| Current File : //usr/local/src/libavif-0.11.1/src/colr.c |
// Copyright 2019 Joe Drago. All rights reserved.
// SPDX-License-Identifier: BSD-2-Clause
#include "avif/internal.h"
#include <math.h>
#include <string.h>
struct avifColorPrimariesTable
{
avifColorPrimaries colorPrimariesEnum;
const char * name;
float primaries[8]; // rX, rY, gX, gY, bX, bY, wX, wY
};
static const struct avifColorPrimariesTable avifColorPrimariesTables[] = {
{ AVIF_COLOR_PRIMARIES_BT709, "BT.709", { 0.64f, 0.33f, 0.3f, 0.6f, 0.15f, 0.06f, 0.3127f, 0.329f } },
{ AVIF_COLOR_PRIMARIES_BT470M, "BT.470-6 System M", { 0.67f, 0.33f, 0.21f, 0.71f, 0.14f, 0.08f, 0.310f, 0.316f } },
{ AVIF_COLOR_PRIMARIES_BT470BG, "BT.470-6 System BG", { 0.64f, 0.33f, 0.29f, 0.60f, 0.15f, 0.06f, 0.3127f, 0.3290f } },
{ AVIF_COLOR_PRIMARIES_BT601, "BT.601", { 0.630f, 0.340f, 0.310f, 0.595f, 0.155f, 0.070f, 0.3127f, 0.3290f } },
{ AVIF_COLOR_PRIMARIES_SMPTE240, "SMPTE 240M", { 0.630f, 0.340f, 0.310f, 0.595f, 0.155f, 0.070f, 0.3127f, 0.3290f } },
{ AVIF_COLOR_PRIMARIES_GENERIC_FILM, "Generic film", { 0.681f, 0.319f, 0.243f, 0.692f, 0.145f, 0.049f, 0.310f, 0.316f } },
{ AVIF_COLOR_PRIMARIES_BT2020, "BT.2020", { 0.708f, 0.292f, 0.170f, 0.797f, 0.131f, 0.046f, 0.3127f, 0.3290f } },
{ AVIF_COLOR_PRIMARIES_XYZ, "XYZ", { 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.3333f, 0.3333f } },
{ AVIF_COLOR_PRIMARIES_SMPTE431, "SMPTE RP 431-2", { 0.680f, 0.320f, 0.265f, 0.690f, 0.150f, 0.060f, 0.314f, 0.351f } },
{ AVIF_COLOR_PRIMARIES_SMPTE432, "SMPTE EG 432-1 (DCI P3)", { 0.680f, 0.320f, 0.265f, 0.690f, 0.150f, 0.060f, 0.3127f, 0.3290f } },
{ AVIF_COLOR_PRIMARIES_EBU3213, "EBU Tech. 3213-E", { 0.630f, 0.340f, 0.295f, 0.605f, 0.155f, 0.077f, 0.3127f, 0.3290f } }
};
static const int avifColorPrimariesTableSize = sizeof(avifColorPrimariesTables) / sizeof(avifColorPrimariesTables[0]);
void avifColorPrimariesGetValues(avifColorPrimaries acp, float outPrimaries[8])
{
for (int i = 0; i < avifColorPrimariesTableSize; ++i) {
if (avifColorPrimariesTables[i].colorPrimariesEnum == acp) {
memcpy(outPrimaries, avifColorPrimariesTables[i].primaries, sizeof(avifColorPrimariesTables[i].primaries));
return;
}
}
// if we get here, the color primaries are unknown. Just return a reasonable default.
memcpy(outPrimaries, avifColorPrimariesTables[0].primaries, sizeof(avifColorPrimariesTables[0].primaries));
}
static avifBool matchesTo3RoundedPlaces(float a, float b)
{
return (fabsf(a - b) < 0.001f);
}
static avifBool primariesMatch(const float p1[8], const float p2[8])
{
return matchesTo3RoundedPlaces(p1[0], p2[0]) && matchesTo3RoundedPlaces(p1[1], p2[1]) &&
matchesTo3RoundedPlaces(p1[2], p2[2]) && matchesTo3RoundedPlaces(p1[3], p2[3]) && matchesTo3RoundedPlaces(p1[4], p2[4]) &&
matchesTo3RoundedPlaces(p1[5], p2[5]) && matchesTo3RoundedPlaces(p1[6], p2[6]) && matchesTo3RoundedPlaces(p1[7], p2[7]);
}
avifColorPrimaries avifColorPrimariesFind(const float inPrimaries[8], const char ** outName)
{
if (outName) {
*outName = NULL;
}
for (int i = 0; i < avifColorPrimariesTableSize; ++i) {
if (primariesMatch(inPrimaries, avifColorPrimariesTables[i].primaries)) {
if (outName) {
*outName = avifColorPrimariesTables[i].name;
}
return avifColorPrimariesTables[i].colorPrimariesEnum;
}
}
return AVIF_COLOR_PRIMARIES_UNKNOWN;
}
struct avifMatrixCoefficientsTable
{
avifMatrixCoefficients matrixCoefficientsEnum;
const char * name;
const float kr;
const float kb;
};
// https://www.itu.int/rec/T-REC-H.273-201612-I/en
static const struct avifMatrixCoefficientsTable matrixCoefficientsTables[] = {
//{ AVIF_MATRIX_COEFFICIENTS_IDENTITY, "Identity", 0.0f, 0.0f, }, // Handled elsewhere
{ AVIF_MATRIX_COEFFICIENTS_BT709, "BT.709", 0.2126f, 0.0722f },
{ AVIF_MATRIX_COEFFICIENTS_FCC, "FCC USFC 73.682", 0.30f, 0.11f },
{ AVIF_MATRIX_COEFFICIENTS_BT470BG, "BT.470-6 System BG", 0.299f, 0.114f },
{ AVIF_MATRIX_COEFFICIENTS_BT601, "BT.601", 0.299f, 0.114f },
{ AVIF_MATRIX_COEFFICIENTS_SMPTE240, "SMPTE ST 240", 0.212f, 0.087f },
//{ AVIF_MATRIX_COEFFICIENTS_YCGCO, "YCgCo", 0.0f, 0.0f, }, // Handled elsewhere
{ AVIF_MATRIX_COEFFICIENTS_BT2020_NCL, "BT.2020 (non-constant luminance)", 0.2627f, 0.0593f },
//{ AVIF_MATRIX_COEFFICIENTS_BT2020_CL, "BT.2020 (constant luminance)", 0.2627f, 0.0593f }, // FIXME: It is not an linear transformation.
