mirror of https://git.videolan.org/git/ffmpeg.git
avutil/{color_utils, csp}: merge color_utils into csp and expose API
libavutil/color_utils contains some avpriv_ symbols that map
enum AVTransferCharacteristic values to gamma-curve approximations and
to the actual transfer functions to invert them (i.e. -> linear).
There's two issues with this:
(1) avpriv is evil and should be avoided whenever possible
(2) libavutil/csp.h exposes a public API for handling color that
already handles primaries and matricies
I don't see any reason this API has to be private, so this commit takes
the functionality from avutil/color_utils and merges it into avutil/csp
with an exposed av_ API rather than the previous avpriv_ API.
Every reference to the previous API has been updated to point to the
new one. color_utils.h has been deleted as well. This should not break
any applications as it only contained avpriv_ symbols in the first
place, so nothing in that header could be referenced by other
applications.
Signed-off-by: Leo Izen <leo.izen@gmail.com>
Signed-off-by: Anton Khirnov <anton@khirnov.net>
This commit is contained in:
Leo Izen
Anton Khirnov
parent
dc1b8135e0
commit
719a93f4e4
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@ -14,6 +14,10 @@ libavutil: 2021-04-27
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API changes, most recent first:
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2023-02-xx - xxxxxxxxxx - lavu 58.0.100 - csp.h
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Add av_csp_approximate_trc_gamma() and av_csp_trc_func_from_id().
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Add av_csp_trc_function.
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2023-02-xx - xxxxxxxxxx - lavc 60.0.100 - avcodec.h
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avcodec_decode_subtitle2() now accepts const AVPacket*.
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@ -36,11 +36,11 @@
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#include "libavutil/avassert.h"
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#include "libavutil/common.h"
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#include "libavutil/csp.h"
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#include "libavutil/imgutils.h"
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#include "libavutil/intfloat.h"
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#include "libavutil/avstring.h"
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#include "libavutil/opt.h"
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#include "libavutil/color_utils.h"
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#include "libavutil/half2float.h"
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#include "avcodec.h"
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@ -1189,7 +1189,7 @@ static int decode_block(AVCodecContext *avctx, void *tdata,
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int i, x, buf_size = s->buf_size;
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int c, rgb_channel_count;
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float one_gamma = 1.0f / s->gamma;
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avpriv_trc_function trc_func = avpriv_get_trc_function_from_trc(s->apply_trc_type);
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av_csp_trc_function trc_func = av_csp_trc_func_from_id(s->apply_trc_type);
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int ret;
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line_offset = AV_RL64(s->gb.buffer + jobnr * 8);
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@ -2215,7 +2215,7 @@ static av_cold int decode_init(AVCodecContext *avctx)
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uint32_t i;
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union av_intfloat32 t;
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float one_gamma = 1.0f / s->gamma;
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avpriv_trc_function trc_func = NULL;
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av_csp_trc_function trc_func = NULL;
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ff_init_half2float_tables(&s->h2f_tables);
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@ -2227,7 +2227,7 @@ static av_cold int decode_init(AVCodecContext *avctx)
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ff_bswapdsp_init(&s->bbdsp);
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#endif
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trc_func = avpriv_get_trc_function_from_trc(s->apply_trc_type);
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trc_func = av_csp_trc_func_from_id(s->apply_trc_type);
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if (trc_func) {
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for (i = 0; i < 65536; ++i) {
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t.i = half2float(i, &s->h2f_tables);
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@ -17,7 +17,6 @@
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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 "libavutil/color_utils.h"
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#include "libavutil/csp.h"
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#include "fflcms2.h"
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@ -29,7 +29,6 @@
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#include "zlib_wrapper.h"
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#include "libavutil/avassert.h"
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#include "libavutil/color_utils.h"
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#include "libavutil/crc.h"
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#include "libavutil/csp.h"
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#include "libavutil/libm.h"
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@ -317,7 +316,7 @@ static int png_get_chrm(enum AVColorPrimaries prim, uint8_t *buf)
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static int png_get_gama(enum AVColorTransferCharacteristic trc, uint8_t *buf)
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{
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double gamma = avpriv_get_gamma_from_trc(trc);
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double gamma = av_csp_approximate_trc_gamma(trc);
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if (gamma <= 1e-6)
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return 0;
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@ -47,6 +47,7 @@
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#include "internal.h"
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#include "libavutil/avstring.h"
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#include "libavutil/channel_layout.h"
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#include "libavutil/csp.h"
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#include "libavutil/intfloat.h"
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#include "libavutil/mathematics.h"
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#include "libavutil/libm.h"
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@ -56,7 +57,6 @@
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#include "libavutil/stereo3d.h"
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#include "libavutil/timecode.h"
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#include "libavutil/dovi_meta.h"
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#include "libavutil/color_utils.h"
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#include "libavutil/uuid.h"
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#include "hevc.h"
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#include "rtpenc.h"
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@ -2011,9 +2011,8 @@ static int mov_write_pasp_tag(AVIOContext *pb, MOVTrack *track)
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static int mov_write_gama_tag(AVFormatContext *s, AVIOContext *pb, MOVTrack *track, double gamma)
