FFmpeg
libavcodec
canopus.c
Go to the documentation of this file.
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/*
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* Canopus common routines
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* Copyright (c) 2015 Vittorio Giovara <vittorio.giovara@gmail.com>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <stdint.h>
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#include "
libavutil/rational.h
"
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#include "
avcodec.h
"
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#include "
bytestream.h
"
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#include "
canopus.h
"
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int
ff_canopus_parse_info_tag
(
AVCodecContext
*avctx,
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const
uint8_t *
src
,
size_t
size
)
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{
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GetByteContext
gbc;
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int
par_x, par_y, field_order;
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bytestream2_init
(&gbc,
src
,
size
);
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/* Parse aspect ratio. */
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bytestream2_skip
(&gbc, 8);
// unknown, 16 bits 1
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par_x = bytestream2_get_le32(&gbc);
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par_y = bytestream2_get_le32(&gbc);
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if
(par_x && par_y)
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av_reduce
(&avctx->
sample_aspect_ratio
.
num
,
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&avctx->
sample_aspect_ratio
.
den
,
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par_x, par_y, 255);
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/* Short INFO tag (used in CLLC) has only AR data. */
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if
(
size
== 0x18)
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return
0;
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bytestream2_skip
(&gbc, 16);
// unknown RDRT tag
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/* Parse FIEL tag. */
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bytestream2_skip
(&gbc, 8);
// 'FIEL' and 4 bytes 0
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field_order = bytestream2_get_le32(&gbc);
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switch
(field_order) {
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case
0: avctx->
field_order
=
AV_FIELD_TT
;
break
;
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case
1: avctx->
field_order
=
AV_FIELD_BB
;
break
;
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case
2: avctx->
field_order
=
AV_FIELD_PROGRESSIVE
;
break
;
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}
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return
0;
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}
GetByteContext
Definition:
bytestream.h:33
AV_FIELD_PROGRESSIVE
@ AV_FIELD_PROGRESSIVE
Definition:
defs.h:202
rational.h
AVCodecContext::field_order
enum AVFieldOrder field_order
Field order.
Definition:
avcodec.h:714
bytestream2_skip
static av_always_inline void bytestream2_skip(GetByteContext *g, unsigned int size)
Definition:
bytestream.h:168
AV_FIELD_TT
@ AV_FIELD_TT
Top coded_first, top displayed first.
Definition:
defs.h:203
ff_canopus_parse_info_tag
int ff_canopus_parse_info_tag(AVCodecContext *avctx, const uint8_t *src, size_t size)
Definition:
canopus.c:30
av_reduce
int av_reduce(int *dst_num, int *dst_den, int64_t num, int64_t den, int64_t max)
Reduce a fraction.
Definition:
rational.c:35
AVRational::num
int num
Numerator.
Definition:
rational.h:59
canopus.h
size
int size
Definition:
twinvq_data.h:10344
AV_FIELD_BB
@ AV_FIELD_BB
Bottom coded first, bottom displayed first.
Definition:
defs.h:204
avcodec.h
AVCodecContext
main external API structure.
Definition:
avcodec.h:451
AVRational::den
int den
Denominator.
Definition:
rational.h:60
bytestream.h
bytestream2_init
static av_always_inline void bytestream2_init(GetByteContext *g, const uint8_t *buf, int buf_size)
Definition:
bytestream.h:137
AVCodecContext::sample_aspect_ratio
AVRational sample_aspect_ratio
sample aspect ratio (0 if unknown) That is the width of a pixel divided by the height of the pixel.
Definition:
avcodec.h:648
src
#define src
Definition:
vp8dsp.c:248
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