
|
}
|
|
res_nrg_interp = Inlines.silk_ADD32(res_nrg0, res_nrg1);
|
|
|
|
/* Compare with first half energy without NLSF interpolation, or best interpolated value so far */
|
|
shift = res_nrg_interp_Q - res_nrg_Q;
|
|
if (shift >= 0)
|
|
{
|
|
if (Inlines.silk_RSHIFT(res_nrg_interp, shift) < res_nrg)
|
|
{
|
|
isInterpLower = (true ? 1 : 0);
|
|
}
|
|
else {
|
|
isInterpLower = (false ? 1 : 0);
|
|
}
|
|
}
|
|
else {
|
|
if (-shift < 32)
|
|
{
|
|
if (res_nrg_interp < Inlines.silk_RSHIFT(res_nrg, -shift))
|
|
{
|
|
isInterpLower = (true ? 1 : 0);
|
|
}
|
|
else {
|
|
isInterpLower = (false ? 1 : 0);
|
|
}
|
|
}
|
|
else {
|
|
isInterpLower = (false ? 1 : 0);
|
|
}
|
|
}
|
|
|
|
/* Determine whether current interpolated NLSFs are best so far */
|
|
if (isInterpLower == (true ? 1 : 0))
|
|
{
|
|
/* Interpolation has lower residual energy */
|
|
res_nrg = res_nrg_interp;
|
|
res_nrg_Q = res_nrg_interp_Q;
|
|
psEncC.indices.NLSFInterpCoef_Q2 = (sbyte)k;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (psEncC.indices.NLSFInterpCoef_Q2 == 4)
|
|
{
|
|
/* NLSF interpolation is currently inactive, calculate NLSFs from full frame AR coefficients */
|
|
NLSF.silk_A2NLSF(NLSF_Q15, a_Q16, psEncC.predictLPCOrder);
|
|
}
|
|
|
|
Inlines.OpusAssert(psEncC.indices.NLSFInterpCoef_Q2 == 4 || (psEncC.useInterpolatedNLSFs != 0 && psEncC.first_frame_after_reset == 0 && psEncC.nb_subfr == SilkConstants.MAX_NB_SUBFR));
|
|
|
|
}
|
|
}
|
|
}
|