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ffmpeg / libavformat / filmstripdec.c @ e356fc57

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1 83ab7f18 Peter Ross
/*
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 * Adobe Filmstrip demuxer
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 * Copyright (c) 2010 Peter Ross
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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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/**
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 * @file
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 * Adobe Filmstrip demuxer
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 */
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#include "libavutil/intreadwrite.h"
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#include "avformat.h"
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#define RAND_TAG MKBETAG('R','a','n','d')
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typedef struct {
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    int leading;
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} FilmstripDemuxContext;
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static int read_header(AVFormatContext *s,
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                       AVFormatParameters *ap)
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{
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    FilmstripDemuxContext *film = s->priv_data;
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    AVIOContext *pb = s->pb;
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    AVStream *st;
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    if (url_is_streamed(s->pb))
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        return AVERROR(EIO);
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    avio_seek(pb, url_fsize(pb) - 36, SEEK_SET);
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    if (avio_rb32(pb) != RAND_TAG) {
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        av_log(s, AV_LOG_ERROR, "magic number not found");
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        return AVERROR_INVALIDDATA;
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    }
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    st = av_new_stream(s, 0);
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    if (!st)
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        return AVERROR(ENOMEM);
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    st->nb_frames = avio_rb32(pb);
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    if (avio_rb16(pb) != 0) {
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        av_log_ask_for_sample(s, "unsupported packing method\n");
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        return AVERROR_INVALIDDATA;
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    }
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    avio_seek(pb, 2, SEEK_CUR);
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    st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
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    st->codec->codec_id   = CODEC_ID_RAWVIDEO;
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    st->codec->pix_fmt    = PIX_FMT_RGBA;
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    st->codec->codec_tag  = 0; /* no fourcc */
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    st->codec->width      = avio_rb16(pb);
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    st->codec->height     = avio_rb16(pb);
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    film->leading         = avio_rb16(pb);
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    av_set_pts_info(st, 64, 1, avio_rb16(pb));
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    avio_seek(pb, 0, SEEK_SET);
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    return 0;
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}
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static int read_packet(AVFormatContext *s,
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                       AVPacket *pkt)
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{
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    FilmstripDemuxContext *film = s->priv_data;
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    AVStream *st = s->streams[0];
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    if (url_feof(s->pb))
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        return AVERROR(EIO);
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    pkt->dts = url_ftell(s->pb) / (st->codec->width * (st->codec->height + film->leading) * 4);
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    pkt->size = av_get_packet(s->pb, pkt, st->codec->width * st->codec->height * 4);
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    avio_seek(s->pb, st->codec->width * film->leading * 4, SEEK_CUR);
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    if (pkt->size < 0)
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        return pkt->size;
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    pkt->flags |= AV_PKT_FLAG_KEY;
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    return 0;
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}
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static int read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
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{
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    AVStream *st = s->streams[stream_index];
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    avio_seek(s->pb, FFMAX(timestamp, 0) * st->codec->width * st->codec->height * 4, SEEK_SET);
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    return 0;
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}
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AVInputFormat ff_filmstrip_demuxer = {
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    "filmstrip",
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    NULL_IF_CONFIG_SMALL("Adobe Filmstrip"),
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    sizeof(FilmstripDemuxContext),
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    NULL,
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    read_header,
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    read_packet,
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    NULL,
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    read_seek,
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    .extensions = "flm",
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};