blob: e85b0ac7c9e20c72eb08c0d7397288298989fbc9
1 | /* |
2 | * RAW AC-3 and E-AC-3 demuxer |
3 | * Copyright (c) 2007 Justin Ruggles <justin.ruggles@gmail.com> |
4 | * |
5 | * This file is part of FFmpeg. |
6 | * |
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. |
11 | * |
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. |
16 | * |
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 |
20 | */ |
21 | |
22 | #include "libavutil/crc.h" |
23 | #include "libavcodec/ac3_parser.h" |
24 | #include "avformat.h" |
25 | #include "rawdec.h" |
26 | |
27 | static int ac3_eac3_probe(AVProbeData *p, enum AVCodecID expected_codec_id) |
28 | { |
29 | int max_frames, first_frames = 0, frames; |
30 | const uint8_t *buf, *buf2, *end; |
31 | AC3HeaderInfo *phdr = NULL; |
32 | GetBitContext gbc; |
33 | enum AVCodecID codec_id = AV_CODEC_ID_AC3; |
34 | |
35 | max_frames = 0; |
36 | buf = p->buf; |
37 | end = buf + p->buf_size; |
38 | |
39 | for(; buf < end; buf++) { |
40 | if(buf > p->buf && !(buf[0] == 0x0B && buf[1] == 0x77) |
41 | && !(buf[0] == 0x77 && buf[1] == 0x0B) ) |
42 | continue; |
43 | buf2 = buf; |
44 | |
45 | for(frames = 0; buf2 < end; frames++) { |
46 | uint8_t buf3[4096]; |
47 | int i; |
48 | if(!memcmp(buf2, "\x1\x10\0\0\0\0\0\0", 8)) |
49 | buf2+=16; |
50 | if (buf[0] == 0x77 && buf[1] == 0x0B) { |
51 | for(i=0; i<8; i+=2) { |
52 | buf3[i ] = buf2[i+1]; |
53 | buf3[i+1] = buf2[i ]; |
54 | } |
55 | init_get_bits(&gbc, buf3, 54); |
56 | }else |
57 | init_get_bits(&gbc, buf2, 54); |
58 | if(avpriv_ac3_parse_header(&gbc, &phdr) < 0) |
59 | break; |
60 | if(buf2 + phdr->frame_size > end) |
61 | break; |
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) { |
65 | buf3[i ] = buf2[i+1]; |
66 | buf3[i+1] = buf2[i ]; |
67 | } |
68 | } |
69 | if(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, gbc.buffer + 2, phdr->frame_size - 2)) |
70 | break; |
71 | if (phdr->bitstream_id > 10) |
72 | codec_id = AV_CODEC_ID_EAC3; |
73 | buf2 += phdr->frame_size; |
74 | } |
75 | max_frames = FFMAX(max_frames, frames); |
76 | if(buf == p->buf) |
77 | first_frames = frames; |
78 | } |
79 | av_freep(&phdr); |
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>=7) 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; |
87 | else return 0; |
88 | } |
89 | |
90 | #if CONFIG_AC3_DEMUXER |
91 | static int ac3_probe(AVProbeData *p) |
92 | { |
93 | return ac3_eac3_probe(p, AV_CODEC_ID_AC3); |
94 | } |
95 | |
96 | AVInputFormat ff_ac3_demuxer = { |
97 | .name = "ac3", |
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, |
103 | .extensions = "ac3", |
104 | .raw_codec_id = AV_CODEC_ID_AC3, |
105 | }; |
106 | #endif |
107 | |
108 | #if CONFIG_EAC3_DEMUXER |
109 | static int eac3_probe(AVProbeData *p) |
110 | { |
111 | return ac3_eac3_probe(p, AV_CODEC_ID_EAC3); |
112 | } |
113 | |
114 | AVInputFormat ff_eac3_demuxer = { |
115 | .name = "eac3", |
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, |
123 | }; |
124 | #endif |
125 |