/*
  * Metar Gear Solid: The Twin Snakes demuxer
  * Copyright (c) 2012 Paul B Mahol
  *
  * 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
  */
 
 #include "libavutil/intreadwrite.h"
 #include "libavutil/intfloat.h"
 #include "avformat.h"
 #include "riff.h"
 
 static int read_probe(AVProbeData *p)
 {
     if (AV_RB32(p->buf     ) != 0x000E ||
         AV_RB32(p->buf +  4) != 0x0050 ||
         AV_RB32(p->buf + 12) != 0x0034)
         return 0;
     return AVPROBE_SCORE_MAX;
 }
 
 static int read_header(AVFormatContext *s)
 {
     AVIOContext *pb = s->pb;
     AVStream    *st;
     AVRational  fps;
     uint32_t chunk_size;
 
     avio_skip(pb, 4);
     chunk_size = avio_rb32(pb);
     if (chunk_size != 80)
         return AVERROR(EIO);
     avio_skip(pb, 20);
 
     st = avformat_new_stream(s, 0);
     if (!st)
         return AVERROR(ENOMEM);
 

     st->need_parsing = AVSTREAM_PARSE_HEADERS;

     st->start_time = 0;
     st->nb_frames  =
     st->duration   = avio_rb32(pb);
     fps = av_d2q(av_int2float(avio_rb32(pb)), INT_MAX);
     st->codec->width  = avio_rb32(pb);
     st->codec->height = avio_rb32(pb);
     avio_skip(pb, 12);
     st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
     st->codec->codec_tag  = avio_rb32(pb);
     st->codec->codec_id   = ff_codec_get_id(ff_codec_bmp_tags,
                                             st->codec->codec_tag);
     avpriv_set_pts_info(st, 64, fps.den, fps.num);
     avio_skip(pb, 20);
 
     return 0;
 }
 
 static int read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     AVIOContext *pb = s->pb;
     uint32_t chunk_size, payload_size;
     int ret;
 
     if (url_feof(pb))
         return AVERROR_EOF;
 
     avio_skip(pb, 4);
     chunk_size = avio_rb32(pb);
     avio_skip(pb, 4);
     payload_size = avio_rb32(pb);
 
     if (chunk_size < payload_size + 16)
         return AVERROR(EIO);
 
     ret = av_get_packet(pb, pkt, payload_size);
     if (ret < 0)
         return ret;
 

     pkt->pos -= 16;

     pkt->duration = 1;
     avio_skip(pb, chunk_size - (ret + 16));
 
     return ret;
 }
 
 AVInputFormat ff_mgsts_demuxer = {
     .name        = "mgsts",
     .long_name   = NULL_IF_CONFIG_SMALL("Metal Gear Solid: The Twin Snakes"),
     .read_probe  = read_probe,
     .read_header = read_header,
     .read_packet = read_packet,

     .flags       = AVFMT_GENERIC_INDEX,

 };