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mpv/video/csputils.c
Niklas Haas 329a7147d0 csp: document deviations from the references where they occur 
These mostly happen in situations where the correct behavior is
relatively new and not found in the wild (therefore not worth
implementing) and/or extremely complicated (and thus not worth worrying
about the potential edge cases and UI changes).

Still, it's best to document these where they happen to guide the poor
souls maintaining these files in the future.
2016-07-05 19:16:49 +02:00

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/*
* Common code related to colorspaces and conversion
*
* Copyleft (C) 2009 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
*
* mp_invert_cmat based on DarkPlaces engine, original code (GPL2 or later)
*
* This file is part of mpv.
*
* mpv 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.
*
* mpv 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 mpv. If not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include <stdint.h>
#include <math.h>
#include <assert.h>
#include <libavutil/common.h>
#include <libavcodec/avcodec.h>
#include "mp_image.h"
#include "csputils.h"
#include "options/m_option.h"
const struct m_opt_choice_alternatives mp_csp_names[] = {
{"auto", MP_CSP_AUTO},
{"bt.601", MP_CSP_BT_601},
{"bt.709", MP_CSP_BT_709},
{"smpte-240m", MP_CSP_SMPTE_240M},
{"bt.2020-ncl", MP_CSP_BT_2020_NC},
{"bt.2020-cl", MP_CSP_BT_2020_C},
{"rgb", MP_CSP_RGB},
{"xyz", MP_CSP_XYZ},
{"ycgco", MP_CSP_YCGCO},
{0}
};
const struct m_opt_choice_alternatives mp_csp_levels_names[] = {
{"auto", MP_CSP_LEVELS_AUTO},
{"limited", MP_CSP_LEVELS_TV},
{"full", MP_CSP_LEVELS_PC},
{0}
};
const struct m_opt_choice_alternatives mp_csp_prim_names[] = {
{"auto", MP_CSP_PRIM_AUTO},
{"bt.601-525", MP_CSP_PRIM_BT_601_525},
{"bt.601-625", MP_CSP_PRIM_BT_601_625},
{"bt.709", MP_CSP_PRIM_BT_709},
{"bt.2020", MP_CSP_PRIM_BT_2020},
{"bt.470m", MP_CSP_PRIM_BT_470M},
{"apple", MP_CSP_PRIM_APPLE},
{"adobe", MP_CSP_PRIM_ADOBE},
{"prophoto", MP_CSP_PRIM_PRO_PHOTO},
{"cie1931", MP_CSP_PRIM_CIE_1931},
{"dci-p3", MP_CSP_PRIM_DCI_P3},
{"v-gamut", MP_CSP_PRIM_V_GAMUT},
{0}
};
const struct m_opt_choice_alternatives mp_csp_trc_names[] = {
{"auto", MP_CSP_TRC_AUTO},
{"bt.1886", MP_CSP_TRC_BT_1886},
{"srgb", MP_CSP_TRC_SRGB},
{"linear", MP_CSP_TRC_LINEAR},
{"gamma1.8", MP_CSP_TRC_GAMMA18},
{"gamma2.2", MP_CSP_TRC_GAMMA22},
{"gamma2.8", MP_CSP_TRC_GAMMA28},
{"prophoto", MP_CSP_TRC_PRO_PHOTO},
{"st2084", MP_CSP_TRC_SMPTE_ST2084},
{"std-b67", MP_CSP_TRC_ARIB_STD_B67},
{"v-log", MP_CSP_TRC_V_LOG},
{0}
};
const char *const mp_csp_equalizer_names[MP_CSP_EQ_COUNT] = {
"brightness",
"contrast",
"hue",
"saturation",
"gamma",
"output-levels",
};
const struct m_opt_choice_alternatives mp_chroma_names[] = {
{"unknown", MP_CHROMA_AUTO},
{"mpeg2/4/h264",MP_CHROMA_LEFT},
{"mpeg1/jpeg", MP_CHROMA_CENTER},
{0}
};
// The short name _must_ match with what vf_stereo3d accepts (if supported).
// The long name in comments is closer to the Matroska spec (StereoMode element).