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{
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uint32_t gama = 0;
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if (gamma <= 0.0) {
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gamma = avpriv_get_gamma_from_trc(track->par->color_trc);
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}
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if (gamma <= 0.0)
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gamma = av_csp_approximate_trc_gamma(track->par->color_trc);
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av_log(s, AV_LOG_DEBUG, "gamma value %g\n", gamma);
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if (gamma > 1e-6) {
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@ -114,7 +114,6 @@ OBJS = adler32.o \
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cast5.o \
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camellia.o \
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channel_layout.o \
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color_utils.o \
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cpu.o \
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crc.o \
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csp.o \
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@ -1,234 +0,0 @@
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/*
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* Copyright (c) 2015 Kevin Wheatley <kevin.j.wheatley@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 <stddef.h>
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#include <math.h>
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#include "libavutil/color_utils.h"
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#include "libavutil/pixfmt.h"
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double avpriv_get_gamma_from_trc(enum AVColorTransferCharacteristic trc)
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{
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double gamma;
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switch (trc) {
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case AVCOL_TRC_BT709:
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case AVCOL_TRC_SMPTE170M:
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case AVCOL_TRC_SMPTE240M:
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case AVCOL_TRC_BT1361_ECG:
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case AVCOL_TRC_BT2020_10:
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case AVCOL_TRC_BT2020_12:
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/* these share a segmented TRC, but gamma 1.961 is a close
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approximation, and also more correct for decoding content */
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gamma = 1.961;
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break;
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case AVCOL_TRC_GAMMA22:
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case AVCOL_TRC_IEC61966_2_1:
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gamma = 2.2;
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break;
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case AVCOL_TRC_GAMMA28:
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gamma = 2.8;
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break;
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case AVCOL_TRC_LINEAR:
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gamma = 1.0;
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break;
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default:
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gamma = 0.0; // Unknown value representation
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}
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return gamma;
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}
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#define BT709_alpha 1.099296826809442
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#define BT709_beta 0.018053968510807
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static double avpriv_trc_bt709(double Lc)
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{
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const double a = BT709_alpha;
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const double b = BT709_beta;
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return (0.0 > Lc) ? 0.0
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: ( b > Lc) ? 4.500 * Lc
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: a * pow(Lc, 0.45) - (a - 1.0);
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}
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static double avpriv_trc_gamma22(double Lc)
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{
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return (0.0 > Lc) ? 0.0 : pow(Lc, 1.0/ 2.2);
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}
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static double avpriv_trc_gamma28(double Lc)
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{
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return (0.0 > Lc) ? 0.0 : pow(Lc, 1.0/ 2.8);
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}
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static double avpriv_trc_smpte240M(double Lc)
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{
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const double a = 1.1115;
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const double b = 0.0228;
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return (0.0 > Lc) ? 0.0
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: ( b > Lc) ? 4.000 * Lc
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: a * pow(Lc, 0.45) - (a - 1.0);
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}
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static double avpriv_trc_linear(double Lc)
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{
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return Lc;
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}
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static double avpriv_trc_log(double Lc)
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{
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return (0.01 > Lc) ? 0.0 : 1.0 + log10(Lc) / 2.0;
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}
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static double avpriv_trc_log_sqrt(double Lc)
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{
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// sqrt(10) / 1000
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return (0.00316227766 > Lc) ? 0.0 : 1.0 + log10(Lc) / 2.5;
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}
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static double avpriv_trc_iec61966_2_4(double Lc)
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{
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const double a = BT709_alpha;
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const double b = BT709_beta;
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return (-b >= Lc) ? -a * pow(-Lc, 0.45) + (a - 1.0)
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: ( b > Lc) ? 4.500 * Lc
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: a * pow( Lc, 0.45) - (a - 1.0);
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}
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static double avpriv_trc_bt1361(double Lc)
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{
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const double a = BT709_alpha;
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const double b = BT709_beta;
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return (-0.0045 >= Lc) ? -(a * pow(-4.0 * Lc, 0.45) + (a - 1.0)) / 4.0
