PeerStreamer

/*

 * 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;

    AVIOContext *pb = s->pb;

    AVStream *st;

    if (url_is_streamed(s->pb))

        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 = av_new_stream(s, 0);

    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);

    av_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 = {

    "filmstrip",

    NULL_IF_CONFIG_SMALL("Adobe Filmstrip"),

    sizeof(FilmstripDemuxContext),

    NULL,

    read_header,

    read_packet,

    NULL,

    read_seek,

    .extensions = "flm",

};