// The numeric index matches the Matroska StereoMode value. If you add entries
// that don't match Matroska, make sure demux_mkv.c rejects them properly.
const struct m_opt_choice_alternatives mp_stereo3d_names[] = {
{"no", -1}, // disable/invalid
{"mono", 0},
{"sbs2l", 1}, // "side_by_side_left"
{"ab2r", 2}, // "top_bottom_right"
{"ab2l", 3}, // "top_bottom_left"
{"checkr", 4}, // "checkboard_right" (unsupported by vf_stereo3d)
{"checkl", 5}, // "checkboard_left" (unsupported by vf_stereo3d)
{"irr", 6}, // "row_interleaved_right"
{"irl", 7}, // "row_interleaved_left"
{"icr", 8}, // "column_interleaved_right" (unsupported by vf_stereo3d)
{"icl", 9}, // "column_interleaved_left" (unsupported by vf_stereo3d)
{"arcc", 10}, // "anaglyph_cyan_red" (Matroska: unclear which mode)
{"sbs2r", 11}, // "side_by_side_right"
{"agmc", 12}, // "anaglyph_green_magenta" (Matroska: unclear which mode)
{"al", 13}, // "alternating frames left first"
{"ar", 14}, // "alternating frames right first"
{0}
};
enum mp_csp avcol_spc_to_mp_csp(int avcolorspace)
{
switch (avcolorspace) {
case AVCOL_SPC_BT709: return MP_CSP_BT_709;
case AVCOL_SPC_BT470BG: return MP_CSP_BT_601;
case AVCOL_SPC_BT2020_NCL: return MP_CSP_BT_2020_NC;
case AVCOL_SPC_BT2020_CL: return MP_CSP_BT_2020_C;
case AVCOL_SPC_SMPTE170M: return MP_CSP_BT_601;
case AVCOL_SPC_SMPTE240M: return MP_CSP_SMPTE_240M;
case AVCOL_SPC_RGB: return MP_CSP_RGB;
case AVCOL_SPC_YCOCG: return MP_CSP_YCGCO;
default: return MP_CSP_AUTO;
}
}
enum mp_csp_levels avcol_range_to_mp_csp_levels(int avrange)
{
switch (avrange) {
case AVCOL_RANGE_MPEG: return MP_CSP_LEVELS_TV;
case AVCOL_RANGE_JPEG: return MP_CSP_LEVELS_PC;
default: return MP_CSP_LEVELS_AUTO;
}
}
enum mp_csp_prim avcol_pri_to_mp_csp_prim(int avpri)
{
switch (avpri) {
case AVCOL_PRI_SMPTE240M: // Same as below
case AVCOL_PRI_SMPTE170M: return MP_CSP_PRIM_BT_601_525;
case AVCOL_PRI_BT470BG: return MP_CSP_PRIM_BT_601_625;
case AVCOL_PRI_BT709: return MP_CSP_PRIM_BT_709;
case AVCOL_PRI_BT2020: return MP_CSP_PRIM_BT_2020;
case AVCOL_PRI_BT470M: return MP_CSP_PRIM_BT_470M;
default: return MP_CSP_PRIM_AUTO;
}
}
enum mp_csp_trc avcol_trc_to_mp_csp_trc(int avtrc)
{
switch (avtrc) {
case AVCOL_TRC_BT709:
case AVCOL_TRC_SMPTE170M:
case AVCOL_TRC_SMPTE240M:
case AVCOL_TRC_BT1361_ECG:
case AVCOL_TRC_BT2020_10:
case AVCOL_TRC_BT2020_12: return MP_CSP_TRC_BT_1886;
case AVCOL_TRC_IEC61966_2_1: return MP_CSP_TRC_SRGB;
case AVCOL_TRC_LINEAR: return MP_CSP_TRC_LINEAR;
case AVCOL_TRC_GAMMA22: return MP_CSP_TRC_GAMMA22;
case AVCOL_TRC_GAMMA28: return MP_CSP_TRC_GAMMA28;
#if HAVE_AVUTIL_HDR
case AVCOL_TRC_SMPTEST2084: return MP_CSP_TRC_SMPTE_ST2084;
case AVCOL_TRC_ARIB_STD_B67: return MP_CSP_TRC_ARIB_STD_B67;
#endif
default: return MP_CSP_TRC_AUTO;
}
}
int mp_csp_to_avcol_spc(enum mp_csp colorspace)
