aac5773f
 hucm
功能基本完成，接口待打磨
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/*
* 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;
}
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