mirror of
https://git.videolan.org/git/ffmpeg.git
synced 2024-09-10 17:41:09 +02:00
![Colin McQuillan](/assets/img/avatar_default.png)
qcelp_lsp exported a single function, ff_acelp_lspd2lpc, which was not specific to qcelp. It can be kept with its fixed-point version ff_acelp_lsp2lpc in lpc.c. Patch by Colin McQuillan ( m.niloc googlemail com ) Originally committed as revision 19571 to svn://svn.ffmpeg.org/ffmpeg/trunk
167 lines
4.7 KiB
C
167 lines
4.7 KiB
C
/*
|
|
* LSP routines for ACELP-based codecs
|
|
*
|
|
* Copyright (c) 2007 Reynaldo H. Verdejo Pinochet (QCELP decoder)
|
|
* Copyright (c) 2008 Vladimir Voroshilov
|
|
*
|
|
* This file is part of FFmpeg.
|
|
*
|
|
* FFmpeg is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* FFmpeg is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with FFmpeg; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
#include <inttypes.h>
|
|
|
|
#include "avcodec.h"
|
|
#define FRAC_BITS 14
|
|
#include "mathops.h"
|
|
#include "lsp.h"
|
|
#include "celp_math.h"
|
|
|
|
void ff_acelp_reorder_lsf(int16_t* lsfq, int lsfq_min_distance, int lsfq_min, int lsfq_max, int lp_order)
|
|
{
|
|
int i, j;
|
|
|
|
/* sort lsfq in ascending order. float bubble agorithm,
|
|
O(n) if data already sorted, O(n^2) - otherwise */
|
|
for(i=0; i<lp_order-1; i++)
|
|
for(j=i; j>=0 && lsfq[j] > lsfq[j+1]; j--)
|
|
FFSWAP(int16_t, lsfq[j], lsfq[j+1]);
|
|
|
|
for(i=0; i<lp_order; i++)
|
|
{
|
|
lsfq[i] = FFMAX(lsfq[i], lsfq_min);
|
|
lsfq_min = lsfq[i] + lsfq_min_distance;
|
|
}
|
|
lsfq[lp_order-1] = FFMIN(lsfq[lp_order-1], lsfq_max);//Is warning required ?
|
|
}
|
|
|
|
void ff_acelp_lsf2lsp(int16_t *lsp, const int16_t *lsf, int lp_order)
|
|
{
|
|
int i;
|
|
|
|
/* Convert LSF to LSP, lsp=cos(lsf) */
|
|
for(i=0; i<lp_order; i++)
|
|
// 20861 = 2.0 / PI in (0.15)
|
|
lsp[i] = ff_cos(lsf[i] * 20861 >> 15); // divide by PI and (0,13) -> (0,14)
|
|
}
|
|
|
|
/**
|
|
* \brief decodes polynomial coefficients from LSP
|
|
* \param f [out] decoded polynomial coefficients (-0x20000000 <= (3.22) <= 0x1fffffff)
|
|
* \param lsp LSP coefficients (-0x8000 <= (0.15) <= 0x7fff)
|
|
*/
|
|
static void lsp2poly(int* f, const int16_t* lsp, int lp_half_order)
|
|
{
|
|
int i, j;
|
|
|
|
f[0] = 0x400000; // 1.0 in (3.22)
|
|
f[1] = -lsp[0] << 8; // *2 and (0.15) -> (3.22)
|
|
|
|
for(i=2; i<=lp_half_order; i++)
|
|
{
|
|
f[i] = f[i-2];
|
|
for(j=i; j>1; j--)
|
|
