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https://github.com/pineappleEA/pineapple-src.git
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180 lines
5.7 KiB
C
Executable File
180 lines
5.7 KiB
C
Executable File
/*
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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 "libavutil/intreadwrite.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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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 (avctx->internal->skip_samples > 10 * avctx->frame_size) {
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avctx->internal->skip_samples = 0;
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return AVERROR_INVALIDDATA;
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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] = av_clip_int16(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_DR1,
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.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE |
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FF_CODEC_CAP_INIT_CLEANUP,
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};
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