aac_ac3_parser.c 2.8 KB
Newer Older
1
/*
2
 * Common AAC and AC-3 parser
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
 * Copyright (c) 2003 Fabrice Bellard.
 * Copyright (c) 2003 Michael Niedermayer.
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "parser.h"
#include "aac_ac3_parser.h"

26
int ff_aac_ac3_parse(AVCodecParserContext *s1,
27 28 29 30
                     AVCodecContext *avctx,
                     const uint8_t **poutbuf, int *poutbuf_size,
                     const uint8_t *buf, int buf_size)
{
31
    AACAC3ParseContext *s = s1->priv_data;
32 33
    ParseContext *pc = &s->pc;
    int len, i;
34
    int new_frame_start;
35

36
get_next:
37 38
    i=END_NOT_FOUND;
    if(s->remaining_size <= buf_size){
39
        if(s->remaining_size && !s->need_next_header){
40 41 42 43 44 45
            i= s->remaining_size;
            s->remaining_size = 0;
        }else{ //we need a header first
            len=0;
            for(i=s->remaining_size; i<buf_size; i++){
                s->state = (s->state<<8) + buf[i];
46
                if((len=s->sync(s->state, s, &s->need_next_header, &new_frame_start)))
47 48 49 50 51 52
                    break;
            }
            if(len<=0){
                i=END_NOT_FOUND;
            }else{
                i-= s->header_size -1;
53
                s->remaining_size = len;
54 55
                if(!new_frame_start){
                    s->remaining_size += i;
56
                    goto get_next;
57
                }
58 59 60
            }
        }
    }
61

62 63 64 65 66 67
    if(ff_combine_frame(pc, i, &buf, &buf_size)<0){
        s->remaining_size -= FFMIN(s->remaining_size, buf_size);
        *poutbuf = NULL;
        *poutbuf_size = 0;
        return buf_size;
    }
68

69 70
    *poutbuf = buf;
    *poutbuf_size = buf_size;
71

Michael Niedermayer's avatar
Michael Niedermayer committed
72 73
    /* update codec info */
    avctx->sample_rate = s->sample_rate;
74
    /* allow downmixing to stereo (or mono for AC-3) */
Michael Niedermayer's avatar
Michael Niedermayer committed
75 76 77 78 79 80 81 82 83 84 85
    if(avctx->request_channels > 0 &&
            avctx->request_channels < s->channels &&
            (avctx->request_channels <= 2 ||
            (avctx->request_channels == 1 &&
            avctx->codec_id == CODEC_ID_AC3))) {
        avctx->channels = avctx->request_channels;
    } else {
        avctx->channels = s->channels;
    }
    avctx->bit_rate = s->bit_rate;
    avctx->frame_size = s->samples;
86 87

    return i;
88
}