f[j] -= MULL(f[j-1], lsp[2*i-2], FRAC_BITS) - f[j-2];
|
|
|
|
f[1] -= lsp[2*i-2] << 8;
|
|
}
|
|
}
|
|
|
|
void ff_acelp_lsp2lpc(int16_t* lp, const int16_t* lsp, int lp_half_order)
|
|
{
|
|
int i;
|
|
int f1[lp_half_order+1]; // (3.22)
|
|
int f2[lp_half_order+1]; // (3.22)
|
|
|
|
lsp2poly(f1, lsp , lp_half_order);
|
|
lsp2poly(f2, lsp+1, lp_half_order);
|
|
|
|
/* 3.2.6 of G.729, Equations 25 and 26*/
|
|
lp[0] = 4096;
|
|
for(i=1; i<lp_half_order+1; i++)
|
|
{
|
|
int ff1 = f1[i] + f1[i-1]; // (3.22)
|
|
int ff2 = f2[i] - f2[i-1]; // (3.22)
|
|
|
|
ff1 += 1 << 10; // for rounding
|
|
lp[i] = (ff1 + ff2) >> 11; // divide by 2 and (3.22) -> (3.12)
|
|
lp[(lp_half_order << 1) + 1 - i] = (ff1 - ff2) >> 11; // divide by 2 and (3.22) -> (3.12)
|
|
}
|
|
}
|
|
|
|
void ff_acelp_lp_decode(int16_t* lp_1st, int16_t* lp_2nd, const int16_t* lsp_2nd, const int16_t* lsp_prev, int lp_order)
|
|
{
|
|
int16_t lsp_1st[lp_order]; // (0.15)
|
|
int i;
|
|
|
|
/* LSP values for first subframe (3.2.5 of G.729, Equation 24)*/
|
|
for(i=0; i<lp_order; i++)
|
|
#ifdef G729_BITEXACT
|
|
lsp_1st[i] = (lsp_2nd[i] >> 1) + (lsp_prev[i] >> 1);
|
|
#else
|
|
lsp_1st[i] = (lsp_2nd[i] + lsp_prev[i]) >> 1;
|
|
#endif
|
|
|
|
ff_acelp_lsp2lpc(lp_1st, lsp_1st, lp_order >> 1);
|
|
|
|
/* LSP values for second subframe (3.2.5 of G.729)*/
|
|
ff_acelp_lsp2lpc(lp_2nd, lsp_2nd, lp_order >> 1);
|
|
}
|
|
|
|
/**
|
|
* Computes the Pa / (1 + z(-1)) or Qa / (1 - z(-1)) coefficients
|
|
* needed for LSP to LPC conversion.
|
|
* We only need to calculate the 6 first elements of the polynomial.
|
|
*
|
|
* @param lsp line spectral pairs in cosine domain
|
|
* @param f [out] polynomial input/output as a vector
|
|
*
|
|
* TIA/EIA/IS-733 2.4.3.3.5-1/2
|
|
*/
|
|
static void lsp2polyf(const double *lsp, double *f, int lp_half_order)
|
|
{
|
|
int i, j;
|
|
|
|
f[0] = 1.0;
|
|
f[1] = -2 * lsp[0];
|
|
lsp -= 2;
|
|
for(i=2; i<=lp_half_order; i++)
|
|
{
|
|
double val = -2 * lsp[2*i];
|
|
f[i] = val * f[i-1] + 2*f[i-2];
|
|
for(j=i-1; j>1; j--)
|
|
f[j] += f[j-1] * val + f[j-2];
|
|
f[1] += val;
|
|
}
|
|
}
|
|
|
|
void ff_acelp_lspd2lpc(const double *lsp, float *lpc)
|
|
{
|
|
double pa[6], qa[6];
|
|
int i;
|
|
|
|
lsp2polyf(lsp, pa, 5);
|
|
lsp2polyf(lsp + 1, qa, 5);
|
|
|
|
for (i=4; i>=0; i--)
|
|
{
|
|
double paf = pa[i+1] + pa[i];
|
|
double qaf = qa[i+1] - qa[i];
|
|
|
|
lpc[i ] = 0.5*(paf+qaf);
|
|
lpc[9-i] = 0.5*(paf-qaf);
|
|
}
|
|
}
|