1/*
2 * raw ADTS AAC demuxer
3 * Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at>
4 * Copyright (c) 2009 Robert Swain ( rob opendot cl )
5 *
6 * This file is part of Libav.
7 *
8 * Libav 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 * Libav 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 Libav; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23#include "libavutil/intreadwrite.h"
24#include "avformat.h"
25#include "internal.h"
26#include "rawdec.h"
27#include "id3v1.h"
28
29
30static int adts_aac_probe(AVProbeData *p)
31{
32    int max_frames = 0, first_frames = 0;
33    int fsize, frames;
34    uint8_t *buf0 = p->buf;
35    uint8_t *buf2;
36    uint8_t *buf;
37    uint8_t *end = buf0 + p->buf_size - 7;
38
39    buf = buf0;
40
41    for(; buf < end; buf= buf2+1) {
42        buf2 = buf;
43
44        for(frames = 0; buf2 < end; frames++) {
45            uint32_t header = AV_RB16(buf2);
46            if((header&0xFFF6) != 0xFFF0)
47                break;
48            fsize = (AV_RB32(buf2 + 3) >> 13) & 0x1FFF;
49            if(fsize < 7)
50                break;
51            buf2 += fsize;
52        }
53        max_frames = FFMAX(max_frames, frames);
54        if(buf == buf0)
55            first_frames= frames;
56    }
57    if   (first_frames>=3) return AVPROBE_SCORE_MAX/2+1;
58    else if(max_frames>500)return AVPROBE_SCORE_MAX/2;
59    else if(max_frames>=3) return AVPROBE_SCORE_MAX/4;
60    else if(max_frames>=1) return 1;
61    else                   return 0;
62}
63
64static int adts_aac_read_header(AVFormatContext *s,
65                                AVFormatParameters *ap)
66{
67    AVStream *st;
68
69    st = avformat_new_stream(s, NULL);
70    if (!st)
71        return AVERROR(ENOMEM);
72
73    st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
74    st->codec->codec_id = s->iformat->value;
75    st->need_parsing = AVSTREAM_PARSE_FULL;
76
77    ff_id3v1_read(s);
78
79    //LCM of all possible ADTS sample rates
80    avpriv_set_pts_info(st, 64, 1, 28224000);
81
82    return 0;
83}
84
85AVInputFormat ff_aac_demuxer = {
86    .name           = "aac",
87    .long_name      = NULL_IF_CONFIG_SMALL("raw ADTS AAC"),
88    .read_probe     = adts_aac_probe,
89    .read_header    = adts_aac_read_header,
90    .read_packet    = ff_raw_read_partial_packet,
91    .flags= AVFMT_GENERIC_INDEX,
92    .extensions = "aac",
93    .value = CODEC_ID_AAC,
94};
95