Corrections of errors in aac_ac3_parser
[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
35 while(s->remaining_size <= buf_size){
36 if(s->remaining_size && !s->need_next_header){
37 i= s->remaining_size;
38 s->remaining_size = 0;
39 goto output_frame;
40 }else{ //we need a header first
41 len=0;
42 for(i=s->remaining_size; i<buf_size; i++){
43 s->state = (s->state<<8) + buf[i];
44 if((len=s->sync(s->state, s, &s->need_next_header, &s->new_frame_start)))
45 break;
46 }
47 i-= s->header_size -1;
48 if(len>0){
49 s->remaining_size = len + i;
50
51 if(pc->index+i > 0 && s->new_frame_start){
52 s->remaining_size -= i; // remaining_size=len
53 output_frame:
54 if(!s->frame_in_buffer && 0){
55 s->frame_in_buffer=1;
56 buf+=i;
57 buf_size-=i;
58 continue;
59 }
60 ff_combine_frame(pc, i, &buf, &buf_size);
61 *poutbuf = buf;
62 *poutbuf_size = buf_size;
63
64 /* update codec info */
65 avctx->sample_rate = s->sample_rate;
66 /* allow downmixing to stereo (or mono for AC3) */
67 if(avctx->request_channels > 0 &&
68 avctx->request_channels < s->channels &&
69 (avctx->request_channels <= 2 ||
70 (avctx->request_channels == 1 &&
71 avctx->codec_id == CODEC_ID_AC3))) {
72 avctx->channels = avctx->request_channels;
73 } else {
74 avctx->channels = s->channels;
75 }
76 avctx->bit_rate = s->bit_rate;
77 avctx->frame_size = s->samples;
78
79 return i;
80 }
81 s->frame_in_buffer=1;
82 }else{
83 break;
84 }
85 }
86 }
87
88 ff_combine_frame(pc, END_NOT_FOUND, &buf, &buf_size);
89 s->remaining_size -= FFMIN(s->remaining_size, buf_size);
90 *poutbuf = NULL;
91 *poutbuf_size = 0;
92 return buf_size;
93 }