0,0 → 1,116 |
/* |
* 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); |
} |
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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_array(avctx->frame_size, sizeof(*p->samples32)); |
p->ref_coef = av_malloc_array(p->order, sizeof(*p->ref_coef)); |
if (!p->samples32 || !p->ref_coef) { |
cng_encode_close(avctx); |
return AVERROR(ENOMEM); |
} |
|
return 0; |
} |
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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_packet2(avctx, avpkt, 1 + p->order, 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_uintp2(-floor(dbov), 7); |
} 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; |
av_assert1(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 }, |
}; |