ffmpeg/libavformat/filmstripdec.c

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/*
* Adobe Filmstrip demuxer
* Copyright (c) 2010 Peter Ross
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* Adobe Filmstrip demuxer
*/
#include "libavutil/intreadwrite.h"
#include "avformat.h"
#include "internal.h"
#define RAND_TAG MKBETAG('R','a','n','d')
typedef struct {
int leading;
} FilmstripDemuxContext;
static int read_header(AVFormatContext *s,
AVFormatParameters *ap)
{
FilmstripDemuxContext *film = s->priv_data;
AVIOContext *pb = s->pb;
AVStream *st;
if (!s->pb->seekable)
return AVERROR(EIO);
avio_seek(pb, avio_size(pb) - 36, SEEK_SET);
if (avio_rb32(pb) != RAND_TAG) {
av_log(s, AV_LOG_ERROR, "magic number not found");
return AVERROR_INVALIDDATA;
}
st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
st->nb_frames = avio_rb32(pb);
if (avio_rb16(pb) != 0) {
av_log_ask_for_sample(s, "unsupported packing method\n");
return AVERROR_INVALIDDATA;
}
avio_skip(pb, 2);
st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
st->codec->codec_id = CODEC_ID_RAWVIDEO;
st->codec->pix_fmt = PIX_FMT_RGBA;
st->codec->codec_tag = 0; /* no fourcc */
st->codec->width = avio_rb16(pb);
st->codec->height = avio_rb16(pb);
film->leading = avio_rb16(pb);
avpriv_set_pts_info(st, 64, 1, avio_rb16(pb));
avio_seek(pb, 0, SEEK_SET);
return 0;
}
static int read_packet(AVFormatContext *s,
AVPacket *pkt)
{
FilmstripDemuxContext *film = s->priv_data;
AVStream *st = s->streams[0];
if (s->pb->eof_reached)
return AVERROR(EIO);
pkt->dts = avio_tell(s->pb) / (st->codec->width * (st->codec->height + film->leading) * 4);
pkt->size = av_get_packet(s->pb, pkt, st->codec->width * st->codec->height * 4);
avio_skip(s->pb, st->codec->width * film->leading * 4);
if (pkt->size < 0)
return pkt->size;
pkt->flags |= AV_PKT_FLAG_KEY;
return 0;
}
static int read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
{
AVStream *st = s->streams[stream_index];
avio_seek(s->pb, FFMAX(timestamp, 0) * st->codec->width * st->codec->height * 4, SEEK_SET);
return 0;
}
AVInputFormat ff_filmstrip_demuxer = {
.name = "filmstrip",
.long_name = NULL_IF_CONFIG_SMALL("Adobe Filmstrip"),
.priv_data_size = sizeof(FilmstripDemuxContext),
.read_header = read_header,
.read_packet = read_packet,
.read_seek = read_seek,
.extensions = "flm",
};