mirror of
https://github.com/FFmpeg/FFmpeg.git
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f023d57d35
Additional improvements by Michael Niedermayer <michaelni@gmx.at>. Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>
263 lines
8.0 KiB
C
263 lines
8.0 KiB
C
/*
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* G.723.1 compatible decoder
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* Copyright (c) 2006 Benjamin Larsson
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* Copyright (c) 2010 Mohamed Naufal Basheer
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <stdint.h>
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#include "libavutil/common.h"
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#include "acelp_vectors.h"
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#include "avcodec.h"
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#include "celp_math.h"
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#include "g723_1.h"
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int ff_g723_1_scale_vector(int16_t *dst, const int16_t *vector, int length)
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{
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int bits, max = 0;
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int i;
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for (i = 0; i < length; i++)
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max |= FFABS(vector[i]);
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max = FFMIN(max, 0x7FFF);
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bits = ff_g723_1_normalize_bits(max, 15);
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for (i = 0; i < length; i++)
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dst[i] = vector[i] << bits >> 3;
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return bits - 3;
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}
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int ff_g723_1_normalize_bits(int num, int width)
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{
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return width - av_log2(num) - 1;
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}
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int ff_g723_1_dot_product(const int16_t *a, const int16_t *b, int length)
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{
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int sum = ff_dot_product(a, b, length);
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return av_sat_add32(sum, sum);
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}
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void ff_g723_1_get_residual(int16_t *residual, int16_t *prev_excitation,
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int lag)
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{
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int offset = PITCH_MAX - PITCH_ORDER / 2 - lag;
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int i;
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residual[0] = prev_excitation[offset];
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residual[1] = prev_excitation[offset + 1];
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offset += 2;
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for (i = 2; i < SUBFRAME_LEN + PITCH_ORDER - 1; i++)
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residual[i] = prev_excitation[offset + (i - 2) % lag];
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}
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void ff_g723_1_gen_dirac_train(int16_t *buf, int pitch_lag)
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{
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int16_t vector[SUBFRAME_LEN];
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int i, j;
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memcpy(vector, buf, SUBFRAME_LEN * sizeof(*vector));
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for (i = pitch_lag; i < SUBFRAME_LEN; i += pitch_lag) {
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for (j = 0; j < SUBFRAME_LEN - i; j++)
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buf[i + j] += vector[j];
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}
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}
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void ff_g723_1_gen_acb_excitation(int16_t *vector, int16_t *prev_excitation,
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int pitch_lag, G723_1_Subframe *subfrm,
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enum Rate cur_rate)
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{
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int16_t residual[SUBFRAME_LEN + PITCH_ORDER - 1];
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const int16_t *cb_ptr;
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int lag = pitch_lag + subfrm->ad_cb_lag - 1;
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int i;
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int sum;
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ff_g723_1_get_residual(residual, prev_excitation, lag);
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/* Select quantization table */
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if (cur_rate == RATE_6300 && pitch_lag < SUBFRAME_LEN - 2)
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cb_ptr = adaptive_cb_gain85;
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else
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cb_ptr = adaptive_cb_gain170;
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/* Calculate adaptive vector */
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cb_ptr += subfrm->ad_cb_gain * 20;
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for (i = 0; i < SUBFRAME_LEN; i++) {
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sum = ff_g723_1_dot_product(residual + i, cb_ptr, PITCH_ORDER);
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vector[i] = av_sat_dadd32(1 << 15, sum) >> 16;
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}
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}
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/**
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* Convert LSP frequencies to LPC coefficients.
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*
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* @param lpc buffer for LPC coefficients
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*/
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static void lsp2lpc(int16_t *lpc)
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{
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int f1[LPC_ORDER / 2 + 1];
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int f2[LPC_ORDER / 2 + 1];
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int i, j;
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/* Calculate negative cosine */
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for (j = 0; j < LPC_ORDER; j++) {
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int index = (lpc[j] >> 7) & 0x1FF;
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int offset = lpc[j] & 0x7f;
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int temp1 = cos_tab[index] << 16;
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int temp2 = (cos_tab[index + 1] - cos_tab[index]) *
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((offset << 8) + 0x80) << 1;
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lpc[j] = -(av_sat_dadd32(1 << 15, temp1 + temp2) >> 16);
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}
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/*
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* Compute sum and difference polynomial coefficients
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* (bitexact alternative to lsp2poly() in lsp.c)
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*/
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/* Initialize with values in Q28 */
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f1[0] = 1 << 28;
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f1[1] = (lpc[0] << 14) + (lpc[2] << 14);
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f1[2] = lpc[0] * lpc[2] + (2 << 28);
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f2[0] = 1 << 28;
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f2[1] = (lpc[1] << 14) + (lpc[3] << 14);
