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/libavformat/oggparseskeleton.c

http://github.com/FFmpeg/FFmpeg
C | 101 lines | 64 code | 13 blank | 24 comment | 20 complexity | e9c3f8746545eac540c1418c04595244 MD5 | raw file
  1/*
  2 * Copyright (C) 2010 David Conrad
  3 *
  4 * This file is part of FFmpeg.
  5 *
  6 * FFmpeg is free software; you can redistribute it and/or
  7 * modify it under the terms of the GNU Lesser General Public
  8 * License as published by the Free Software Foundation; either
  9 * version 2.1 of the License, or (at your option) any later version.
 10 *
 11 * FFmpeg is distributed in the hope that it will be useful,
 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 14 * Lesser General Public License for more details.
 15 *
 16 * You should have received a copy of the GNU Lesser General Public
 17 * License along with FFmpeg; if not, write to the Free Software
 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 19 */
 20
 21#include "libavcodec/bytestream.h"
 22#include "avformat.h"
 23#include "internal.h"
 24#include "oggdec.h"
 25
 26static int skeleton_header(AVFormatContext *s, int idx)
 27{
 28    struct ogg *ogg = s->priv_data;
 29    struct ogg_stream *os = ogg->streams + idx;
 30    AVStream *st = s->streams[idx];
 31    uint8_t *buf = os->buf + os->pstart;
 32    int version_major, version_minor;
 33    int64_t start_num, start_den;
 34    uint64_t start_granule;
 35    int target_idx, start_time;
 36
 37    st->codecpar->codec_type = AVMEDIA_TYPE_DATA;
 38
 39    if ((os->flags & OGG_FLAG_EOS) && os->psize == 0)
 40        return 1;
 41
 42    if (os->psize < 8)
 43        return -1;
 44
 45    if (!strncmp(buf, "fishead", 8)) {
 46        if (os->psize < 64)
 47            return -1;
 48
 49        version_major = AV_RL16(buf+8);
 50        version_minor = AV_RL16(buf+10);
 51
 52        if (version_major != 3 && version_major != 4) {
 53            av_log(s, AV_LOG_WARNING, "Unknown skeleton version %d.%d\n",
 54                   version_major, version_minor);
 55            return -1;
 56        }
 57
 58        // This is the overall start time. We use it for the start time of
 59        // of the skeleton stream since if left unset lavf assumes 0,
 60        // which we don't want since skeleton is timeless
 61        // FIXME: the real meaning of this field is "start playback at
 62        // this time which can be in the middle of a packet
 63        start_num = AV_RL64(buf+12);
 64        start_den = AV_RL64(buf+20);
 65
 66        if (start_den > 0 && start_num > 0) {
 67            int base_den;
 68            av_reduce(&start_time, &base_den, start_num, start_den, INT_MAX);
 69            avpriv_set_pts_info(st, 64, 1, base_den);
 70            os->lastpts =
 71            st->start_time = start_time;
 72        }
 73    } else if (!strncmp(buf, "fisbone", 8)) {
 74        if (os->psize < 52)
 75            return -1;
 76
 77        target_idx = ogg_find_stream(ogg, AV_RL32(buf+12));
 78        start_granule = AV_RL64(buf+36);
 79        if (target_idx < 0) {
 80            av_log(s, AV_LOG_WARNING, "Serial number in fisbone doesn't match any stream\n");
 81            return 1;
 82        }
 83        os = ogg->streams + target_idx;
 84        if (os->start_granule != OGG_NOGRANULE_VALUE) {
 85            av_log(s, AV_LOG_WARNING, "Multiple fisbone for the same stream\n");
 86            return 1;
 87        }
 88        if (start_granule != OGG_NOGRANULE_VALUE) {
 89            os->start_granule = start_granule;
 90        }
 91    }
 92
 93    return 1;
 94}
 95
 96const struct ogg_codec ff_skeleton_codec = {
 97    .magic = "fishead",
 98    .magicsize = 8,
 99    .header = skeleton_header,
100    .nb_header = 0,
101};