PeerStreamer

/*

 * NC camera feed demuxer

 * Copyright (c) 2009  Nicolas Martin (martinic at iro dot umontreal dot ca)

 *                     Edouard Auvinet

 *

 * 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

 */

#include "libavutil/intreadwrite.h"

#include "avformat.h"

#define NC_VIDEO_FLAG 0x1A5

static int nc_probe(AVProbeData *probe_packet)

{

    int size;

    if (AV_RB32(probe_packet->buf) != NC_VIDEO_FLAG)

        return 0;

    size = AV_RL16(probe_packet->buf + 5);

    if (size + 20 > probe_packet->buf_size)

        return 3*AVPROBE_SCORE_MAX/2;

    if (AV_RB32(probe_packet->buf+16+size) == NC_VIDEO_FLAG)

        return AVPROBE_SCORE_MAX;

    return 0;

}

static int nc_read_header(AVFormatContext *s, AVFormatParameters *ap)

{

    AVStream *st = av_new_stream(s, 0);

    if (!st)

        return AVERROR(ENOMEM);

    st->codec->codec_type = CODEC_TYPE_VIDEO;

    st->codec->codec_id   = CODEC_ID_MPEG4;

    st->need_parsing      = AVSTREAM_PARSE_FULL;

    av_set_pts_info(st, 64, 1, 100);

    return 0;

}

static int nc_read_packet(AVFormatContext *s, AVPacket *pkt)

{

    int size;

    int ret;

    uint32_t state=-1;

    while (state != NC_VIDEO_FLAG) {

        if (url_feof(s->pb))

            return AVERROR(EIO);

        state = (state<<8) + get_byte(s->pb);

    }

    get_byte(s->pb);

    size = get_le16(s->pb);

    url_fskip(s->pb, 9);

    if (size == 0) {

        av_log(s, AV_LOG_DEBUG, "Next packet size is zero\n");

        return AVERROR(EAGAIN);

    }

    ret = av_get_packet(s->pb, pkt, size);

    if (ret != size) {

        if (ret > 0) av_free_packet(pkt);

        return AVERROR(EIO);

    }

    pkt->stream_index = 0;

    return size;

}

AVInputFormat nc_demuxer = {

    "nc",

    NULL_IF_CONFIG_SMALL("NC camera feed format"),

    0,

    nc_probe,

    nc_read_header,

    nc_read_packet,

    .extensions = "v",

};