forked from KolibriOS/kolibrios
117 lines
3.5 KiB
C
117 lines
3.5 KiB
C
/*
|
|
* RFC 3389 comfort noise generator
|
|
* Copyright (c) 2012 Martin Storsjo
|
|
*
|
|
* 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 <math.h>
|
|
|
|
#include "libavutil/common.h"
|
|
#include "avcodec.h"
|
|
#include "internal.h"
|
|
#include "lpc.h"
|
|
|
|
typedef struct CNGContext {
|
|
LPCContext lpc;
|
|
int order;
|
|
int32_t *samples32;
|
|
double *ref_coef;
|
|
} CNGContext;
|
|
|
|
static av_cold int cng_encode_close(AVCodecContext *avctx)
|
|
{
|
|
CNGContext *p = avctx->priv_data;
|
|
ff_lpc_end(&p->lpc);
|
|
av_free(p->samples32);
|
|
av_free(p->ref_coef);
|
|
return 0;
|
|
}
|
|
|
|
static av_cold int cng_encode_init(AVCodecContext *avctx)
|
|
{
|
|
CNGContext *p = avctx->priv_data;
|
|
int ret;
|
|
|
|
if (avctx->channels != 1) {
|
|
av_log(avctx, AV_LOG_ERROR, "Only mono supported\n");
|
|
return AVERROR(EINVAL);
|
|
}
|
|
|
|
avctx->frame_size = 640;
|
|
p->order = 10;
|
|
if ((ret = ff_lpc_init(&p->lpc, avctx->frame_size, p->order, FF_LPC_TYPE_LEVINSON)) < 0)
|
|
return ret;
|
|
p->samples32 = av_malloc(avctx->frame_size * sizeof(*p->samples32));
|
|
p->ref_coef = av_malloc(p->order * sizeof(*p->ref_coef));
|
|
if (!p->samples32 || !p->ref_coef) {
|
|
cng_encode_close(avctx);
|
|
return AVERROR(ENOMEM);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int cng_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
|
|
const AVFrame *frame, int *got_packet_ptr)
|
|
{
|
|
CNGContext *p = avctx->priv_data;
|
|
int ret, i;
|
|
double energy = 0;
|
|
int qdbov;
|
|
int16_t *samples = (int16_t*) frame->data[0];
|
|
|
|
if ((ret = ff_alloc_packet(avpkt, 1 + p->order))) {
|
|
av_log(avctx, AV_LOG_ERROR, "Error getting output packet\n");
|
|
return ret;
|
|
}
|
|
|
|
for (i = 0; i < frame->nb_samples; i++) {
|
|
p->samples32[i] = samples[i];
|
|
energy += samples[i] * samples[i];
|
|
}
|
|
energy /= frame->nb_samples;
|
|
if (energy > 0) {
|
|
double dbov = 10 * log10(energy / 1081109975);
|
|
qdbov = av_clip(-floor(dbov), 0, 127);
|
|
} else {
|
|
qdbov = 127;
|
|
}
|
|
ret = ff_lpc_calc_ref_coefs(&p->lpc, p->samples32, p->order, p->ref_coef);
|
|
avpkt->data[0] = qdbov;
|
|
for (i = 0; i < p->order; i++)
|
|
avpkt->data[1 + i] = p->ref_coef[i] * 127 + 127;
|
|
|
|
*got_packet_ptr = 1;
|
|
avpkt->size = 1 + p->order;
|
|
|
|
return 0;
|
|
}
|
|
|
|
AVCodec ff_comfortnoise_encoder = {
|
|
.name = "comfortnoise",
|
|
.long_name = NULL_IF_CONFIG_SMALL("RFC 3389 comfort noise generator"),
|
|
.type = AVMEDIA_TYPE_AUDIO,
|
|
.id = AV_CODEC_ID_COMFORT_NOISE,
|
|
.priv_data_size = sizeof(CNGContext),
|
|
.init = cng_encode_init,
|
|
.encode2 = cng_encode_frame,
|
|
.close = cng_encode_close,
|
|
.sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
|
|
AV_SAMPLE_FMT_NONE },
|
|
};
|