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ffmpeg / libavformat / oggparseskeleton.c @ a351110e

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/*
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 * Copyright (C) 2010 David Conrad
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include "libavcodec/bytestream.h"
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#include "avformat.h"
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#include "oggdec.h"
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static int skeleton_header(AVFormatContext *s, int idx)
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{
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    struct ogg *ogg = s->priv_data;
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    struct ogg_stream *os = ogg->streams + idx;
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    AVStream *st = s->streams[idx];
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    uint8_t *buf = os->buf + os->pstart;
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    int version_major, version_minor;
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    int64_t start_num, start_den, start_granule;
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    int target_idx, start_time;
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    strcpy(st->codec->codec_name, "skeleton");
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    st->codec->codec_type = AVMEDIA_TYPE_DATA;
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    if (os->psize < 8)
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        return -1;
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    if (!strncmp(buf, "fishead", 8)) {
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        if (os->psize < 64)
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            return -1;
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        version_major = AV_RL16(buf+8);
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        version_minor = AV_RL16(buf+10);
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        if (version_major != 3) {
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            av_log(s, AV_LOG_WARNING, "Unknown skeleton version %d.%d\n",
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                   version_major, version_minor);
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            return -1;
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        }
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        // This is the overall start time. We use it for the start time of
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        // of the skeleton stream since if left unset lavf assumes 0,
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        // which we don't want since skeleton is timeless
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        // FIXME: the real meaning of this field is "start playback at
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        // this time which can be in the middle of a packet
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        start_num = AV_RL64(buf+12);
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        start_den = AV_RL64(buf+20);
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        if (start_den) {
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            int64_t base_den;
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            av_reduce(&start_time, &base_den, start_num, start_den, INT_MAX);
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            av_set_pts_info(st, 64, 1, base_den);
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            os->lastpts =
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            st->start_time = start_time;
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        }
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    } else if (!strncmp(buf, "fisbone", 8)) {
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        if (os->psize < 52)
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            return -1;
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        target_idx = ogg_find_stream(ogg, AV_RL32(buf+12));
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        start_granule = AV_RL64(buf+36);
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        if (target_idx >= 0 && start_granule != -1) {
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            ogg->streams[target_idx].lastpts =
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            s->streams[target_idx]->start_time = ogg_gptopts(s, target_idx, start_granule, NULL);
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        }
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    }
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    return 1;
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}
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const struct ogg_codec ff_skeleton_codec = {
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    .magic = "fishead",
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    .magicsize = 8,
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    .header = skeleton_header,
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};