/*

 * RAW H.264 video demuxer

 * Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at>

 *

 * 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 "libavcodec/get_bits.h"

#include "libavcodec/golomb.h"

#include "avformat.h"

#include "rawdec.h"

#define MAX_SPS_COUNT          32

#define MAX_PPS_COUNT         256

static int h264_probe(const AVProbeData *p)

{

    uint32_t code = -1;

    int sps = 0, pps = 0, idr = 0, res = 0, sli = 0;

    int i, ret;

    int pps_ids[MAX_PPS_COUNT+1] = {0};

    int sps_ids[MAX_SPS_COUNT+1] = {0};

    unsigned pps_id, sps_id;

    GetBitContext gb;

    for (i = 0; i + 2 < p->buf_size; i++) {

        code = (code << 8) + p->buf[i];

        if ((code & 0xffffff00) == 0x100) {

            int ref_idc = (code >> 5) & 3;

            int type    = code & 0x1F;

            static const int8_t ref_zero[] = {

                 2,  0,  0,  0,  0, -1,  1, -1,

                -1,  1,  1,  1,  1, -1,  2,  2,

                 2,  2,  2,  0,  2,  2,  2,  2,

                 2,  2,  2,  2,  2,  2,  2,  2

            };

            if (code & 0x80) // forbidden_bit

                return 0;

            if (ref_zero[type] == 1 && ref_idc)

                return 0;

            if (ref_zero[type] == -1 && !ref_idc)

                return 0;

            if (ref_zero[type] == 2) {

                if (!(code == 0x100 && !p->buf[i + 1] && !p->buf[i + 2]))

                    res++;

            }

            ret = init_get_bits8(&gb, p->buf + i + 1, p->buf_size - i - 1);

            if (ret < 0)

                return 0;

            switch (type) {

            case 1:

            case 5:

                get_ue_golomb_long(&gb);

                if (get_ue_golomb_long(&gb) > 9U)

                    return 0;

                pps_id = get_ue_golomb_long(&gb);

                if (pps_id > MAX_PPS_COUNT)

                    return 0;

                if (!pps_ids[pps_id])

                    break;

                if (type == 1)

                    sli++;

                else

                    idr++;

                break;

            case 7:

                skip_bits(&gb, 14);

                if (get_bits(&gb, 2))

                    return 0;

                skip_bits(&gb, 8);

                sps_id = get_ue_golomb_long(&gb);

                if (sps_id > MAX_SPS_COUNT)

                    return 0;

                sps_ids[sps_id] = 1;

                sps++;

                break;

            case 8:

                pps_id = get_ue_golomb_long(&gb);

                if (pps_id > MAX_PPS_COUNT)

                    return 0;

                sps_id = get_ue_golomb_long(&gb);

                if (sps_id > MAX_SPS_COUNT)

                    return 0;

                if (!sps_ids[sps_id])

                    break;

                pps_ids[pps_id] = 1;

                pps++;

                break;

            }

        }

    }

    ff_tlog(NULL, "sps:%d pps:%d idr:%d sli:%d res:%d\n", sps, pps, idr, sli, res);

    if (sps && pps && (idr || sli > 3) && res < (sps + pps + idr))

        return AVPROBE_SCORE_EXTENSION + 1;  // 1 more than .mpg

    return 0;

}

FF_DEF_RAWVIDEO_DEMUXER(h264, "raw H.264 video", h264_probe, "h26l,h264,264,avc", AV_CODEC_ID_H264)