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2ba45a60 DM |
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 FFmpeg. | |
7 | * | |
8 | * FFmpeg 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 | * FFmpeg 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 FFmpeg; 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 | #include "apetag.h" | |
29 | ||
30 | static int adts_aac_probe(AVProbeData *p) | |
31 | { | |
32 | int max_frames = 0, first_frames = 0; | |
33 | int fsize, frames; | |
34 | const uint8_t *buf0 = p->buf; | |
35 | const uint8_t *buf2; | |
36 | const uint8_t *buf; | |
37 | const 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 | if (buf != buf0) { | |
48 | // Found something that isn't an ADTS header, starting | |
49 | // from a position other than the start of the buffer. | |
50 | // Discard the count we've accumulated so far since it | |
51 | // probably was a false positive. | |
52 | frames = 0; | |
53 | } | |
54 | break; | |
55 | } | |
56 | fsize = (AV_RB32(buf2 + 3) >> 13) & 0x1FFF; | |
57 | if (fsize < 7) | |
58 | break; | |
59 | fsize = FFMIN(fsize, end - buf2); | |
60 | buf2 += fsize; | |
61 | } | |
62 | max_frames = FFMAX(max_frames, frames); | |
63 | if (buf == buf0) | |
64 | first_frames = frames; | |
65 | } | |
66 | ||
67 | if (first_frames >= 3) | |
68 | return AVPROBE_SCORE_EXTENSION + 1; | |
69 | else if (max_frames > 100) | |
70 | return AVPROBE_SCORE_EXTENSION; | |
71 | else if (max_frames >= 3) | |
72 | return AVPROBE_SCORE_EXTENSION / 2; | |
73 | else if (max_frames >= 1) | |
74 | return 1; | |
75 | else | |
76 | return 0; | |
77 | } | |
78 | ||
79 | static int adts_aac_read_header(AVFormatContext *s) | |
80 | { | |
81 | AVStream *st; | |
82 | ||
83 | st = avformat_new_stream(s, NULL); | |
84 | if (!st) | |
85 | return AVERROR(ENOMEM); | |
86 | ||
87 | st->codec->codec_type = AVMEDIA_TYPE_AUDIO; | |
88 | st->codec->codec_id = s->iformat->raw_codec_id; | |
89 | st->need_parsing = AVSTREAM_PARSE_FULL_RAW; | |
90 | ||
91 | ff_id3v1_read(s); | |
92 | if (s->pb->seekable && | |
93 | !av_dict_get(s->metadata, "", NULL, AV_DICT_IGNORE_SUFFIX)) { | |
94 | int64_t cur = avio_tell(s->pb); | |
95 | ff_ape_parse_tag(s); | |
96 | avio_seek(s->pb, cur, SEEK_SET); | |
97 | } | |
98 | ||
99 | // LCM of all possible ADTS sample rates | |
100 | avpriv_set_pts_info(st, 64, 1, 28224000); | |
101 | ||
102 | return 0; | |
103 | } | |
104 | ||
105 | AVInputFormat ff_aac_demuxer = { | |
106 | .name = "aac", | |
107 | .long_name = NULL_IF_CONFIG_SMALL("raw ADTS AAC (Advanced Audio Coding)"), | |
108 | .read_probe = adts_aac_probe, | |
109 | .read_header = adts_aac_read_header, | |
110 | .read_packet = ff_raw_read_partial_packet, | |
111 | .flags = AVFMT_GENERIC_INDEX, | |
112 | .extensions = "aac", | |
113 | .mime_type = "audio/aac,audio/aacp,audio/x-aac", | |
114 | .raw_codec_id = AV_CODEC_ID_AAC, | |
115 | }; |