libavformat/lvfdec.c
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 /*
  * LVF 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 "avformat.h"
 #include "riff.h"
 
 static int lvf_probe(AVProbeData *p)
 {
     if (AV_RL32(p->buf) == MKTAG('L', 'V', 'F', 'F'))
         return AVPROBE_SCORE_MAX / 2;
     return 0;
 }
 
 static int lvf_read_header(AVFormatContext *s)
 {
     AVStream *st;
     int64_t next_offset;
     unsigned size, nb_streams, id;
 
     avio_skip(s->pb, 16);
     nb_streams = avio_rl32(s->pb);
     if (!nb_streams)
         return AVERROR_INVALIDDATA;
     if (nb_streams > 2) {
         av_log_ask_for_sample(s, "too many streams\n");
         return AVERROR_PATCHWELCOME;
     }
 
     avio_skip(s->pb, 1012);
 
     while (!url_feof(s->pb)) {
         id          = avio_rl32(s->pb);
         size        = avio_rl32(s->pb);
         next_offset = avio_tell(s->pb) + size;
 
         switch (id) {
         case MKTAG('0', '0', 'f', 'm'):
             st = avformat_new_stream(s, 0);
             if (!st)
                 return AVERROR(ENOMEM);
 
             st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
             avio_skip(s->pb, 4);
             st->codec->width      = avio_rl32(s->pb);
             st->codec->height     = avio_rl32(s->pb);
             avio_skip(s->pb, 4);
             st->codec->codec_tag  = avio_rl32(s->pb);
             st->codec->codec_id   = ff_codec_get_id(ff_codec_bmp_tags,
                                                     st->codec->codec_tag);
             avpriv_set_pts_info(st, 32, 1, 1000);
             break;
         case MKTAG('0', '1', 'f', 'm'):
             st = avformat_new_stream(s, 0);
             if (!st)
                 return AVERROR(ENOMEM);
 
             st->codec->codec_type  = AVMEDIA_TYPE_AUDIO;
             st->codec->codec_tag   = avio_rl16(s->pb);
             st->codec->channels    = avio_rl16(s->pb);
             st->codec->sample_rate = avio_rl16(s->pb);
             avio_skip(s->pb, 8);
             st->codec->bits_per_coded_sample = avio_r8(s->pb);
             st->codec->codec_id    = ff_codec_get_id(ff_codec_wav_tags,
                                                      st->codec->codec_tag);
             avpriv_set_pts_info(st, 32, 1, 1000);
             break;
         case 0:
             avio_seek(s->pb, 2048 + 8, SEEK_SET);
             return 0;
         default:
             av_log_ask_for_sample(s, "unknown id\n");
             return AVERROR_PATCHWELCOME;
         }
 
         avio_seek(s->pb, next_offset, SEEK_SET);
     }
 
     return AVERROR_EOF;
 }
 
 static int lvf_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     unsigned size, flags, timestamp, id;
     int64_t pos;
     int ret, is_video = 0;
 
     pos = avio_tell(s->pb);
     while (!url_feof(s->pb)) {
         id    = avio_rl32(s->pb);
         size  = avio_rl32(s->pb);
 
         if (size == 0xFFFFFFFFu)
             return AVERROR_EOF;
 
         switch (id) {
         case MKTAG('0', '0', 'd', 'c'):
             is_video = 1;
         case MKTAG('0', '1', 'w', 'b'):
             if (size < 8)
                 return AVERROR_INVALIDDATA;
             timestamp = avio_rl32(s->pb);
             flags = avio_rl32(s->pb);
             ret = av_get_packet(s->pb, pkt, size - 8);
             if (flags & (1 << 12))
                 pkt->flags |= AV_PKT_FLAG_KEY;
             pkt->stream_index = is_video ? 0 : 1;
             pkt->pts          = timestamp;
             pkt->pos          = pos;
             return ret;
         default:
             ret = avio_skip(s->pb, size);
         }
 
         if (ret < 0)
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             return ret;
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     }
 
     return AVERROR_EOF;
 }
 
 AVInputFormat ff_lvf_demuxer = {
     .name        = "lvf",
     .long_name   = NULL_IF_CONFIG_SMALL("LVF"),
     .read_probe  = lvf_probe,
     .read_header = lvf_read_header,
     .read_packet = lvf_read_packet,
     .extensions  = "lvf",
     .flags       = AVFMT_GENERIC_INDEX,
 };