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: ( b > Lc) ? 4.500 * Lc
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: a * pow( Lc, 0.45) - (a - 1.0);
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}
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static double avpriv_trc_iec61966_2_1(double Lc)
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{
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const double a = 1.055;
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const double b = 0.0031308;
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return (0.0 > Lc) ? 0.0
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: ( b > Lc) ? 12.92 * Lc
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: a * pow(Lc, 1.0 / 2.4) - (a - 1.0);
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}
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static double avpriv_trc_smpte_st2084(double Lc)
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{
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const double c1 = 3424.0 / 4096.0; // c3-c2 + 1
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const double c2 = 32.0 * 2413.0 / 4096.0;
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const double c3 = 32.0 * 2392.0 / 4096.0;
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const double m = 128.0 * 2523.0 / 4096.0;
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const double n = 0.25 * 2610.0 / 4096.0;
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const double L = Lc / 10000.0;
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const double Ln = pow(L, n);
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return (0.0 > Lc) ? 0.0
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: pow((c1 + c2 * Ln) / (1.0 + c3 * Ln), m);
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}
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static double avpriv_trc_smpte_st428_1(double Lc)
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{
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return (0.0 > Lc) ? 0.0
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: pow(48.0 * Lc / 52.37, 1.0 / 2.6);
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}
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static double avpriv_trc_arib_std_b67(double Lc) {
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// The function uses the definition from HEVC, which assumes that the peak
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// white is input level = 1. (this is equivalent to scaling E = Lc * 12 and
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// using the definition from the ARIB STD-B67 spec)
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const double a = 0.17883277;
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const double b = 0.28466892;
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const double c = 0.55991073;
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return (0.0 > Lc) ? 0.0 :
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(Lc <= 1.0 / 12.0 ? sqrt(3.0 * Lc) : a * log(12.0 * Lc - b) + c);
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}
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avpriv_trc_function avpriv_get_trc_function_from_trc(enum AVColorTransferCharacteristic trc)
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{
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avpriv_trc_function func = NULL;
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switch (trc) {
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case AVCOL_TRC_BT709:
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case AVCOL_TRC_SMPTE170M:
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case AVCOL_TRC_BT2020_10:
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case AVCOL_TRC_BT2020_12:
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func = avpriv_trc_bt709;
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break;
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case AVCOL_TRC_GAMMA22:
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func = avpriv_trc_gamma22;
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break;
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case AVCOL_TRC_GAMMA28:
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func = avpriv_trc_gamma28;
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break;
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case AVCOL_TRC_SMPTE240M:
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func = avpriv_trc_smpte240M;
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break;
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case AVCOL_TRC_LINEAR:
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func = avpriv_trc_linear;
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break;
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case AVCOL_TRC_LOG:
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func = avpriv_trc_log;
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break;
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case AVCOL_TRC_LOG_SQRT:
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func = avpriv_trc_log_sqrt;
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break;
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case AVCOL_TRC_IEC61966_2_4:
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func = avpriv_trc_iec61966_2_4;
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break;
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case AVCOL_TRC_BT1361_ECG:
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func = avpriv_trc_bt1361;
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break;
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case AVCOL_TRC_IEC61966_2_1:
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func = avpriv_trc_iec61966_2_1;
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break;
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case AVCOL_TRC_SMPTEST2084:
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func = avpriv_trc_smpte_st2084;
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break;
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case AVCOL_TRC_SMPTEST428_1:
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func = avpriv_trc_smpte_st428_1;
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break;
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case AVCOL_TRC_ARIB_STD_B67:
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func = avpriv_trc_arib_std_b67;
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break;
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case AVCOL_TRC_RESERVED0:
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case AVCOL_TRC_UNSPECIFIED:
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case AVCOL_TRC_RESERVED:
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default:
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break;
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}
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return func;
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}
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@ -1,56 +0,0 @@
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/*
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* Copyright (c) 2015 Kevin Wheatley <kevin.j.wheatley@gmail.com>
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*
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* 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
|
||||
*/
|
||||
|
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#ifndef AVUTIL_COLOR_UTILS_H
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#define AVUTIL_COLOR_UTILS_H
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#include "libavutil/pixfmt.h"
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|
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/**
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* Determine a suitable 'gamma' value to match the supplied
|
||||
* AVColorTransferCharacteristic.