{
switch (colorspace) {
case MP_CSP_BT_709: return AVCOL_SPC_BT709;
case MP_CSP_BT_601: return AVCOL_SPC_BT470BG;
case MP_CSP_BT_2020_NC: return AVCOL_SPC_BT2020_NCL;
case MP_CSP_BT_2020_C: return AVCOL_SPC_BT2020_CL;
case MP_CSP_SMPTE_240M: return AVCOL_SPC_SMPTE240M;
case MP_CSP_RGB: return AVCOL_SPC_RGB;
case MP_CSP_YCGCO: return AVCOL_SPC_YCOCG;
default: return AVCOL_SPC_UNSPECIFIED;
}
}
int mp_csp_levels_to_avcol_range(enum mp_csp_levels range)
{
switch (range) {
case MP_CSP_LEVELS_TV: return AVCOL_RANGE_MPEG;
case MP_CSP_LEVELS_PC: return AVCOL_RANGE_JPEG;
default: return AVCOL_RANGE_UNSPECIFIED;
}
}
int mp_csp_prim_to_avcol_pri(enum mp_csp_prim prim)
{
switch (prim) {
case MP_CSP_PRIM_BT_601_525: return AVCOL_PRI_SMPTE170M;
case MP_CSP_PRIM_BT_601_625: return AVCOL_PRI_BT470BG;
case MP_CSP_PRIM_BT_709: return AVCOL_PRI_BT709;
case MP_CSP_PRIM_BT_2020: return AVCOL_PRI_BT2020;
case MP_CSP_PRIM_BT_470M: return AVCOL_PRI_BT470M;
default: return AVCOL_PRI_UNSPECIFIED;
}
}
int mp_csp_trc_to_avcol_trc(enum mp_csp_trc trc)
{
switch (trc) {
// We just call it BT.1886 since we're decoding, but it's still BT.709
case MP_CSP_TRC_BT_1886: return AVCOL_TRC_BT709;
case MP_CSP_TRC_SRGB: return AVCOL_TRC_IEC61966_2_1;
case MP_CSP_TRC_LINEAR: return AVCOL_TRC_LINEAR;
case MP_CSP_TRC_GAMMA22: return AVCOL_TRC_GAMMA22;
case MP_CSP_TRC_GAMMA28: return AVCOL_TRC_GAMMA28;
#if HAVE_AVUTIL_HDR
case MP_CSP_TRC_SMPTE_ST2084: return AVCOL_TRC_SMPTEST2084;
case MP_CSP_TRC_ARIB_STD_B67: return AVCOL_TRC_ARIB_STD_B67;
#endif
default: return AVCOL_TRC_UNSPECIFIED;
}
}
enum mp_csp mp_csp_guess_colorspace(int width, int height)
{
return width >= 1280 || height > 576 ? MP_CSP_BT_709 : MP_CSP_BT_601;
}
enum mp_csp_prim mp_csp_guess_primaries(int width, int height)
{
// HD content
if (width >= 1280 || height > 576)
return MP_CSP_PRIM_BT_709;
switch (height) {
case 576: // Typical PAL content, including anamorphic/squared
return MP_CSP_PRIM_BT_601_625;
case 480: // Typical NTSC content, including squared
case 486: // NTSC Pro or anamorphic NTSC
return MP_CSP_PRIM_BT_601_525;
default: // No good metric, just pick BT.709 to minimize damage
return MP_CSP_PRIM_BT_709;
}
}
enum mp_chroma_location avchroma_location_to_mp(int avloc)
{
switch (avloc) {
case AVCHROMA_LOC_LEFT: return MP_CHROMA_LEFT;
case AVCHROMA_LOC_CENTER: return MP_CHROMA_CENTER;
default: return MP_CHROMA_AUTO;
}
}
int mp_chroma_location_to_av(enum mp_chroma_location mploc)
{
switch (mploc) {
case MP_CHROMA_LEFT: return AVCHROMA_LOC_LEFT;
case MP_CHROMA_CENTER: return AVCHROMA_LOC_CENTER;
default: return AVCHROMA_LOC_UNSPECIFIED;
}
}
// Return location of chroma samples relative to luma samples. 0/0 means
// centered. Other possible values are -1 (top/left) and +1 (right/bottom).
