2 * Common AAC and AC3 parser
3 * Copyright (c) 2003 Fabrice Bellard.
4 * Copyright (c) 2003 Michael Niedermayer.
6 * This file is part of FFmpeg.
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 #include "aac_ac3_parser.h"
26 int ff_aac_ac3_parse(AVCodecParserContext *s1,
27 AVCodecContext *avctx,
28 const uint8_t **poutbuf, int *poutbuf_size,
29 const uint8_t *buf, int buf_size)
31 AACAC3ParseContext *s = s1->priv_data;
32 const uint8_t *buf_ptr;
33 int len, sample_rate, bit_rate, channels, samples;
39 while (buf_size > 0) {
40 int size_needed= s->frame_size ? s->frame_size : s->header_size;
41 len = s->inbuf_ptr - s->inbuf;
44 len = FFMIN(size_needed - len, buf_size);
45 memcpy(s->inbuf_ptr, buf_ptr, len);
51 if (s->frame_size == 0) {
52 if ((s->inbuf_ptr - s->inbuf) == s->header_size) {
53 len = s->sync(s->inbuf, &channels, &sample_rate, &bit_rate,
56 /* no sync found : move by one byte (inefficient, but simple!) */
57 memmove(s->inbuf, s->inbuf + 1, s->header_size - 1);
61 /* update codec info */
62 avctx->sample_rate = sample_rate;
63 /* allow downmixing to stereo (or mono for AC3) */
64 if(avctx->request_channels > 0 &&
65 avctx->request_channels < channels &&
66 (avctx->request_channels <= 2 ||
67 (avctx->request_channels == 1 &&
68 avctx->codec_id == CODEC_ID_AC3))) {
69 avctx->channels = avctx->request_channels;
71 avctx->channels = channels;
73 avctx->bit_rate = bit_rate;
74 avctx->frame_size = samples;
78 if(s->inbuf_ptr - s->inbuf == s->frame_size){
80 *poutbuf_size = s->frame_size;
81 s->inbuf_ptr = s->inbuf;