|
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*
|
||||
* See Apple Technical Note TN2257 (https://developer.apple.com/library/mac/technotes/tn2257/_index.html)
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||||
*
|
||||
* @return Will return an approximation to the simple gamma function matching
|
||||
* the supplied Transfer Characteristic, Will return 0.0 for any
|
||||
* we cannot reasonably match against.
|
||||
*/
|
||||
double avpriv_get_gamma_from_trc(enum AVColorTransferCharacteristic trc);
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||||
|
||||
|
||||
typedef double (*avpriv_trc_function)(double);
|
||||
|
||||
/**
|
||||
* Determine the function needed to apply the given
|
||||
* AVColorTransferCharacteristic to linear input.
|
||||
*
|
||||
* The function returned should expect a nominal domain and range of [0.0-1.0]
|
||||
* values outside of this range maybe valid depending on the chosen
|
||||
* characteristic function.
|
||||
*
|
||||
* @return Will return pointer to the function matching the
|
||||
* supplied Transfer Characteristic. If unspecified will
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||||
* return NULL:
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||||
*/
|
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avpriv_trc_function avpriv_get_trc_function_from_trc(enum AVColorTransferCharacteristic trc);
|
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|
||||
#endif
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172
libavutil/csp.c
172
libavutil/csp.c
|
|
@ -1,5 +1,8 @@
|
|||
/*
|
||||
* Copyright (c) 2015 Kevin Wheatley <kevin.j.wheatley@gmail.com>
|
||||
* Copyright (c) 2016 Ronald S. Bultje <rsbultje@gmail.com>
|
||||
* Copyright (c) 2023 Leo Izen <leo.izen@gmail.com>
|
||||
*
|
||||
* This file is part of FFmpeg.
|
||||
*
|
||||
* FFmpeg is free software; you can redistribute it and/or
|
||||
|
|
@ -21,9 +24,11 @@
|
|||
* @file Colorspace functions for libavutil
|
||||
* @author Ronald S. Bultje <rsbultje@gmail.com>
|
||||
* @author Leo Izen <leo.izen@gmail.com>
|
||||
* @author Kevin Wheatley <kevin.j.wheatley@gmail.com>
|
||||
*/
|
||||
|
||||
#include <stdlib.h>
|
||||
#include <math.h>
|
||||
|
||||
#include "attributes.h"
|
||||
#include "csp.h"
|
||||
|
|
@ -126,3 +131,170 @@ enum AVColorPrimaries av_csp_primaries_id_from_desc(const AVColorPrimariesDesc *
|
|||
|
||||
return AVCOL_PRI_UNSPECIFIED;
|
||||
}
|
||||
|
||||
static const double approximate_gamma[AVCOL_TRC_NB] = {
|
||||
[AVCOL_TRC_BT709] = 1.961,
|
||||
[AVCOL_TRC_SMPTE170M] = 1.961,
|
||||