void mp_get_chroma_location(enum mp_chroma_location loc, int *x, int *y)
{
*x = 0;
*y = 0;
if (loc == MP_CHROMA_LEFT)
*x = -1;
}
void mp_invert_matrix3x3(float m[3][3])
{
float m00 = m[0][0], m01 = m[0][1], m02 = m[0][2],
m10 = m[1][0], m11 = m[1][1], m12 = m[1][2],
m20 = m[2][0], m21 = m[2][1], m22 = m[2][2];
// calculate the adjoint
m[0][0] = (m11 * m22 - m21 * m12);
m[0][1] = -(m01 * m22 - m21 * m02);
m[0][2] = (m01 * m12 - m11 * m02);
m[1][0] = -(m10 * m22 - m20 * m12);
m[1][1] = (m00 * m22 - m20 * m02);
m[1][2] = -(m00 * m12 - m10 * m02);
m[2][0] = (m10 * m21 - m20 * m11);
m[2][1] = -(m00 * m21 - m20 * m01);
m[2][2] = (m00 * m11 - m10 * m01);
// calculate the determinant (as inverse == 1/det * adjoint,
// adjoint * m == identity * det, so this calculates the det)
float det = m00 * m[0][0] + m10 * m[0][1] + m20 * m[0][2];
det = 1.0f / det;
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++)
m[i][j] *= det;
}
}
// A := A * B
static void mp_mul_matrix3x3(float a[3][3], float b[3][3])
{
float a00 = a[0][0], a01 = a[0][1], a02 = a[0][2],
a10 = a[1][0], a11 = a[1][1], a12 = a[1][2],
a20 = a[2][0], a21 = a[2][1], a22 = a[2][2];
for (int i = 0; i < 3; i++) {
a[0][i] = a00 * b[0][i] + a01 * b[1][i] + a02 * b[2][i];
a[1][i] = a10 * b[0][i] + a11 * b[1][i] + a12 * b[2][i];
a[2][i] = a20 * b[0][i] + a21 * b[1][i] + a22 * b[2][i];
}
}
// return the primaries associated with a certain mp_csp_primaries val
struct mp_csp_primaries mp_get_csp_primaries(enum mp_csp_prim spc)
{
/*
Values from: ITU-R Recommendations BT.470-6, BT.601-7, BT.709-5, BT.2020-0
https://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.470-6-199811-S!!PDF-E.pdf
https://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.601-7-201103-I!!PDF-E.pdf
https://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.709-5-200204-I!!PDF-E.pdf
https://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.2020-0-201208-I!!PDF-E.pdf
Other colorspaces from https://en.wikipedia.org/wiki/RGB_color_space#Specifications
*/
// CIE standard illuminant series
static const struct mp_csp_col_xy
d50 = {0.34577, 0.35850},
d65 = {0.31271, 0.32902},
c = {0.31006, 0.31616},
e = {1.0/3.0, 1.0/3.0};
switch (spc) {
case MP_CSP_PRIM_BT_470M:
return (struct mp_csp_primaries) {
.red = {0.670, 0.330},
.green = {0.210, 0.710},
.blue = {0.140, 0.080},
.white = c
};
case MP_CSP_PRIM_BT_601_525:
return (struct mp_csp_primaries) {
.red = {0.630, 0.340},
.green = {0.310, 0.595},
.blue = {0.155, 0.070},
.white = d65
};
case MP_CSP_PRIM_BT_601_625:
return (struct mp_csp_primaries) {
.red = {0.640, 0.330},
.green = {0.290, 0.600},
.blue = {0.150, 0.060},
.white = d65
};
// This is the default assumption if no colorspace information could
// be determined, eg. for files which have no video channel.
case MP_CSP_PRIM_AUTO:
case MP_CSP_PRIM_BT_709:
return (struct mp_csp_primaries) {
.red = {0.640, 0.330},
.green = {0.300, 0.600},
.blue = {0.150, 0.060},
.white = d65
};
case MP_CSP_PRIM_BT_2020:
return (struct mp_csp_primaries) {
.red = {0.708, 0.292},
.green = {0.170, 0.797},
.blue = {0.131, 0.046},
.white = d65
};
case MP_CSP_PRIM_APPLE:
return (struct mp_csp_primaries) {
.red = {0.625, 0.340},
.green = {0.280, 0.595},
.blue = {0.115, 0.070},
.white = d65
};
case MP_CSP_PRIM_ADOBE:
return (struct mp_csp_primaries) {
.red = {0.640, 0.330},
.green = {0.210, 0.710},
.blue = {0.150, 0.060},
.white = d65
};
case MP_CSP_PRIM_PRO_PHOTO:
return (struct mp_csp_primaries) {
.red = {0.7347, 0.2653},
.green = {0.1596, 0.8404},
.blue = {0.0366, 0.0001},
.white = d50
};
case MP_CSP_PRIM_CIE_1931:
return (struct mp_csp_primaries) {
.red = {0.7347, 0.2653},
.green = {0.2738, 0.7174},
.blue = {0.1666, 0.0089},
.white = e
};
// From SMPTE RP 431-2
case MP_CSP_PRIM_DCI_P3:
return (struct mp_csp_primaries) {
.red = {0.680, 0.320},
