| 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 | }; |