| // 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; |
| } |