.green = {0.265, 0.690},
.blue = {0.150, 0.060},
.white = d65
};
// From Panasonic VARICAM reference manual
case MP_CSP_PRIM_V_GAMUT:
return (struct mp_csp_primaries) {
.red = {0.730, 0.280},
.green = {0.165, 0.840},
.blue = {0.100, -0.03},
.white = d65
};
default:
return (struct mp_csp_primaries) {{0}};
}
}
// Get the nominal peak for a given colorspace, based on a known reference peak
// (i.e. the display of a reference white illuminant. This may or may not
// be the actual signal peak)
float mp_csp_trc_nom_peak(enum mp_csp_trc trc, float ref_peak)
{
switch (trc) {
case MP_CSP_TRC_SMPTE_ST2084: return 10000; // fixed peak
case MP_CSP_TRC_ARIB_STD_B67: return 12.0 * ref_peak;
case MP_CSP_TRC_V_LOG: return 46.0855 * ref_peak;
}
return ref_peak;
}
bool mp_trc_is_hdr(enum mp_csp_trc trc)
{
switch (trc) {
case MP_CSP_TRC_SMPTE_ST2084:
case MP_CSP_TRC_ARIB_STD_B67:
case MP_CSP_TRC_V_LOG:
return true;
}
return false;
}
// Compute the RGB/XYZ matrix as described here:
// http://www.brucelindbloom.com/index.html?Eqn_RGB_XYZ_Matrix.html
static void mp_get_rgb2xyz_matrix(struct mp_csp_primaries space, float m[3][3])
{
float S[3], X[4], Z[4];
// Convert from CIE xyY to XYZ. Note that Y=1 holds true for all primaries
X[0] = space.red.x / space.red.y;
X[1] = space.green.x / space.green.y;
X[2] = space.blue.x / space.blue.y;
X[3] = space.white.x / space.white.y;
Z[0] = (1 - space.red.x - space.red.y) / space.red.y;
Z[1] = (1 - space.green.x - space.green.y) / space.green.y;
Z[2] = (1 - space.blue.x - space.blue.y) / space.blue.y;
Z[3] = (1 - space.white.x - space.white.y) / space.white.y;
// S = XYZ^-1 * W
for (int i = 0; i < 3; i++) {
m[0][i] = X[i];
m[1][i] = 1;
m[2][i] = Z[i];
}
mp_invert_matrix3x3(m);
for (int i = 0; i < 3; i++)
S[i] = m[i][0] * X[3] + m[i][1] * 1 + m[i][2] * Z[3];
// M = [Sc * XYZc]
for (int i = 0; i < 3; i++) {
m[0][i] = S[i] * X[i];
m[1][i] = S[i] * 1;
m[2][i] = S[i] * Z[i];
}
}
// M := M * XYZd<-XYZs
static void mp_apply_chromatic_adaptation(struct mp_csp_col_xy src,
struct mp_csp_col_xy dest, float m[3][3])
{
// If the white points are nearly identical, this is a wasteful identity
// operation.
if (fabs(src.x - dest.x) < 1e-6 && fabs(src.y - dest.y) < 1e-6)
return;
// XYZd<-XYZs = Ma^-1 * (I*[Cd/Cs]) * Ma
// http://www.brucelindbloom.com/index.html?Eqn_ChromAdapt.html
float C[3][2], tmp[3][3] = {{0}};
// Ma = Bradford matrix, arguably most popular method in use today.
// This is derived experimentally and thus hard-coded.
float bradford[3][3] = {
{ 0.8951, 0.2664, -0.1614 },
{ -0.7502, 1.7135, 0.0367 },
{ 0.0389, -0.0685, 1.0296 },
};
for (int i = 0; i < 3; i++) {
// source cone
C[i][0] = bradford[i][0] * src.x / src.y
+ bradford[i][1] * 1
+ bradford[i][2] * (1 - src.x - src.y) / src.y;
// dest cone
C[i][1] = bradford[i][0] * dest.x / dest.y
+ bradford[i][1] * 1
+ bradford[i][2] * (1 - dest.x - dest.y) / dest.y;
}
// tmp := I * [Cd/Cs] * Ma
for (int i = 0; i < 3; i++)
tmp[i][i] = C[i][1] / C[i][0];
mp_mul_matrix3x3(tmp, bradford);
// M := M * Ma^-1 * tmp
mp_invert_matrix3x3(bradford);
mp_mul_matrix3x3(m, bradford);
mp_mul_matrix3x3(m, tmp);
}
// get the coefficients of the source -> dest cms matrix
void mp_get_cms_matrix(struct mp_csp_primaries src, struct mp_csp_primaries dest,
enum mp_render_intent intent, float m[3][3])
{
float tmp[3][3];
// In saturation mapping, we don't care about accuracy and just want
// primaries to map to primaries, making this an identity transformation.
if (intent == MP_INTENT_SATURATION) {
for (int i = 0; i < 3; i++)
m[i][i] = 1;
return;
}
// RGBd<-RGBs = RGBd<-XYZd * XYZd<-XYZs * XYZs<-RGBs
// Equations from: http://www.brucelindbloom.com/index.html?Math.html
// Note: Perceptual is treated like relative colorimetric. There's no
// definition for perceptual other than "make it look good".
