move aac and ac3 parsers in their own files
[libav.git] / libavcodec / aac_ac3_parser.c
CommitLineData
99ff31dc
AJ
1/*
2 * Common AAC and AC3 parser
3 * Copyright (c) 2003 Fabrice Bellard.
4 * Copyright (c) 2003 Michael Niedermayer.
5 *
6 * This file is part of FFmpeg.
7 *
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.
12 *
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.
17 *
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
21 */
22
23#include "parser.h"
24#include "aac_ac3_parser.h"
25
26int ac3_parse(AVCodecParserContext *s1,
27 AVCodecContext *avctx,
28 const uint8_t **poutbuf, int *poutbuf_size,
29 const uint8_t *buf, int buf_size)
30{
31 AC3ParseContext *s = s1->priv_data;
32 const uint8_t *buf_ptr;
33 int len, sample_rate, bit_rate, channels, samples;
34
35 *poutbuf = NULL;
36 *poutbuf_size = 0;
37
38 buf_ptr = buf;
39 while (buf_size > 0) {
40 len = s->inbuf_ptr - s->inbuf;
41 if (s->frame_size == 0) {
42 /* no header seen : find one. We need at least s->header_size
43 bytes to parse it */
44 len = FFMIN(s->header_size - len, buf_size);
45
46 memcpy(s->inbuf_ptr, buf_ptr, len);
47 buf_ptr += len;
48 s->inbuf_ptr += len;
49 buf_size -= len;
50 if ((s->inbuf_ptr - s->inbuf) == s->header_size) {
51 len = s->sync(s->inbuf, &channels, &sample_rate, &bit_rate,
52 &samples);
53 if (len == 0) {
54 /* no sync found : move by one byte (inefficient, but simple!) */
55 memmove(s->inbuf, s->inbuf + 1, s->header_size - 1);
56 s->inbuf_ptr--;
57 } else {
58 s->frame_size = len;
59 /* update codec info */
60 avctx->sample_rate = sample_rate;
61 /* set channels,except if the user explicitly requests 1 or 2 channels, XXX/FIXME this is a bit ugly */
62 if(avctx->codec_id == CODEC_ID_AC3){
63 if(avctx->channels!=1 && avctx->channels!=2){
64 avctx->channels = channels;
65 }
66 } else {
67 avctx->channels = channels;
68 }
69 avctx->bit_rate = bit_rate;
70 avctx->frame_size = samples;
71 }
72 }
73 } else {
74 len = FFMIN(s->frame_size - len, buf_size);
75
76 memcpy(s->inbuf_ptr, buf_ptr, len);
77 buf_ptr += len;
78 s->inbuf_ptr += len;
79 buf_size -= len;
80
81 if(s->inbuf_ptr - s->inbuf == s->frame_size){
82 *poutbuf = s->inbuf;
83 *poutbuf_size = s->frame_size;
84 s->inbuf_ptr = s->inbuf;
85 s->frame_size = 0;
86 break;
87 }
88 }
89 }
90 return buf_ptr - buf;
91}