//{ AVIF_MATRIX_COEFFICIENTS_SMPTE2085, "ST 2085", 0.0f, 0.0f }, // FIXME: ST2085 can't represent using Kr and Kb.
//{ AVIF_MATRIX_COEFFICIENTS_CHROMA_DERIVED_CL, "Chromaticity-derived constant luminance system", 0.0f, 0.0f } // FIXME: It is not an linear transformation.
//{ AVIF_MATRIX_COEFFICIENTS_ICTCP, "BT.2100-0 ICtCp", 0.0f, 0.0f }, // FIXME: This can't represent using Kr and Kb.
};
static const int avifMatrixCoefficientsTableSize = sizeof(matrixCoefficientsTables) / sizeof(matrixCoefficientsTables[0]);
static avifBool calcYUVInfoFromCICP(const avifImage * image, float coeffs[3])
{
if (image->matrixCoefficients == AVIF_MATRIX_COEFFICIENTS_CHROMA_DERIVED_NCL) {
float primaries[8];
avifColorPrimariesGetValues(image->colorPrimaries, primaries);
float const rX = primaries[0];
float const rY = primaries[1];
float const gX = primaries[2];
float const gY = primaries[3];
float const bX = primaries[4];
float const bY = primaries[5];
float const wX = primaries[6];
float const wY = primaries[7];
float const rZ = 1.0f - (rX + rY); // (Eq. 34)
float const gZ = 1.0f - (gX + gY); // (Eq. 35)
float const bZ = 1.0f - (bX + bY); // (Eq. 36)
float const wZ = 1.0f - (wX + wY); // (Eq. 37)
float const kr = (rY * (wX * (gY * bZ - bY * gZ) + wY * (bX * gZ - gX * bZ) + wZ * (gX * bY - bX * gY))) /
(wY * (rX * (gY * bZ - bY * gZ) + gX * (bY * rZ - rY * bZ) + bX * (rY * gZ - gY * rZ)));
// (Eq. 32)
float const kb = (bY * (wX * (rY * gZ - gY * rZ) + wY * (gX * rZ - rX * gZ) + wZ * (rX * gY - gX * rY))) /
(wY * (rX * (gY * bZ - bY * gZ) + gX * (bY * rZ - rY * bZ) + bX * (rY * gZ - gY * rZ)));
// (Eq. 33)
coeffs[0] = kr;
coeffs[2] = kb;
coeffs[1] = 1.0f - coeffs[0] - coeffs[2];
return AVIF_TRUE;
} else {
for (int i = 0; i < avifMatrixCoefficientsTableSize; ++i) {
const struct avifMatrixCoefficientsTable * const table = &matrixCoefficientsTables[i];
if (table->matrixCoefficientsEnum == image->matrixCoefficients) {
coeffs[0] = table->kr;
coeffs[2] = table->kb;
coeffs[1] = 1.0f - coeffs[0] - coeffs[2];
return AVIF_TRUE;
}
}
}
return AVIF_FALSE;
}
void avifCalcYUVCoefficients(const avifImage * image, float * outR, float * outG, float * outB)
{
// (As of ISO/IEC 23000-22:2019 Amendment 2)
// MIAF Section 7.3.6.4 "Colour information property":
//
// If a coded image has no associated colour property, the default property is defined as having
// colour_type equal to 'nclx' with properties as follows:
// - colour_primaries equal to 1,
// - transfer_characteristics equal to 13,
// - matrix_coefficients equal to 5 or 6 (which are functionally identical), and
// - full_range_flag equal to 1.
// Only if the colour information property of the image matches these default values, the colour
// property may be omitted; all other images shall have an explicitly declared colour space via
// association with a property of this type.
//
// See here for the discussion: https://github.com/AOMediaCodec/av1-avif/issues/77#issuecomment-676526097
// matrix_coefficients of [5,6] == BT.601:
float kr = 0.299f;
float kb = 0.114f;
float kg = 1.0f - kr - kb;
float coeffs[3];
if (calcYUVInfoFromCICP(image, coeffs)) {
kr = coeffs[0];
kg = coeffs[1];
kb = coeffs[2];
}
*outR = kr;
*outG = kg;
*outB = kb;
}