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f2[2] = lpc[1] * lpc[3] + (2 << 28);
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/*
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* Calculate and scale the coefficients by 1/2 in
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* each iteration for a final scaling factor of Q25
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*/
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for (i = 2; i < LPC_ORDER / 2; i++) {
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f1[i + 1] = f1[i - 1] + MULL2(f1[i], lpc[2 * i]);
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f2[i + 1] = f2[i - 1] + MULL2(f2[i], lpc[2 * i + 1]);
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for (j = i; j >= 2; j--) {
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f1[j] = MULL2(f1[j - 1], lpc[2 * i]) +
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(f1[j] >> 1) + (f1[j - 2] >> 1);
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f2[j] = MULL2(f2[j - 1], lpc[2 * i + 1]) +
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(f2[j] >> 1) + (f2[j - 2] >> 1);
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}
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f1[0] >>= 1;
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f2[0] >>= 1;
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f1[1] = ((lpc[2 * i] << 16 >> i) + f1[1]) >> 1;
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f2[1] = ((lpc[2 * i + 1] << 16 >> i) + f2[1]) >> 1;
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}
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/* Convert polynomial coefficients to LPC coefficients */
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for (i = 0; i < LPC_ORDER / 2; i++) {
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int64_t ff1 = f1[i + 1] + f1[i];
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int64_t ff2 = f2[i + 1] - f2[i];
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lpc[i] = av_clipl_int32(((ff1 + ff2) << 3) +
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(1 << 15)) >> 16;
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lpc[LPC_ORDER - i - 1] = av_clipl_int32(((ff1 - ff2) << 3) +
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(1 << 15)) >> 16;
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}
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}
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void ff_g723_1_lsp_interpolate(int16_t *lpc, int16_t *cur_lsp,
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int16_t *prev_lsp)
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{
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int i;
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int16_t *lpc_ptr = lpc;
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/* cur_lsp * 0.25 + prev_lsp * 0.75 */
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ff_acelp_weighted_vector_sum(lpc, cur_lsp, prev_lsp,
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4096, 12288, 1 << 13, 14, LPC_ORDER);
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ff_acelp_weighted_vector_sum(lpc + LPC_ORDER, cur_lsp, prev_lsp,
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8192, 8192, 1 << 13, 14, LPC_ORDER);
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ff_acelp_weighted_vector_sum(lpc + 2 * LPC_ORDER, cur_lsp, prev_lsp,
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12288, 4096, 1 << 13, 14, LPC_ORDER);
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memcpy(lpc + 3 * LPC_ORDER, cur_lsp, LPC_ORDER * sizeof(*lpc));
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for (i = 0; i < SUBFRAMES; i++) {
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lsp2lpc(lpc_ptr);
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lpc_ptr += LPC_ORDER;
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}
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}
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void ff_g723_1_inverse_quant(int16_t *cur_lsp, int16_t *prev_lsp,
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uint8_t *lsp_index, int bad_frame)
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{
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int min_dist, pred;
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int i, j, temp, stable;
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/* Check for frame erasure */
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if (!bad_frame) {
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min_dist = 0x100;
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pred = 12288;
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} else {
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min_dist = 0x200;
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pred = 23552;
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lsp_index[0] = lsp_index[1] = lsp_index[2] = 0;
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}
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/* Get the VQ table entry corresponding to the transmitted index */
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cur_lsp[0] = lsp_band0[lsp_index[0]][0];
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cur_lsp[1] = lsp_band0[lsp_index[0]][1];
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cur_lsp[2] = lsp_band0[lsp_index[0]][2];
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cur_lsp[3] = lsp_band1[lsp_index[1]][0];
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cur_lsp[4] = lsp_band1[lsp_index[1]][1];
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cur_lsp[5] = lsp_band1[lsp_index[1]][2];
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cur_lsp[6] = lsp_band2[lsp_index[2]][0];
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cur_lsp[7] = lsp_band2[lsp_index[2]][1];
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cur_lsp[8] = lsp_band2[lsp_index[2]][2];
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cur_lsp[9] = lsp_band2[lsp_index[2]][3];
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/* Add predicted vector & DC component to the previously quantized vector */
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for (i = 0; i < LPC_ORDER; i++) {
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temp = ((prev_lsp[i] - dc_lsp[i]) * pred + (1 << 14)) >> 15;
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cur_lsp[i] += dc_lsp[i] + temp;
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}
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for (i = 0; i < LPC_ORDER; i++) {
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cur_lsp[0] = FFMAX(cur_lsp[0], 0x180);
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cur_lsp[LPC_ORDER - 1] = FFMIN(cur_lsp[LPC_ORDER - 1], 0x7e00);
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/* Stability check */
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for (j = 1; j < LPC_ORDER; j++) {
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temp = min_dist + cur_lsp[j - 1] - cur_lsp[j];
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if (temp > 0) {
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temp >>= 1;
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cur_lsp[j - 1] -= temp;
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cur_lsp[j] += temp;
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}
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}
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stable = 1;
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for (j = 1; j < LPC_ORDER; j++) {
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temp = cur_lsp[j - 1] + min_dist - cur_lsp[j] - 4;
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if (temp > 0) {
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stable = 0;
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break;
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}
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}
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if (stable)
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break;
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}
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if (!stable)
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memcpy(cur_lsp, prev_lsp, LPC_ORDER * sizeof(*cur_lsp));
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}
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