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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 ] = buf[i+1]; | |
53 | buf3[i+1] = buf[i ]; | |
54 | } | |
55 | init_get_bits(&gbc, buf3, 54); | |
56 | }else | |
57 | init_get_bits(&gbc, buf2, 54); | |
58 | if(avpriv_ac3_parse_header2(&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 ] = buf[i+1]; | |
66 | buf3[i+1] = buf[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>=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; | |
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 |