// RGBd<-XYZd, inverted from XYZd<-RGBd
mp_get_rgb2xyz_matrix(dest, m);
mp_invert_matrix3x3(m);
// Chromatic adaptation, except in absolute colorimetric intent
if (intent != MP_INTENT_ABSOLUTE_COLORIMETRIC)
mp_apply_chromatic_adaptation(src.white, dest.white, m);
// XYZs<-RGBs
mp_get_rgb2xyz_matrix(src, tmp);
mp_mul_matrix3x3(m, tmp);
}
// get the coefficients of an SMPTE 428-1 xyz -> rgb conversion matrix
// intent = the rendering intent used to convert to the target primaries
static void mp_get_xyz2rgb_coeffs(struct mp_csp_params *params,
enum mp_render_intent intent, struct mp_cmat *m)
{
struct mp_csp_primaries prim = mp_get_csp_primaries(params->color.primaries);
float brightness = params->brightness;
mp_get_rgb2xyz_matrix(prim, m->m);
mp_invert_matrix3x3(m->m);
// All non-absolute mappings want to map source white to target white
if (intent != MP_INTENT_ABSOLUTE_COLORIMETRIC) {
// SMPTE 428-1 defines the calibration white point as CIE xy (0.314, 0.351)
static const struct mp_csp_col_xy smpte428 = {0.314, 0.351};
mp_apply_chromatic_adaptation(smpte428, prim.white, m->m);
}
// Since this outputs linear RGB rather than companded RGB, we
// want to linearize any brightness additions. 2 is a reasonable
// approximation for any sort of gamma function that could be in use.
// As this is an aesthetic setting only, any exact values do not matter.
brightness *= fabs(brightness);
for (int i = 0; i < 3; i++)
m->c[i] = brightness;
}
// Get multiplication factor required if image data is fit within the LSBs of a
// higher smaller bit depth isfixed-point texture data.
double mp_get_csp_mul(enum mp_csp csp, int input_bits, int texture_bits)
{
assert(texture_bits >= input_bits);
// Convenience for some irrelevant cases, e.g. rgb565 or disabling expansion.
if (!input_bits)
return 1;
// RGB always uses the full range available.
if (csp == MP_CSP_RGB)
return ((1LL << input_bits) - 1.) / ((1LL << texture_bits) - 1.);
if (csp == MP_CSP_XYZ)
return 1;
// High bit depth YUV uses a range shifted from 8 bit.
return (1LL << input_bits) / ((1LL << texture_bits) - 1.) * 255 / 256;
}
/* Fill in the Y, U, V vectors of a yuv-to-rgb conversion matrix
* based on the given luma weights of the R, G and B components (lr, lg, lb).
* lr+lg+lb is assumed to equal 1.
* This function is meant for colorspaces satisfying the following
* conditions (which are true for common YUV colorspaces):
* - The mapping from input [Y, U, V] to output [R, G, B] is linear.
* - Y is the vector [1, 1, 1]. (meaning input Y component maps to 1R+1G+1B)
* - U maps to a value with zero R and positive B ([0, x, y], y > 0;
* i.e. blue and green only).
* - V maps to a value with zero B and positive R ([x, y, 0], x > 0;
* i.e. red and green only).
* - U and V are orthogonal to the luma vector [lr, lg, lb].
* - The magnitudes of the vectors U and V are the minimal ones for which
* the image of the set Y=[0...1],U=[-0.5...0.5],V=[-0.5...0.5] under the
* conversion function will cover the set R=[0...1],G=[0...1],B=[0...1]
* (the resulting matrix can be converted for other input/output ranges
* outside this function).
* Under these conditions the given parameters lr, lg, lb uniquely
* determine the mapping of Y, U, V to R, G, B.
