FFmpeg/libavformat/mj2kdec.c

/*
 * MJPEG 2000 Demuxer
 * Copyright (c) 2016 Ståle Kristoffersen
 *
 * 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"
#include "rawdec.h"

static int mjpeg2000_probe(const AVProbeData *p)
{
    const uint8_t *b = p->buf;
    int i, marker, marker_size;
    int frames = 0, invalid = 0;

    for (i = 0; i < p->buf_size - 5; i++) {
        if (AV_RB32(b) == 0xff4fff51){
            marker_size = AV_RB16(b+4);
            if (marker_size + i < p->buf_size - 4) {
                marker = AV_RB8(b+4+marker_size);
                if (marker == 0xff)
                    frames++;
                else
                    invalid++;
            }
        }
        b += 1;
    }
    if (invalid*4 + 1 < frames) {
        if (invalid == 0 && frames > 2)
            return AVPROBE_SCORE_EXTENSION / 2;
        return AVPROBE_SCORE_EXTENSION / 4;
    }
    return 0;
}
FF_DEF_RAWVIDEO_DEMUXER2(mjpeg_2000, "raw MJPEG 2000 video", mjpeg2000_probe, "j2k", AV_CODEC_ID_JPEG2000, AVFMT_GENERIC_INDEX|AVFMT_NOTIMESTAMPS)