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FFmpeg/libavcodec/g729_parser.c

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/*
* Copyright (c) 2015 Ganesh Ajjanagadde
*
* 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
*/
/**
* @file
* G.729 audio parser
*
* Splits packets into individual blocks.
*/
#include "parser.h"
#include "g729.h"
typedef struct G729ParseContext {
ParseContext pc;
int block_size;
int duration;
int remaining;
} G729ParseContext;
static int g729_parse(AVCodecParserContext *s1, AVCodecContext *avctx,
const uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size)
{
G729ParseContext *s = s1->priv_data;
ParseContext *pc = &s->pc;
int next;
if (!s->block_size) {
/* FIXME: replace this heuristic block_size with more precise estimate */
s->block_size = (avctx->bit_rate < 8000) ? G729D_6K4_BLOCK_SIZE : G729_8K_BLOCK_SIZE;
if (avctx->codec_id == AV_CODEC_ID_ACELP_KELVIN)
s->block_size++;
// channels > 2 is invalid, we pass the packet on unchanged
if (avctx->ch_layout.nb_channels > 2)
s->block_size = 0;
s->block_size *= avctx->ch_layout.nb_channels;
s->duration = avctx->frame_size;
}
if (!s->block_size) {
*poutbuf = buf;
*poutbuf_size = buf_size;
return buf_size;
}
if (!s->remaining)
s->remaining = s->block_size;
if (s->remaining <= buf_size) {
next = s->remaining;
s->remaining = 0;
} else {
next = END_NOT_FOUND;
s->remaining -= buf_size;
}
if (ff_combine_frame(pc, next, &buf, &buf_size) < 0 || !buf_size) {
*poutbuf = NULL;
*poutbuf_size = 0;
return buf_size;
}
s1->duration = s->duration;
*poutbuf = buf;
*poutbuf_size = buf_size;
return next;
}
const AVCodecParser ff_g729_parser = {
.codec_ids = { AV_CODEC_ID_G729, AV_CODEC_ID_ACELP_KELVIN },
.priv_data_size = sizeof(G729ParseContext),
.parser_parse = g729_parse,
.parser_close = ff_parse_close,
};