*/
static void luma_coeffs(struct mp_cmat *mat, float lr, float lg, float lb)
{
assert(fabs(lr+lg+lb - 1) < 1e-6);
*mat = (struct mp_cmat) {
{ {1, 0, 2 * (1-lr) },
{1, -2 * (1-lb) * lb/lg, -2 * (1-lr) * lr/lg },
{1, 2 * (1-lb), 0 } },
// Constant coefficients (mat->c) not set here
};
}
// get the coefficients of the yuv -> rgb conversion matrix
void mp_get_csp_matrix(struct mp_csp_params *params, struct mp_cmat *m)
{
enum mp_csp colorspace = params->color.space;
if (colorspace <= MP_CSP_AUTO || colorspace >= MP_CSP_COUNT)
colorspace = MP_CSP_BT_601;
enum mp_csp_levels levels_in = params->color.levels;
if (levels_in <= MP_CSP_LEVELS_AUTO || levels_in >= MP_CSP_LEVELS_COUNT)
levels_in = MP_CSP_LEVELS_TV;
switch (colorspace) {
case MP_CSP_BT_601: luma_coeffs(m, 0.299, 0.587, 0.114 ); break;
case MP_CSP_BT_709: luma_coeffs(m, 0.2126, 0.7152, 0.0722); break;
case MP_CSP_SMPTE_240M: luma_coeffs(m, 0.2122, 0.7013, 0.0865); break;
case MP_CSP_BT_2020_NC: luma_coeffs(m, 0.2627, 0.6780, 0.0593); break;
case MP_CSP_BT_2020_C: {
// Note: This outputs into the [-0.5,0.5] range for chroma information.
// If this clips on any VO, a constant 0.5 coefficient can be added
// to the chroma channels to normalize them into [0,1]. This is not
// currently needed by anything, though.
*m = (struct mp_cmat){{{0, 0, 1}, {1, 0, 0}, {0, 1, 0}}};
break;
}
case MP_CSP_RGB: {
*m = (struct mp_cmat){{{1, 0, 0}, {0, 1, 0}, {0, 0, 1}}};
levels_in = -1;
break;
}
case MP_CSP_XYZ: {
// The vo should probably not be using a matrix generated by this
// function for XYZ sources, but if it does, let's just assume it
// wants BT.709 with D65 white point (virtually all other content).
mp_get_xyz2rgb_coeffs(params, MP_INTENT_RELATIVE_COLORIMETRIC, m);
levels_in = -1;
break;
}
case MP_CSP_YCGCO: {
*m = (struct mp_cmat) {
{{1, -1, 1},
{1, 1, 0},
{1, -1, -1}},
};
break;
}
default:
abort();
};
if ((colorspace == MP_CSP_BT_601 || colorspace == MP_CSP_BT_709 ||
colorspace == MP_CSP_SMPTE_240M || colorspace == MP_CSP_BT_2020_NC))
{
// Hue is equivalent to rotating input [U, V] subvector around the origin.
// Saturation scales [U, V].
float huecos = params->gray ? 0 : params->saturation * cos(params->hue);
float huesin = params->gray ? 0 : params->saturation * sin(params->hue);
for (int i = 0; i < 3; i++) {
float u = m->m[i][1], v = m->m[i][2];
m->m[i][1] = huecos * u - huesin * v;
m->m[i][2] = huesin * u + huecos * v;
}
}
// The values below are written in 0-255 scale - thus bring s into range.
double s =
mp_get_csp_mul(colorspace, params->input_bits, params->texture_bits) / 255;
// NOTE: The yuvfull ranges as presented here are arguably ambiguous,
// and conflict with at least the full-range YCbCr/ICtCp values as defined
// by ITU-R BT.2100. If somebody ever complains about full-range YUV looking
// different from their reference display, this comment is probably why.
struct yuvlevels { double ymin, ymax, cmin, cmid; }
yuvlim = { 16*s, 235*s, 16*s, 128*s },
yuvfull = { 0*s, 255*s, 1*s, 128*s }, // '1' for symmetry around 128
anyfull = { 0*s, 255*s, -255*s/2, 0 },
yuvlev;
switch (levels_in) {
case MP_CSP_LEVELS_TV: yuvlev = yuvlim; break;
case MP_CSP_LEVELS_PC: yuvlev = yuvfull; break;
case -1: yuvlev = anyfull; break;
default:
abort();
}
int levels_out = params->levels_out;
if (levels_out <= MP_CSP_LEVELS_AUTO || levels_out >= MP_CSP_LEVELS_COUNT)
levels_out = MP_CSP_LEVELS_PC;
struct rgblevels { double min, max; }
rgblim = { 16/255., 235/255. },
rgbfull = { 0, 1 },
rgblev;
switch (levels_out) {
case MP_CSP_LEVELS_TV: rgblev = rgblim; break;
case MP_CSP_LEVELS_PC: rgblev = rgbfull; break;
default:
abort();
}
double ymul = (rgblev.max - rgblev.min) / (yuvlev.ymax - yuvlev.ymin);
double cmul = (rgblev.max - rgblev.min) / (yuvlev.cmid - yuvlev.cmin) / 2;
// Contrast scales the output value range (gain)
ymul *= params->contrast;
cmul *= params->contrast;
for (int i = 0; i < 3; i++) {
m->m[i][0] *= ymul;
m->m[i][1] *= cmul;
m->m[i][2] *= cmul;
// Set c so that Y=umin,UV=cmid maps to RGB=min (black to black),
// also add brightness offset (black lift)
m->c[i] = rgblev.min - m->m[i][0] * yuvlev.ymin
- (m->m[i][1] + m->m[i][2]) * yuvlev.cmid
+ params->brightness;
}
}
// Set colorspace related fields in p from f. Don't touch other fields.
