1/*
2 * Common AAC and AC-3 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 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
36get_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                s->state=0;
53                i-= s->header_size -1;
54                s->remaining_size = len;
55                if(!new_frame_start || pc->index+i<=0){
56                    s->remaining_size += i;
57                    goto get_next;
58                }
59            }
60        }
61    }
62
63    if(ff_combine_frame(pc, i, &buf, &buf_size)<0){
64        s->remaining_size -= FFMIN(s->remaining_size, buf_size);
65        *poutbuf = NULL;
66        *poutbuf_size = 0;
67        return buf_size;
68    }
69
70    *poutbuf = buf;
71    *poutbuf_size = buf_size;
72
73    /* update codec info */
74    avctx->sample_rate = s->sample_rate;
75    if(s->codec_id)
76        avctx->codec_id = s->codec_id;
77
78    /* allow downmixing to stereo (or mono for AC-3) */
79    if(avctx->request_channels > 0 &&
80            avctx->request_channels < s->channels &&
81            (avctx->request_channels <= 2 ||
82            (avctx->request_channels == 1 &&
83            (avctx->codec_id == CODEC_ID_AC3 ||
84             avctx->codec_id == CODEC_ID_EAC3)))) {
85        avctx->channels = avctx->request_channels;
86    } else {
87        avctx->channels = s->channels;
88    }
89    avctx->bit_rate = s->bit_rate;
90    avctx->frame_size = s->samples;
91
92    return i;
93}
94