[AVCOL_TRC_SMPTE240M] = 1.961,
|
||||
[AVCOL_TRC_BT1361_ECG] = 1.961,
|
||||
[AVCOL_TRC_BT2020_10] = 1.961,
|
||||
[AVCOL_TRC_BT2020_12] = 1.961,
|
||||
[AVCOL_TRC_GAMMA22] = 2.2,
|
||||
[AVCOL_TRC_IEC61966_2_1] = 2.2,
|
||||
[AVCOL_TRC_GAMMA28] = 2.8,
|
||||
[AVCOL_TRC_LINEAR] = 1.0,
|
||||
[AVCOL_TRC_SMPTE428] = 2.6,
|
||||
};
|
||||
|
||||
double av_csp_approximate_trc_gamma(enum AVColorTransferCharacteristic trc)
|
||||
{
|
||||
double gamma;
|
||||
if (trc >= AVCOL_TRC_NB)
|
||||
return 0.0;
|
||||
gamma = approximate_gamma[trc];
|
||||
if (gamma > 0)
|
||||
return gamma;
|
||||
return 0.0;
|
||||
}
|
||||
|
||||
#define BT709_alpha 1.099296826809442
|
||||
#define BT709_beta 0.018053968510807
|
||||
|
||||
static double trc_bt709(double Lc)
|
||||
{
|
||||
const double a = BT709_alpha;
|
||||
const double b = BT709_beta;
|
||||
|
||||
return (0.0 > Lc) ? 0.0
|
||||
: ( b > Lc) ? 4.500 * Lc
|
||||
: a * pow(Lc, 0.45) - (a - 1.0);
|
||||
}
|
||||
|
||||
static double trc_gamma22(double Lc)
|
||||
{
|
||||
return (0.0 > Lc) ? 0.0 : pow(Lc, 1.0/ 2.2);
|
||||
}
|
||||
|
||||
static double trc_gamma28(double Lc)
|
||||
{
|
||||
return (0.0 > Lc) ? 0.0 : pow(Lc, 1.0/ 2.8);
|
||||
}
|
||||
|
||||
static double trc_smpte240M(double Lc)
|
||||
{
|
||||
const double a = 1.1115;
|
||||
const double b = 0.0228;
|
||||
|
||||
return (0.0 > Lc) ? 0.0
|
||||
: ( b > Lc) ? 4.000 * Lc
|
||||
: a * pow(Lc, 0.45) - (a - 1.0);
|
||||
}
|
||||
|
||||
static double trc_linear(double Lc)
|
||||
{
|
||||
return Lc;
|
||||
}
|
||||
|
||||
static double trc_log(double Lc)
|
||||
{
|
||||
return (0.01 > Lc) ? 0.0 : 1.0 + log10(Lc) / 2.0;
|
||||
}
|
||||
|
||||
static double trc_log_sqrt(double Lc)
|
||||
{
|
||||
// sqrt(10) / 1000
|
||||
return (0.00316227766 > Lc) ? 0.0 : 1.0 + log10(Lc) / 2.5;
|
||||
}
|
||||
|
||||
static double trc_iec61966_2_4(double Lc)
|
||||
{
|
||||
const double a = BT709_alpha;
|
||||
const double b = BT709_beta;
|
||||
|
||||
return (-b >= Lc) ? -a * pow(-Lc, 0.45) + (a - 1.0)
|
||||
: ( b > Lc) ? 4.500 * Lc
|
||||
: a * pow( Lc, 0.45) - (a - 1.0);
|
||||
}
|
||||
|
||||
static double trc_bt1361(double Lc)
|
||||
{
|
||||
const double a = BT709_alpha;
|
||||
const double b = BT709_beta;
|
||||
|
||||
return (-0.0045 >= Lc) ? -(a * pow(-4.0 * Lc, 0.45) + (a - 1.0)) / 4.0
|
||||
: ( b > Lc) ? 4.500 * Lc
|
||||
: a * pow( Lc, 0.45) - (a - 1.0);
|
||||
}
|
||||
|
||||
static double trc_iec61966_2_1(double Lc)
|
||||
{
|
||||
const double a = 1.055;
|
||||
const double b = 0.0031308;
|
||||
|
||||
return (0.0 > Lc) ? 0.0
|
||||
: ( b > Lc) ? 12.92 * Lc