void mp_csp_set_image_params(struct mp_csp_params *params,
const struct mp_image_params *imgparams)
{
struct mp_image_params p = *imgparams;
mp_image_params_guess_csp(&p); // ensure consistency
params->color = p.color;
}
bool mp_colorspace_equal(struct mp_colorspace c1, struct mp_colorspace c2)
{
return c1.space == c2.space &&
c1.levels == c2.levels &&
c1.primaries == c2.primaries &&
c1.gamma == c2.gamma &&
c1.sig_peak == c2.sig_peak &&
c1.nom_peak == c2.nom_peak;
}
// Copy settings from eq into params.
void mp_csp_copy_equalizer_values(struct mp_csp_params *params,
const struct mp_csp_equalizer *eq)
{
params->brightness = eq->values[MP_CSP_EQ_BRIGHTNESS] / 100.0;
params->contrast = (eq->values[MP_CSP_EQ_CONTRAST] + 100) / 100.0;
params->hue = eq->values[MP_CSP_EQ_HUE] / 100.0 * M_PI;
params->saturation = (eq->values[MP_CSP_EQ_SATURATION] + 100) / 100.0;
params->gamma = exp(log(8.0) * eq->values[MP_CSP_EQ_GAMMA] / 100.0);
params->levels_out = eq->values[MP_CSP_EQ_OUTPUT_LEVELS];
}
static int find_eq(int capabilities, const char *name)
{
for (int i = 0; i < MP_CSP_EQ_COUNT; i++) {
if (strcmp(name, mp_csp_equalizer_names[i]) == 0)
return ((1 << i) & capabilities) ? i : -1;
}
return -1;
}
int mp_csp_equalizer_get(struct mp_csp_equalizer *eq, const char *property,
int *out_value)
{
int index = find_eq(eq->capabilities, property);
if (index < 0)
return -1;
*out_value = eq->values[index];
return 0;
}
int mp_csp_equalizer_set(struct mp_csp_equalizer *eq, const char *property,
int value)
{
int index = find_eq(eq->capabilities, property);
if (index < 0)
return 0;
eq->values[index] = value;
return 1;
}
void mp_invert_cmat(struct mp_cmat *out, struct mp_cmat *in)
{
*out = *in;
mp_invert_matrix3x3(out->m);
// fix the constant coefficient
// rgb = M * yuv + C
// M^-1 * rgb = yuv + M^-1 * C
// yuv = M^-1 * rgb - M^-1 * C
// ^^^^^^^^^^
out->c[0] = -(out->m[0][0] * in->c[0] + out->m[0][1] * in->c[1] + out->m[0][2] * in->c[2]);
out->c[1] = -(out->m[1][0] * in->c[0] + out->m[1][1] * in->c[1] + out->m[1][2] * in->c[2]);
out->c[2] = -(out->m[2][0] * in->c[0] + out->m[2][1] * in->c[1] + out->m[2][2] * in->c[2]);
}
// Multiply the color in c with the given matrix.
// i/o is {R, G, B} or {Y, U, V} (depending on input/output and matrix), using
// a fixed point representation with the given number of bits (so for bits==8,
// [0,255] maps to [0,1]). The output is clipped to the range as needed.
void mp_map_fixp_color(struct mp_cmat *matrix, int ibits, int in[3],
int obits, int out[3])
{
for (int i = 0; i < 3; i++) {
double val = matrix->c[i];
for (int x = 0; x < 3; x++)
val += matrix->m[i][x] * in[x] / ((1 << ibits) - 1);
int ival = lrint(val * ((1 << obits) - 1));
out[i] = av_clip(ival, 0, (1 << obits) - 1);
}
}
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