blob: 70440559d23fe67a84ada1b9ca6181b8ca4ba1a6
1 | /* |
2 | * LOAS AudioSyncStream demuxer |
3 | * Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at> |
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/intreadwrite.h" |
23 | #include "libavutil/internal.h" |
24 | #include "avformat.h" |
25 | #include "internal.h" |
26 | #include "rawdec.h" |
27 | |
28 | #define LOAS_SYNC_WORD 0x2b7 |
29 | |
30 | static int loas_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 - 3; |
38 | buf = buf0; |
39 | |
40 | for (; buf < end; buf = buf2 + 1) { |
41 | buf2 = buf; |
42 | |
43 | for (frames = 0; buf2 < end; frames++) { |
44 | uint32_t header = AV_RB24(buf2); |
45 | if ((header >> 13) != LOAS_SYNC_WORD) |
46 | break; |
47 | fsize = (header & 0x1FFF) + 3; |
48 | if (fsize < 7) |
49 | break; |
50 | fsize = FFMIN(fsize, end - buf2); |
51 | buf2 += fsize; |
52 | } |
53 | max_frames = FFMAX(max_frames, frames); |
54 | if (buf == buf0) |
55 | first_frames = frames; |
56 | } |
57 | |
58 | if (first_frames >= 3) |
59 | return AVPROBE_SCORE_EXTENSION + 1; |
60 | else if (max_frames > 100) |
61 | return AVPROBE_SCORE_EXTENSION; |
62 | else if (max_frames >= 3) |
63 | return AVPROBE_SCORE_EXTENSION / 2; |
64 | else |
65 | return 0; |
66 | } |
67 | |
68 | static int loas_read_header(AVFormatContext *s) |
69 | { |
70 | AVStream *st; |
71 | |
72 | st = avformat_new_stream(s, NULL); |
73 | if (!st) |
74 | return AVERROR(ENOMEM); |
75 | |
76 | st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO; |
77 | st->codecpar->codec_id = s->iformat->raw_codec_id; |
78 | st->need_parsing = AVSTREAM_PARSE_FULL_RAW; |
79 | |
80 | //LCM of all possible AAC sample rates |
81 | avpriv_set_pts_info(st, 64, 1, 28224000); |
82 | |
83 | return 0; |
84 | } |
85 | |
86 | AVInputFormat ff_loas_demuxer = { |
87 | .name = "loas", |
88 | .long_name = NULL_IF_CONFIG_SMALL("LOAS AudioSyncStream"), |
89 | .read_probe = loas_probe, |
90 | .read_header = loas_read_header, |
91 | .read_packet = ff_raw_read_partial_packet, |
92 | .flags= AVFMT_GENERIC_INDEX, |
93 | .raw_codec_id = AV_CODEC_ID_AAC_LATM, |
94 | }; |
95 |