/*
  * Adobe Filmstrip demuxer
  * Copyright (c) 2010 Peter Ross
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 /**

  * @file

  * Adobe Filmstrip demuxer
  */
 
 #include "libavutil/intreadwrite.h"
 #include "avformat.h"

 #include "internal.h"

 
 #define RAND_TAG MKBETAG('R','a','n','d')
 
 typedef struct {
     int leading;
 } FilmstripDemuxContext;
 

 static int read_header(AVFormatContext *s)

 {
     FilmstripDemuxContext *film = s->priv_data;

     AVIOContext *pb = s->pb;

     AVStream *st;
 

     if (!s->pb->seekable)

         return AVERROR(EIO);
 

     avio_seek(pb, avio_size(pb) - 36, SEEK_SET);

     if (avio_rb32(pb) != RAND_TAG) {

         av_log(s, AV_LOG_ERROR, "magic number not found\n");

         return AVERROR_INVALIDDATA;
     }
 

     st = avformat_new_stream(s, NULL);

     if (!st)
         return AVERROR(ENOMEM);
 

     st->nb_frames = avio_rb32(pb);
     if (avio_rb16(pb) != 0) {

         avpriv_request_sample(s, "Unsupported packing method");

         return AVERROR_PATCHWELCOME;

     }
 

     avio_skip(pb, 2);

     st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

     st->codec->codec_id   = AV_CODEC_ID_RAWVIDEO;

     st->codec->pix_fmt    = AV_PIX_FMT_RGBA;

     st->codec->codec_tag  = 0; /* no fourcc */

     st->codec->width      = avio_rb16(pb);
     st->codec->height     = avio_rb16(pb);
     film->leading         = avio_rb16(pb);

     avpriv_set_pts_info(st, 64, 1, avio_rb16(pb));

     avio_seek(pb, 0, SEEK_SET);

 
     return 0;
 }
 
 static int read_packet(AVFormatContext *s,
                        AVPacket *pkt)
 {
     FilmstripDemuxContext *film = s->priv_data;
     AVStream *st = s->streams[0];
 
     if (url_feof(s->pb))
         return AVERROR(EIO);

     pkt->dts = avio_tell(s->pb) / (st->codec->width * (st->codec->height + film->leading) * 4);

     pkt->size = av_get_packet(s->pb, pkt, st->codec->width * st->codec->height * 4);

     avio_skip(s->pb, st->codec->width * film->leading * 4);

     if (pkt->size < 0)
         return pkt->size;

     pkt->flags |= AV_PKT_FLAG_KEY;

     return 0;
 }
 
 static int read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
 {
     AVStream *st = s->streams[stream_index];

     if (avio_seek(s->pb, FFMAX(timestamp, 0) * st->codec->width * st->codec->height * 4, SEEK_SET) < 0)
         return -1;

     return 0;
 }
 

 AVInputFormat ff_filmstrip_demuxer = {

     .name           = "filmstrip",
     .long_name      = NULL_IF_CONFIG_SMALL("Adobe Filmstrip"),
     .priv_data_size = sizeof(FilmstripDemuxContext),
     .read_header    = read_header,
     .read_packet    = read_packet,
     .read_seek      = read_seek,

     .extensions     = "flm",

 };