ffmpeg/libavformat/filmstripdec.c

112 lines
3.1 KiB
C

/*
* Adobe Filmstrip demuxer
* Copyright (c) 2010 Peter Ross
*
* 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
*/
/**
* @file
* Adobe Filmstrip demuxer
*/
#include "libavutil/intreadwrite.h"
#include "avformat.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;
ByteIOContext *pb = s->pb;
AVStream *st;
if (url_is_streamed(s->pb))
return AVERROR(EIO);
url_fseek(pb, url_fsize(pb) - 36, SEEK_SET);
if (get_be32(pb) != RAND_TAG) {
av_log(s, AV_LOG_ERROR, "magic number not found");
return AVERROR_INVALIDDATA;
}
st = av_new_stream(s, 0);
if (!st)
return AVERROR(ENOMEM);
st->nb_frames = get_be32(pb);
if (get_be16(pb) != 0) {
av_log_ask_for_sample(s, "unsupported packing method\n");
return AVERROR_INVALIDDATA;
}
url_fskip(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 = get_be16(pb);
st->codec->height = get_be16(pb);
film->leading = get_be16(pb);
av_set_pts_info(st, 64, 1, get_be16(pb));
url_fseek(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 (url_feof(s->pb))
return AVERROR(EIO);
pkt->dts = url_ftell(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);
url_fskip(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];
url_fseek(s->pb, FFMAX(timestamp, 0) * st->codec->width * st->codec->height * 4, SEEK_SET);
return 0;
}
AVInputFormat ff_filmstrip_demuxer = {
"filmstrip",
NULL_IF_CONFIG_SMALL("Adobe Filmstrip"),
sizeof(FilmstripDemuxContext),
NULL,
read_header,
read_packet,
NULL,
read_seek,
.extensions = "flm",
};