diff options
Diffstat (limited to 'lib/icc.cpp')
-rw-r--r-- | lib/icc.cpp | 1148 |
1 files changed, 570 insertions, 578 deletions
diff --git a/lib/icc.cpp b/lib/icc.cpp index 5032bea..851dd9d 100644 --- a/lib/icc.cpp +++ b/lib/icc.cpp @@ -22,667 +22,659 @@ namespace ultrahdr { static void Matrix3x3_apply(const Matrix3x3* m, float* x) { - float y0 = x[0] * m->vals[0][0] + x[1] * m->vals[0][1] + x[2] * m->vals[0][2]; - float y1 = x[0] * m->vals[1][0] + x[1] * m->vals[1][1] + x[2] * m->vals[1][2]; - float y2 = x[0] * m->vals[2][0] + x[1] * m->vals[2][1] + x[2] * m->vals[2][2]; - x[0] = y0; - x[1] = y1; - x[2] = y2; + float y0 = x[0] * m->vals[0][0] + x[1] * m->vals[0][1] + x[2] * m->vals[0][2]; + float y1 = x[0] * m->vals[1][0] + x[1] * m->vals[1][1] + x[2] * m->vals[1][2]; + float y2 = x[0] * m->vals[2][0] + x[1] * m->vals[2][1] + x[2] * m->vals[2][2]; + x[0] = y0; + x[1] = y1; + x[2] = y2; } bool Matrix3x3_invert(const Matrix3x3* src, Matrix3x3* dst) { - double a00 = src->vals[0][0], - a01 = src->vals[1][0], - a02 = src->vals[2][0], - a10 = src->vals[0][1], - a11 = src->vals[1][1], - a12 = src->vals[2][1], - a20 = src->vals[0][2], - a21 = src->vals[1][2], - a22 = src->vals[2][2]; - - double b0 = a00*a11 - a01*a10, - b1 = a00*a12 - a02*a10, - b2 = a01*a12 - a02*a11, - b3 = a20, - b4 = a21, - b5 = a22; - - double determinant = b0*b5 - - b1*b4 - + b2*b3; - - if (determinant == 0) { - return false; - } - - double invdet = 1.0 / determinant; - if (invdet > +FLT_MAX || invdet < -FLT_MAX || !isfinitef_((float)invdet)) { - return false; - } - - b0 *= invdet; - b1 *= invdet; - b2 *= invdet; - b3 *= invdet; - b4 *= invdet; - b5 *= invdet; - - dst->vals[0][0] = (float)( a11*b5 - a12*b4 ); - dst->vals[1][0] = (float)( a02*b4 - a01*b5 ); - dst->vals[2][0] = (float)( + b2 ); - dst->vals[0][1] = (float)( a12*b3 - a10*b5 ); - dst->vals[1][1] = (float)( a00*b5 - a02*b3 ); - dst->vals[2][1] = (float)( - b1 ); - dst->vals[0][2] = (float)( a10*b4 - a11*b3 ); - dst->vals[1][2] = (float)( a01*b3 - a00*b4 ); - dst->vals[2][2] = (float)( + b0 ); - - for (int r = 0; r < 3; ++r) + double a00 = src->vals[0][0]; + double a01 = src->vals[1][0]; + double a02 = src->vals[2][0]; + double a10 = src->vals[0][1]; + double a11 = src->vals[1][1]; + double a12 = src->vals[2][1]; + double a20 = src->vals[0][2]; + double a21 = src->vals[1][2]; + double a22 = src->vals[2][2]; + + double b0 = a00 * a11 - a01 * a10; + double b1 = a00 * a12 - a02 * a10; + double b2 = a01 * a12 - a02 * a11; + double b3 = a20; + double b4 = a21; + double b5 = a22; + + double determinant = b0 * b5 - b1 * b4 + b2 * b3; + + if (determinant == 0) { + return false; + } + + double invdet = 1.0 / determinant; + if (invdet > +FLT_MAX || invdet < -FLT_MAX || !isfinitef_((float)invdet)) { + return false; + } + + b0 *= invdet; + b1 *= invdet; + b2 *= invdet; + b3 *= invdet; + b4 *= invdet; + b5 *= invdet; + + dst->vals[0][0] = (float)(a11 * b5 - a12 * b4); + dst->vals[1][0] = (float)(a02 * b4 - a01 * b5); + dst->vals[2][0] = (float)(+b2); + dst->vals[0][1] = (float)(a12 * b3 - a10 * b5); + dst->vals[1][1] = (float)(a00 * b5 - a02 * b3); + dst->vals[2][1] = (float)(-b1); + dst->vals[0][2] = (float)(a10 * b4 - a11 * b3); + dst->vals[1][2] = (float)(a01 * b3 - a00 * b4); + dst->vals[2][2] = (float)(+b0); + + for (int r = 0; r < 3; ++r) for (int c = 0; c < 3; ++c) { - if (!isfinitef_(dst->vals[r][c])) { - return false; - } + if (!isfinitef_(dst->vals[r][c])) { + return