|
||||
: a * pow(Lc, 1.0 / 2.4) - (a - 1.0);
|
||||
}
|
||||
|
||||
static double trc_smpte_st2084(double Lc)
|
||||
{
|
||||
const double c1 = 3424.0 / 4096.0; // c3-c2 + 1
|
||||
const double c2 = 32.0 * 2413.0 / 4096.0;
|
||||
const double c3 = 32.0 * 2392.0 / 4096.0;
|
||||
const double m = 128.0 * 2523.0 / 4096.0;
|
||||
const double n = 0.25 * 2610.0 / 4096.0;
|
||||
const double L = Lc / 10000.0;
|
||||
const double Ln = pow(L, n);
|
||||
|
||||
return (0.0 > Lc) ? 0.0
|
||||
: pow((c1 + c2 * Ln) / (1.0 + c3 * Ln), m);
|
||||
|
||||
}
|
||||
|
||||
static double trc_smpte_st428_1(double Lc)
|
||||
{
|
||||
return (0.0 > Lc) ? 0.0
|
||||
: pow(48.0 * Lc / 52.37, 1.0 / 2.6);
|
||||
}
|
||||
|
||||
|
||||
static double trc_arib_std_b67(double Lc) {
|
||||
// The function uses the definition from HEVC, which assumes that the peak
|
||||
// white is input level = 1. (this is equivalent to scaling E = Lc * 12 and
|
||||
// using the definition from the ARIB STD-B67 spec)
|
||||
const double a = 0.17883277;
|
||||
const double b = 0.28466892;
|
||||
const double c = 0.55991073;
|
||||
return (0.0 > Lc) ? 0.0 :
|
||||
(Lc <= 1.0 / 12.0 ? sqrt(3.0 * Lc) : a * log(12.0 * Lc - b) + c);
|
||||
}
|
||||
|
||||
static const av_csp_trc_function trc_funcs[AVCOL_TRC_NB] = {
|
||||
[AVCOL_TRC_BT709] = trc_bt709,
|
||||
[AVCOL_TRC_GAMMA22] = trc_gamma22,
|
||||
[AVCOL_TRC_GAMMA28] = trc_gamma28,
|
||||
[AVCOL_TRC_SMPTE170M] = trc_bt709,
|
||||
[AVCOL_TRC_SMPTE240M] = trc_smpte240M,
|
||||
[AVCOL_TRC_LINEAR] = trc_linear,
|
||||
[AVCOL_TRC_LOG] = trc_log,
|
||||
[AVCOL_TRC_LOG_SQRT] = trc_log_sqrt,
|
||||
[AVCOL_TRC_IEC61966_2_4] = trc_iec61966_2_4,
|
||||
[AVCOL_TRC_BT1361_ECG] = trc_bt1361,
|
||||
[AVCOL_TRC_IEC61966_2_1] = trc_iec61966_2_1,
|
||||
[AVCOL_TRC_BT2020_10] = trc_bt709,
|
||||
[AVCOL_TRC_BT2020_12] = trc_bt709,
|
||||
[AVCOL_TRC_SMPTE2084] = trc_smpte_st2084,
|
||||
[AVCOL_TRC_SMPTE428] = trc_smpte_st428_1,
|
||||
[AVCOL_TRC_ARIB_STD_B67] = trc_arib_std_b67,
|
||||
};
|
||||
|
||||
av_csp_trc_function av_csp_trc_func_from_id(enum AVColorTransferCharacteristic trc)
|
||||
{
|
||||
av_csp_trc_function func;
|
||||
if (trc >= AVCOL_TRC_NB)
|
||||
return NULL;
|
||||
func = trc_funcs[trc];
|
||||
if (!func)
|
||||
return NULL;
|
||||
return func;
|
||||
}
|
||||
|
|
|
|||
|
|
@ -1,5 +1,8 @@
|
|||
/*
|
||||
* Copyright (c) 2015 Kevin Wheatley <kevin.j.wheatley@gmail.com>
|
||||
* Copyright (c) 2016 Ronald S. Bultje <rsbultje@gmail.com>
|
||||
* Copyright (c) 2023 Leo Izen <leo.izen@gmail.com>
|
||||
*
|
||||
* This file is part of FFmpeg.
