64ee767b14c89109a3ff06b3ed259cb82d95678e
[libav.git] / libavcodec / aac_ac3_parser.c
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
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)
30 {
31 AACAC3ParseContext *s = s1->priv_data;
32 ParseContext *pc = &s->pc;
33 int len, i;
34 int new_frame_start;
35
36 get_next:
37 i=END_NOT_FOUND;
38 if(s->remaining_size <= buf_size){
39 if(s->remaining_size && !s->need_next_header){
40 i= s->remaining_size;
41 s->remaining_size = 0;
42 }else{ //we need a header first
43 len=0;
44 for(i=s->remaining_size; i<buf_size; i++){
45 s->state = (s->state<<8) + buf[i];
46 if((len=s->sync(s->state, s, &s->need_next_header, &new_frame_start)))
47 break;
48 }
49 if(len<=0){
50 i=END_NOT_FOUND;
51 }else{
52 i-= s->header_size -1;
53 s->remaining_size = len;
54 if(!new_frame_start)
55 goto get_next;
56 }
57 }
58 }
59
60 if(ff_combine_frame(pc, i, &buf, &buf_size)<0){
61 s->remaining_size -= FFMIN(s->remaining_size, buf_size);
62 *poutbuf = NULL;
63 *poutbuf_size = 0;
64 return buf_size;
65 }
66
67 *poutbuf = buf;
68 *poutbuf_size = buf_size;
69
70 /* update codec info */
71 avctx->sample_rate = s->sample_rate;
72 /* allow downmixing to stereo (or mono for AC3) */
73 if(avctx->request_channels > 0 &&
74 avctx->request_channels < s->channels &&
75 (avctx->request_channels <= 2 ||
76 (avctx->request_channels == 1 &&
77 avctx->codec_id == CODEC_ID_AC3))) {
78 avctx->channels = avctx->request_channels;
79 } else {
80 avctx->channels = s->channels;
81 }
82 avctx->bit_rate = s->bit_rate;
83 avctx->frame_size = s->samples;
84
85 return i;
86 }