/*

 * Canopus common routines

 * Copyright (c) 2015 Vittorio Giovara <vittorio.giovara@gmail.com>

 *

 * 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 <stdint.h>

#include "libavutil/rational.h"

#include "avcodec.h"

#include "bytestream.h"

#include "canopus.h"

int ff_canopus_parse_info_tag(AVCodecContext *avctx,

                              const uint8_t *src, size_t size)

{

    GetByteContext gbc;

    int par_x, par_y, field_order;

    bytestream2_init(&gbc, src, size);

    /* Parse aspect ratio. */

    bytestream2_skip(&gbc, 8); // unknown, 16 bits 1

    par_x = bytestream2_get_le32(&gbc);

    par_y = bytestream2_get_le32(&gbc);

    if (par_x && par_y)

        av_reduce(&avctx->sample_aspect_ratio.num,

                  &avctx->sample_aspect_ratio.den,

                  par_x, par_y, 255);

    /* Short INFO tag (used in CLLC) has only AR data. */

    if (size == 0x18)

        return 0;

    bytestream2_skip(&gbc, 16); // unknown RDRT tag

    /* Parse FIEL tag. */

    bytestream2_skip(&gbc, 8); // 'FIEL' and 4 bytes 0

    field_order = bytestream2_get_le32(&gbc);

    switch (field_order) {

    case 0: avctx->field_order = AV_FIELD_TT; break;

    case 1: avctx->field_order = AV_FIELD_BB; break;

    case 2: avctx->field_order = AV_FIELD_PROGRESSIVE; break;

    }

    return 0;

}