libavformat/mods.c

   1 /*
   2  * MODS demuxer
   3  * Copyright (c) 2015-2016 Florian Nouwt
   4  * Copyright (c) 2017 Adib Surani
   5  * Copyright (c) 2020 Paul B Mahol
   6  *
   7  * This file is part of FFmpeg.
   8  *
   9  * FFmpeg is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * FFmpeg is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with FFmpeg; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23
  24 #include "libavutil/intreadwrite.h"
  25
  26 #include "avformat.h"
  27 #include "demux.h"
  28 #include "internal.h"
  29
  30 static int mods_probe(const AVProbeData *p)
  31 {
  32     if (memcmp(p->buf, "MODSN3\x0a\x00", 8))
  33         return 0;
  34     if (AV_RB32(p->buf + 8) == 0)
  35         return 0;
  36     if (AV_RB32(p->buf + 12) == 0)
  37         return 0;
  38     if (AV_RB32(p->buf + 16) == 0)
  39         return 0;
  40     return AVPROBE_SCORE_MAX;
  41 }
  42
  43 static int mods_read_header(AVFormatContext *s)
  44 {
  45     AVIOContext *pb = s->pb;
  46     AVRational fps;
  47     int64_t pos;
  48
  49     AVStream *st = avformat_new_stream(s, NULL);
  50     if (!st)
  51         return AVERROR(ENOMEM);
  52
  53     avio_skip(pb, 8);
  54
  55     st->nb_frames            = avio_rl32(pb);
  56     st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
  57     st->codecpar->codec_id   = AV_CODEC_ID_MOBICLIP;
  58     st->codecpar->width      = avio_rl32(pb);
  59     st->codecpar->height     = avio_rl32(pb);
  60
  61     fps.num = avio_rl32(pb);
  62     fps.den = 0x1000000;
  63     avpriv_set_pts_info(st, 64, fps.den, fps.num);
  64
  65     avio_skip(pb, 16);
  66
  67     pos = avio_rl32(pb) + 4;
  68     avio_seek(pb, pos, SEEK_SET);
  69     pos = avio_rl32(pb);
  70     avio_seek(pb, pos, SEEK_SET);
  71
  72     return 0;
  73 }
  74
  75 static int mods_read_packet(AVFormatContext *s, AVPacket *pkt)
  76 {
  77     AVIOContext *pb = s->pb;
  78     unsigned size;
  79     int64_t pos;
  80     int ret;
  81
  82     if (avio_feof(pb))
  83         return AVERROR_EOF;
  84
  85     pos = avio_tell(pb);
  86     size = avio_rl32(pb) >> 14;
  87     ret = av_get_packet(pb, pkt, size);
  88     pkt->pos = pos;
  89     pkt->stream_index = 0;
  90     pkt->flags |= AV_PKT_FLAG_KEY;
  91
  92     return ret;
  93 }
  94
  95 const FFInputFormat ff_mods_demuxer = {
  96     .p.name         = "mods",
  97     .p.long_name    = NULL_IF_CONFIG_SMALL("MobiClip MODS"),
  98     .p.extensions   = "mods",
  99     .p.flags        = AVFMT_GENERIC_INDEX,
 100     .read_probe     = mods_probe,
 101     .read_header    = mods_read_header,
 102     .read_packet    = mods_read_packet,
 103 };