libavformat/filmstripdec.c

   1 /*
   2  * Adobe Filmstrip demuxer
   3  * Copyright (c) 2010 Peter Ross
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 /**
  23  * @file
  24  * Adobe Filmstrip demuxer
  25  */
  26
  27 #include "libavutil/intreadwrite.h"
  28 #include "avformat.h"
  29 #include "internal.h"
  30
  31 #define RAND_TAG MKBETAG('R','a','n','d')
  32
  33 typedef struct {
  34     int leading;
  35 } FilmstripDemuxContext;
  36
  37 static int read_header(AVFormatContext *s)
  38 {
  39     FilmstripDemuxContext *film = s->priv_data;
  40     AVIOContext *pb = s->pb;
  41     AVStream *st;
  42
  43     if (!s->pb->seekable)
  44         return AVERROR(EIO);
  45
  46     avio_seek(pb, avio_size(pb) - 36, SEEK_SET);
  47     if (avio_rb32(pb) != RAND_TAG) {
  48         av_log(s, AV_LOG_ERROR, "magic number not found");
  49         return AVERROR_INVALIDDATA;
  50     }
  51
  52     st = avformat_new_stream(s, NULL);
  53     if (!st)
  54         return AVERROR(ENOMEM);
  55
  56     st->nb_frames = avio_rb32(pb);
  57     if (avio_rb16(pb) != 0) {
  58         av_log_ask_for_sample(s, "unsupported packing method\n");
  59         return AVERROR_PATCHWELCOME;
  60     }
  61
  62     avio_skip(pb, 2);
  63     st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
  64     st->codec->codec_id   = AV_CODEC_ID_RAWVIDEO;
  65     st->codec->pix_fmt    = AV_PIX_FMT_RGBA;
  66     st->codec->codec_tag  = 0; /* no fourcc */
  67     st->codec->width      = avio_rb16(pb);
  68     st->codec->height     = avio_rb16(pb);
  69     film->leading         = avio_rb16(pb);
  70     avpriv_set_pts_info(st, 64, 1, avio_rb16(pb));
  71
  72     avio_seek(pb, 0, SEEK_SET);
  73
  74     return 0;
  75 }
  76
  77 static int read_packet(AVFormatContext *s,
  78                        AVPacket *pkt)
  79 {
  80     FilmstripDemuxContext *film = s->priv_data;
  81     AVStream *st = s->streams[0];
  82
  83     if (s->pb->eof_reached)
  84         return AVERROR(EIO);
  85     pkt->dts = avio_tell(s->pb) / (st->codec->width * (st->codec->height + film->leading) * 4);
  86     pkt->size = av_get_packet(s->pb, pkt, st->codec->width * st->codec->height * 4);
  87     avio_skip(s->pb, st->codec->width * film->leading * 4);
  88     if (pkt->size < 0)
  89         return pkt->size;
  90     pkt->flags |= AV_PKT_FLAG_KEY;
  91     return 0;
  92 }
  93
  94 static int read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
  95 {
  96     AVStream *st = s->streams[stream_index];
  97     if (avio_seek(s->pb, FFMAX(timestamp, 0) * st->codec->width * st->codec->height * 4, SEEK_SET) < 0)
  98         return -1;
  99     return 0;
 100 }
 101
 102 AVInputFormat ff_filmstrip_demuxer = {
 103     .name           = "filmstrip",
 104     .long_name      = NULL_IF_CONFIG_SMALL("Adobe Filmstrip"),
 105     .priv_data_size = sizeof(FilmstripDemuxContext),
 106     .read_header    = read_header,
 107     .read_packet    = read_packet,
 108     .read_seek      = read_seek,
 109     .extensions     = "flm",
 110 };