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https://github.com/xenia-project/FFmpeg.git
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db1a642cd2
The idea is to use ffmath.h for internal implementations of math functions. Currently, it is used for variants of libm functions, but is by no means limited to such things. Note that this is not exported; use lavu/mathematics for such purposes. Reviewed-by: Ronald S. Bultje <rsbultje@gmail.com> Signed-off-by: Ganesh Ajjanagadde <gajjanag@gmail.com>
173 lines
5.5 KiB
C
173 lines
5.5 KiB
C
/*
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* RFC 3389 comfort noise generator
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* Copyright (c) 2012 Martin Storsjo
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg 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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* FFmpeg 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 FFmpeg; 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 <math.h>
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#include "libavutil/common.h"
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#include "libavutil/ffmath.h"
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#include "avcodec.h"
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#include "celp_filters.h"
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#include "internal.h"
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#include "libavutil/lfg.h"
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typedef struct CNGContext {
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float *refl_coef, *target_refl_coef;
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float *lpc_coef;
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int order;
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int energy, target_energy;
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int inited;
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float *filter_out;
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float *excitation;
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AVLFG lfg;
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} CNGContext;
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static av_cold int cng_decode_close(AVCodecContext *avctx)
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{
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CNGContext *p = avctx->priv_data;
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av_freep(&p->refl_coef);
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av_freep(&p->target_refl_coef);
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av_freep(&p->lpc_coef);
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av_freep(&p->filter_out);
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av_freep(&p->excitation);
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return 0;
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}
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static av_cold int cng_decode_init(AVCodecContext *avctx)
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{
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CNGContext *p = avctx->priv_data;
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avctx->sample_fmt = AV_SAMPLE_FMT_S16;
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avctx->channels = 1;
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avctx->sample_rate = 8000;
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p->order = 12;
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avctx->frame_size = 640;
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p->refl_coef = av_mallocz_array(p->order, sizeof(*p->refl_coef));
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p->target_refl_coef = av_mallocz_array(p->order, sizeof(*p->target_refl_coef));
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p->lpc_coef = av_mallocz_array(p->order, sizeof(*p->lpc_coef));
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p->filter_out = av_mallocz_array(avctx->frame_size + p->order,
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sizeof(*p->filter_out));
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p->excitation = av_mallocz_array(avctx->frame_size, sizeof(*p->excitation));
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if (!p->refl_coef || !p->target_refl_coef || !p->lpc_coef ||
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!p->filter_out || !p->excitation) {
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cng_decode_close(avctx);
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return AVERROR(ENOMEM);
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}
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av_lfg_init(&p->lfg, 0);
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return 0;
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}
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static void make_lpc_coefs(float *lpc, const float *refl, int order)
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{
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float buf[100];
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float *next, *cur;
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int m, i;
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next = buf;
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cur = lpc;
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for (m = 0; m < order; m++) {
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next[m] = refl[m];
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for (i = 0; i < m; i++)
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next[i] = cur[i] + refl[m] * cur[m - i - 1];
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FFSWAP(float*, next, cur);
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}
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if (cur != lpc)
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memcpy(lpc, cur, sizeof(*lpc) * order);
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}
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static void cng_decode_flush(AVCodecContext *avctx)
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{
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CNGContext *p = avctx->priv_data;
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p->inited = 0;
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}
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static int cng_decode_frame(AVCodecContext *avctx, void *data,
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int *got_frame_ptr, AVPacket *avpkt)
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{
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AVFrame *frame = data;
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CNGContext *p = avctx->priv_data;
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int buf_size = avpkt->size;
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int ret, i;
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int16_t *buf_out;
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float e = 1.0;
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float scaling;
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if (avpkt->size) {
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int dbov = -avpkt->data[0];
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p->target_energy = 1081109975 * ff_exp10(dbov / 10.0) * 0.75;
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memset(p->target_refl_coef, 0, p->order * sizeof(*p->target_refl_coef));
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for (i = 0; i < FFMIN(avpkt->size - 1, p->order); i++) {
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p->target_refl_coef[i] = (avpkt->data[1 + i] - 127) / 128.0;
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}
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}
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if (p->inited) {
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p->energy = p->energy / 2 + p->target_energy / 2;
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for (i = 0; i < p->order; i++)
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p->refl_coef[i] = 0.6 *p->refl_coef[i] + 0.4 * p->target_refl_coef[i];
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} else {
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p->energy = p->target_energy;
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memcpy(p->refl_coef, p->target_refl_coef, p->order * sizeof(*p->refl_coef));
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p->inited = 1;
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}
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make_lpc_coefs(p->lpc_coef, p->refl_coef, p->order);
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for (i = 0; i < p->order; i++)
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e *= 1.0 - p->refl_coef[i]*p->refl_coef[i];
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scaling = sqrt(e * p->energy / 1081109975);
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for (i = 0; i < avctx->frame_size; i++) {
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int r = (av_lfg_get(&p->lfg) & 0xffff) - 0x8000;
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p->excitation[i] = scaling * r;
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}
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ff_celp_lp_synthesis_filterf(p->filter_out + p->order, p->lpc_coef,
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p->excitation, avctx->frame_size, p->order);
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frame->nb_samples = avctx->frame_size;
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if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
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return ret;
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buf_out = (int16_t *)frame->data[0];
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for (i = 0; i < avctx->frame_size; i++)
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buf_out[i] = p->filter_out[i + p->order];
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memcpy(p->filter_out, p->filter_out + avctx->frame_size,
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p->order * sizeof(*p->filter_out));
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*got_frame_ptr = 1;
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return buf_size;
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}
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AVCodec ff_comfortnoise_decoder = {
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.name = "comfortnoise",
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.long_name = NULL_IF_CONFIG_SMALL("RFC 3389 comfort noise generator"),
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.type = AVMEDIA_TYPE_AUDIO,
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.id = AV_CODEC_ID_COMFORT_NOISE,
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.priv_data_size = sizeof(CNGContext),
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.init = cng_decode_init,
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.decode = cng_decode_frame,
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.flush = cng_decode_flush,
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.close = cng_decode_close,
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.sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
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AV_SAMPLE_FMT_NONE },
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.capabilities = AV_CODEC_CAP_DELAY | AV_CODEC_CAP_DR1,
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};
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