1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
|
/*
* RAW AC-3 and E-AC-3 demuxer
* Copyright (c) 2007 Justin Ruggles <justin.ruggles@gmail.com>
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/crc.h"
#include "libavcodec/ac3_parser.h"
#include "avformat.h"
#include "rawdec.h"
static int ac3_eac3_probe(AVProbeData *p, enum CodecID expected_codec_id)
{
int max_frames, first_frames = 0, frames;
uint8_t *buf, *buf2, *end;
AC3HeaderInfo hdr;
GetBitContext gbc;
enum CodecID codec_id = CODEC_ID_AC3;
max_frames = 0;
buf = p->buf;
end = buf + p->buf_size;
for(; buf < end; buf++) {
buf2 = buf;
for(frames = 0; buf2 < end; frames++) {
init_get_bits(&gbc, buf2, 54);
if(ff_ac3_parse_header(&gbc, &hdr) < 0)
break;
if(buf2 + hdr.frame_size > end ||
av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, buf2 + 2, hdr.frame_size - 2))
break;
if (hdr.bitstream_id > 10)
codec_id = CODEC_ID_EAC3;
buf2 += hdr.frame_size;
}
max_frames = FFMAX(max_frames, frames);
if(buf == p->buf)
first_frames = frames;
}
if(codec_id != expected_codec_id) return 0;
// keep this in sync with mp3 probe, both need to avoid
// issues with MPEG-files!
if (first_frames>=4) return AVPROBE_SCORE_MAX/2+1;
else if(max_frames>500)return AVPROBE_SCORE_MAX/2;
else if(max_frames>=4) return AVPROBE_SCORE_MAX/4;
else if(max_frames>=1) return 1;
else return 0;
}
#if CONFIG_AC3_DEMUXER
static int ac3_probe(AVProbeData *p)
{
return ac3_eac3_probe(p, CODEC_ID_AC3);
}
AVInputFormat ff_ac3_demuxer = {
"ac3",
NULL_IF_CONFIG_SMALL("raw AC-3"),
0,
ac3_probe,
ff_raw_audio_read_header,
ff_raw_read_partial_packet,
.flags= AVFMT_GENERIC_INDEX,
.extensions = "ac3",
.value = CODEC_ID_AC3,
};
#endif
#if CONFIG_EAC3_DEMUXER
static int eac3_probe(AVProbeData *p)
{
return ac3_eac3_probe(p, CODEC_ID_EAC3);
}
AVInputFormat ff_eac3_demuxer = {
"eac3",
NULL_IF_CONFIG_SMALL("raw E-AC-3"),
0,
eac3_probe,
ff_raw_audio_read_header,
ff_raw_read_partial_packet,
.flags= AVFMT_GENERIC_INDEX,
.extensions = "eac3",
.value = CODEC_ID_EAC3,
};
#endif
|
