2 * RAW AC-3 and E-AC-3 demuxer
3 * Copyright (c) 2007 Justin Ruggles <justin.ruggles@gmail.com>
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 #include "libavutil/crc.h"
23 #include "libavcodec/ac3_parser.h"
27 static int ac3_eac3_probe(AVProbeData
*p
, enum AVCodecID expected_codec_id
)
29 int max_frames
, first_frames
= 0, frames
;
30 const uint8_t *buf
, *buf2
, *end
;
31 AC3HeaderInfo
*phdr
= NULL
;
33 enum AVCodecID codec_id
= AV_CODEC_ID_AC3
;
37 end
= buf
+ p
->buf_size
;
39 for(; buf
< end
; buf
++) {
40 if(buf
> p
->buf
&& !(buf
[0] == 0x0B && buf
[1] == 0x77)
41 && !(buf
[0] == 0x77 && buf
[1] == 0x0B) )
45 for(frames
= 0; buf2
< end
; frames
++) {
48 if(!memcmp(buf2
, "\x1\x10\0\0\0\0\0\0", 8))
50 if (buf
[0] == 0x77 && buf
[1] == 0x0B) {
55 init_get_bits(&gbc
, buf3
, 54);
57 init_get_bits(&gbc
, buf2
, 54);
58 if(avpriv_ac3_parse_header2(&gbc
, &phdr
) < 0)
60 if(buf2
+ phdr
->frame_size
> end
)
62 if (buf
[0] == 0x77 && buf
[1] == 0x0B) {
63 av_assert0(phdr
->frame_size
<= sizeof(buf3
));
64 for(i
=8; i
<phdr
->frame_size
; i
+=2) {
69 if(av_crc(av_crc_get_table(AV_CRC_16_ANSI
), 0, gbc
.buffer
+ 2, phdr
->frame_size
- 2))
71 if (phdr
->bitstream_id
> 10)
72 codec_id
= AV_CODEC_ID_EAC3
;
73 buf2
+= phdr
->frame_size
;
75 max_frames
= FFMAX(max_frames
, frames
);
77 first_frames
= frames
;
80 if(codec_id
!= expected_codec_id
) return 0;
81 // keep this in sync with mp3 probe, both need to avoid
82 // issues with MPEG-files!
83 if (first_frames
>=4) return AVPROBE_SCORE_EXTENSION
+ 1;
84 else if(max_frames
>200)return AVPROBE_SCORE_EXTENSION
;
85 else if(max_frames
>=4) return AVPROBE_SCORE_EXTENSION
/2;
86 else if(max_frames
>=1) return 1;
90 #if CONFIG_AC3_DEMUXER
91 static int ac3_probe(AVProbeData
*p
)
93 return ac3_eac3_probe(p
, AV_CODEC_ID_AC3
);
96 AVInputFormat ff_ac3_demuxer
= {
98 .long_name
= NULL_IF_CONFIG_SMALL("raw AC-3"),
99 .read_probe
= ac3_probe
,
100 .read_header
= ff_raw_audio_read_header
,
101 .read_packet
= ff_raw_read_partial_packet
,
102 .flags
= AVFMT_GENERIC_INDEX
,
104 .raw_codec_id
= AV_CODEC_ID_AC3
,
108 #if CONFIG_EAC3_DEMUXER
109 static int eac3_probe(AVProbeData
*p
)
111 return ac3_eac3_probe(p
, AV_CODEC_ID_EAC3
);
114 AVInputFormat ff_eac3_demuxer
= {
116 .long_name
= NULL_IF_CONFIG_SMALL("raw E-AC-3"),
117 .read_probe
= eac3_probe
,
118 .read_header
= ff_raw_audio_read_header
,
119 .read_packet
= ff_raw_read_partial_packet
,
120 .flags
= AVFMT_GENERIC_INDEX
,
121 .extensions
= "eac3",
122 .raw_codec_id
= AV_CODEC_ID_EAC3
,