librempeg/libavcodec/gsm_parser.c
Justin Ruggles 82390f57d1 avcodec: add GSM parser
The WAVE demuxer returns packets with many blocks per frame, which needs to be
parsed into single blocks. This has a side-effect of fixing the timestamps.
2012-01-11 08:56:24 -05:00

80 lines
2.2 KiB
C

/*
* Copyright (c) 2012 Justin Ruggles
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* GSM audio parser
*
* Splits packets into individual blocks.
*/
#include "parser.h"
#include "gsm.h"
typedef struct GSMParseContext {
ParseContext pc;
int block_size;
int remaining;
} GSMParseContext;
static int gsm_parse(AVCodecParserContext *s1, AVCodecContext *avctx,
const uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size)
{
GSMParseContext *s = s1->priv_data;
ParseContext *pc = &s->pc;
int next;
if (!s->block_size) {
switch (avctx->codec_id) {
case CODEC_ID_GSM: s->block_size = GSM_BLOCK_SIZE; break;
case CODEC_ID_GSM_MS: s->block_size = GSM_MS_BLOCK_SIZE; break;
default:
return AVERROR(EINVAL);
}
}
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;
}
*poutbuf = buf;
*poutbuf_size = buf_size;
return next;
}
AVCodecParser ff_gsm_parser = {
.codec_ids = { CODEC_ID_GSM, CODEC_ID_GSM_MS },
.priv_data_size = sizeof(GSMParseContext),
.parser_parse = gsm_parse,
.parser_close = ff_parse_close,
};