|
||||
*
|
||||
* FFmpeg is free software; you can redistribute it and/or
|
||||
|
|
@ -29,6 +32,7 @@
|
|||
* @ingroup lavu_math_csp
|
||||
* @author Ronald S. Bultje <rsbultje@gmail.com>
|
||||
* @author Leo Izen <leo.izen@gmail.com>
|
||||
* @author Kevin Wheatley <kevin.j.wheatley@gmail.com>
|
||||
*/
|
||||
|
||||
/**
|
||||
|
|
@ -76,6 +80,12 @@ typedef struct AVColorPrimariesDesc {
|
|||
AVPrimaryCoefficients prim;
|
||||
} AVColorPrimariesDesc;
|
||||
|
||||
/**
|
||||
* Function pointer representing a double -> double transfer function that performs
|
||||
* an EOTF transfer inversion. This function outputs linear light.
|
||||
*/
|
||||
typedef double (*av_csp_trc_function)(double);
|
||||
|
||||
/**
|
||||
* Retrieves the Luma coefficients necessary to construct a conversion matrix
|
||||
* from an enum constant describing the colorspace.
|
||||
|
|
@ -104,6 +114,35 @@ const AVColorPrimariesDesc *av_csp_primaries_desc_from_id(enum AVColorPrimaries
|
|||
*/
|
||||
enum AVColorPrimaries av_csp_primaries_id_from_desc(const AVColorPrimariesDesc *prm);
|
||||
|
||||
/**
|
||||
* Determine a suitable 'gamma' value to match the supplied
|
||||
* AVColorTransferCharacteristic.
|
||||
*
|
||||
* See Apple Technical Note TN2257 (https://developer.apple.com/library/mac/technotes/tn2257/_index.html)
|
||||
*
|
||||
* This function returns the gamma exponent for the OETF. For example, sRGB is approximated
|
||||
* by gamma 2.2, not by gamma 0.45455.
|
||||
*
|
||||
* @return Will return an approximation to the simple gamma function matching
|
||||
* the supplied Transfer Characteristic, Will return 0.0 for any
|
||||
* we cannot reasonably match against.
|
||||
*/
|
||||
double av_csp_approximate_trc_gamma(enum AVColorTransferCharacteristic trc);
|
||||
|
||||
/**
|
||||
* Determine the function needed to apply the given
|
||||
* AVColorTransferCharacteristic to linear input.
|
||||
*
|
||||
* The function returned should expect a nominal domain and range of [0.0-1.0]
|
||||
* values outside of this range maybe valid depending on the chosen
|
||||
* characteristic function.
|
||||
*
|
||||
* @return Will return pointer to the function matching the
|
||||
* supplied Transfer Characteristic. If unspecified will
|
||||
* return NULL:
|
||||
*/
|
||||
av_csp_trc_function av_csp_trc_func_from_id(enum AVColorTransferCharacteristic trc);
|
||||
|
||||
/**
|
||||
* @}
|
||||
*/
|
||||
|
|
|
|||
|
|
@ -19,7 +19,7 @@
|
|||
*/
|
||||
|
||||
#include <stdio.h>
|
||||
#include "libavutil/color_utils.c"
|
||||
#include "libavutil/csp.h"
|
||||
#include "libavutil/macros.h"
|
||||
|
||||
int main(int argc, char *argv[])
|
||||
|
|
@ -32,7 +32,7 @@ int main(int argc, char *argv[])
|
|||
};
|
||||
|
||||
for(i = 0; i < AVCOL_TRC_NB; i++) {
|
||||
avpriv_trc_function func = avpriv_get_trc_function_from_trc(i);
|
||||
av_csp_trc_function func = av_csp_trc_func_from_id(i);
|
||||
for(j = 0; j < FF_ARRAY_ELEMS(test_data); j++) {
|
||||
if(func != NULL) {
|
||||
double result = func(test_data[j]);
|
||||
|
|
|
|||
Loading…
Reference in New Issue