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1 | /* |
2 | * AST demuxer | |
3 | * Copyright (c) 2012 Paul B Mahol | |
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/channel_layout.h" | |
23 | #include "libavutil/intreadwrite.h" | |
24 | #include "avformat.h" | |
25 | #include "internal.h" | |
26 | #include "ast.h" | |
27 | ||
28 | static int ast_probe(AVProbeData *p) | |
29 | { | |
30 | if (AV_RL32(p->buf) != MKTAG('S','T','R','M')) | |
31 | return 0; | |
32 | ||
33 | if (!AV_RB16(p->buf + 10) || | |
34 | !AV_RB16(p->buf + 12) || AV_RB16(p->buf + 12) > 256 || | |
35 | !AV_RB32(p->buf + 16) || AV_RB32(p->buf + 16) > 8*48000) | |
36 | return AVPROBE_SCORE_MAX / 8; | |
37 | ||
38 | return AVPROBE_SCORE_MAX / 3 * 2; | |
39 | } | |
40 | ||
41 | static int ast_read_header(AVFormatContext *s) | |
42 | { | |
43 | int depth; | |
44 | AVStream *st; | |
45 | ||
46 | st = avformat_new_stream(s, NULL); | |
47 | if (!st) | |
48 | return AVERROR(ENOMEM); | |
49 | ||
50 | avio_skip(s->pb, 8); | |
51 | st->codec->codec_type = AVMEDIA_TYPE_AUDIO; | |
52 | st->codec->codec_id = ff_codec_get_id(ff_codec_ast_tags, avio_rb16(s->pb)); | |
53 | ||
54 | depth = avio_rb16(s->pb); | |
55 | if (depth != 16) { | |
56 | avpriv_request_sample(s, "depth %d", depth); | |
57 | return AVERROR_INVALIDDATA; | |
58 | } | |
59 | ||
60 | st->codec->channels = avio_rb16(s->pb); | |
61 | if (!st->codec->channels) | |
62 | return AVERROR_INVALIDDATA; | |
63 | ||
64 | if (st->codec->channels == 2) | |
65 | st->codec->channel_layout = AV_CH_LAYOUT_STEREO; | |
66 | else if (st->codec->channels == 4) | |
67 | st->codec->channel_layout = AV_CH_LAYOUT_4POINT0; | |
68 | ||
69 | avio_skip(s->pb, 2); | |
70 | st->codec->sample_rate = avio_rb32(s->pb); | |
71 | if (st->codec->sample_rate <= 0) | |
72 | return AVERROR_INVALIDDATA; | |
73 | st->start_time = 0; | |
74 | st->duration = avio_rb32(s->pb); | |
75 | avio_skip(s->pb, 40); | |
76 | avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate); | |
77 | ||
78 | return 0; | |
79 | } | |
80 | ||
81 | static int ast_read_packet(AVFormatContext *s, AVPacket *pkt) | |
82 | { | |
83 | uint32_t type, size; | |
84 | int64_t pos; | |
85 | int ret; | |
86 | ||
87 | if (avio_feof(s->pb)) | |
88 | return AVERROR_EOF; | |
89 | ||
90 | pos = avio_tell(s->pb); | |
91 | type = avio_rl32(s->pb); | |
92 | size = avio_rb32(s->pb); | |
93 | if (size > INT_MAX / s->streams[0]->codec->channels) | |
94 | return AVERROR_INVALIDDATA; | |
95 | ||
96 | size *= s->streams[0]->codec->channels; | |
97 | if ((ret = avio_skip(s->pb, 24)) < 0) // padding | |
98 | return ret; | |
99 | ||
100 | if (type == MKTAG('B','L','C','K')) { | |
101 | ret = av_get_packet(s->pb, pkt, size); | |
102 | pkt->stream_index = 0; | |
103 | pkt->pos = pos; | |
104 | } else { | |
105 | av_log(s, AV_LOG_ERROR, "unknown chunk %x\n", type); | |
106 | avio_skip(s->pb, size); | |
107 | ret = AVERROR_INVALIDDATA; | |
108 | } | |
109 | ||
110 | return ret; | |
111 | } | |
112 | ||
113 | AVInputFormat ff_ast_demuxer = { | |
114 | .name = "ast", | |
115 | .long_name = NULL_IF_CONFIG_SMALL("AST (Audio Stream)"), | |
116 | .read_probe = ast_probe, | |
117 | .read_header = ast_read_header, | |
118 | .read_packet = ast_read_packet, | |
119 | .extensions = "ast", | |
120 | .flags = AVFMT_GENERIC_INDEX, | |
121 | .codec_tag = (const AVCodecTag* const []){ff_codec_ast_tags, 0}, | |
122 | }; |