false; + } } - return true; + return true; } static Matrix3x3 Matrix3x3_concat(const Matrix3x3* A, const Matrix3x3* B) { - Matrix3x3 m = { { { 0,0,0 },{ 0,0,0 },{ 0,0,0 } } }; - for (int r = 0; r < 3; r++) - for (int c = 0; c < 3; c++) { - m.vals[r][c] = A->vals[r][0] * B->vals[0][c] - + A->vals[r][1] * B->vals[1][c] - + A->vals[r][2] * B->vals[2][c]; - } - return m; + Matrix3x3 m = {{{0, 0, 0}, {0, 0, 0}, {0, 0, 0}}}; + for (int r = 0; r < 3; r++) + for (int c = 0; c < 3; c++) { + m.vals[r][c] = A->vals[r][0] * B->vals[0][c] + A->vals[r][1] * B->vals[1][c] + + A->vals[r][2] * B->vals[2][c]; + } + return m; } static void float_XYZD50_to_grid16_lab(const float* xyz_float, uint8_t* grid16_lab) { - float v[3] = { - xyz_float[0] / kD50_x, - xyz_float[1] / kD50_y, - xyz_float[2] / kD50_z, - }; - for (size_t i = 0; i < 3; ++i) { - v[i] = v[i] > 0.008856f ? cbrtf(v[i]) : v[i] * 7.787f + (16 / 116.0f); - } - const float L = v[1] * 116.0f - 16.0f; - const float a = (v[0] - v[1]) * 500.0f; - const float b = (v[1] - v[2]) * 200.0f; - const float Lab_unorm[3] = { - L * (1 / 100.f), - (a + 128.0f) * (1 / 255.0f), - (b + 128.0f) * (1 / 255.0f), - }; - // This will encode L=1 as 0xFFFF. This matches how skcms will interpret the - // table, but the spec appears to indicate that the value should be 0xFF00. - // https://crbug.com/skia/13807 - for (size_t i = 0; i < 3; ++i) { - reinterpret_cast<uint16_t*>(grid16_lab)[i] = - Endian_SwapBE16(float_round_to_unorm16(Lab_unorm[i])); - } + float v[3] = { + xyz_float[0] / kD50_x, + xyz_float[1] / kD50_y, + xyz_float[2] / kD50_z, + }; + for (size_t i = 0; i < 3; ++i) { + v[i] = v[i] > 0.008856f ? cbrtf(v[i]) : v[i] * 7.787f + (16 / 116.0f); + } + const float L = v[1] * 116.0f - 16.0f; + const float a = (v[0] - v[1]) * 500.0f; + const float b = (v[1] - v[2]) * 200.0f; + const float Lab_unorm[3] = { + L * (1 / 100.f), + (a + 128.0f) * (1 / 255.0f), + (b + 128.0f) * (1 / 255.0f), + }; + // This will encode L=1 as 0xFFFF. This matches how skcms will interpret the + // table, but the spec appears to indicate that the value should be 0xFF00. + // https://crbug.com/skia/13807 + for (size_t i = 0; i < 3; ++i) { + reinterpret_cast<uint16_t*>(grid16_lab)[i] = + Endian_SwapBE16(float_round_to_unorm16(Lab_unorm[i])); + } } std::string IccHelper::get_desc_string(const ultrahdr_transfer_function tf, const ultrahdr_color_gamut gamut) { - std::string result; - switch (gamut) { - case ULTRAHDR_COLORGAMUT_BT709: - result += "sRGB"; - break; - case ULTRAHDR_COLORGAMUT_P3: - result += "Display P3"; - break; - case ULTRAHDR_COLORGAMUT_BT2100: - result += "Rec2020"; - break; - default: - result += "Unknown"; - break; - } - result += " Gamut with "; - switch (tf) { - case ULTRAHDR_TF_SRGB: - result += "sRGB"; - break; - case ULTRAHDR_TF_LINEAR: - result += "Linear"; - break; - case ULTRAHDR_TF_PQ: - result += "PQ"; - break; - case ULTRAHDR_TF_HLG: - result += "HLG"; - break; - default: - result += "Unknown"; - break; - } - result += " Transfer"; - return result; + std::string result; + switch (gamut) { + case ULTRAHDR_COLORGAMUT_BT709: + result += "sRGB"; + break; + case ULTRAHDR_COLORGAMUT_P3: + result += "Display P3"; + break; + case ULTRAHDR_COLORGAMUT_BT2100: + result += "Rec2020"; + break; + default: + result += "Unknown"; + break; + } + result += " Gamut with "; + switch (tf) { + case ULTRAHDR_TF_SRGB: + result += "sRGB"; + break; + case ULTRAHDR_TF_LINEAR: + result += "Linear"; + break; + case ULTRAHDR_TF_PQ: + result += "PQ"; + break; + case ULTRAHDR_TF_HLG: + result += "HLG"; + break; + default: + result += "Unknown"; + break; + } + result += " Transfer"; + return result; } std::shared_ptr<DataStruct> IccHelper::write_text_tag(const char* text) { - uint32_t text_length = strlen(text); - uint32_t header[] = { - Endian_SwapBE32(kTAG_TextType), // Type signature - 0, // Reserved - Endian_SwapBE32(1), // Number of records - Endian_SwapBE32(12), // Record size (must be 12) - Endian_SwapBE32(SetFourByteTag('e', 'n', 'U', 'S')), // English USA - Endian_SwapBE32(2 * text_length), // Length of string in bytes - Endian_SwapBE32(28), // Offset of string - }; - - uint32_t total_length = text_length * 2 + sizeof(header); - total_length = (((total_length + 2) >> 2) << 2); // 4 aligned - std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(total_length); - - if (!dataStruct->write(header, sizeof(header))) { - ALOGE("write_text_tag(): error in writing data"); - return dataStruct; - } + uint32_t text_length = strlen(text); + uint32_t header[] = { + Endian_SwapBE32(kTAG_TextType), // Type signature + 0, // Reserved + Endian_SwapBE32(1), // Number of records + Endian_SwapBE32(12), // Record size (must be 12) + Endian_SwapBE32(SetFourByteTag('e', 'n', 'U', 'S')), // English USA + Endian_SwapBE32(2 * text_length), // Length of string in bytes + Endian_SwapBE32(28), // Offset of string + }; + + uint32_t total_length = text_length * 2 + sizeof(header); + total_length = (((total_length + 2) >> 2) << 2); // 4 aligned + std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(total_length); + + if (!dataStruct->write(header, sizeof(header))) { + ALOGE("write_text_tag(): error in writing data"); + return dataStruct; + } - for (size_t i = 0; i < text_length; i++) { - // Convert ASCII to big-endian UTF-16. - dataStruct->write8(0); - dataStruct->write8(text[i]); - } + for (size_t i = 0; i < text_length; i++) { + // Convert ASCII to big-endian UTF-16. + dataStruct->write8(0); + dataStruct->write8(text[i]); + } - return dataStruct; + return dataStruct; } std::shared_ptr<DataStruct> IccHelper::write_xyz_tag(float x, float y, float z) { - uint32_t data[] = { - Endian_SwapBE32(kXYZ_PCSSpace), - 0, - static_cast<uint32_t>(Endian_SwapBE32(float_round_to_fixed(x))), - static_cast<uint32_t>(Endian_SwapBE32(float_round_to_fixed(y))), - static_cast<uint32_t>(Endian_SwapBE32(float_round_to_fixed(z))), - }; - std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(sizeof(data)); - dataStruct->write(&data, sizeof(data)); - return dataStruct; + uint32_t data[] = { + Endian_SwapBE32(kXYZ_PCSSpace), + 0, + static_cast<uint32_t>(Endian_SwapBE32(float_round_to_fixed(x))), + static_cast<uint32_t>(Endian_SwapBE32(float_round_to_fixed(y))), + static_cast<uint32_t>(Endian_SwapBE32(float_round_to_fixed(z))), + }; + std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(sizeof(data)); + dataStruct->write(&data, sizeof(data)); + return dataStruct; } std::shared_ptr<DataStruct> IccHelper::write_trc_tag(const int table_entries, const void* table_16) { - int total_length = 4 + 4 + 4 + table_entries * 2; - total_length = (((total_length + 2) >> 2) << 2); // 4 aligned - std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(total_length); - dataStruct->write32(Endian_SwapBE32(kTAG_CurveType)); // Type - dataStruct->write32(0); // Reserved - dataStruct->write32(Endian_SwapBE32(table_entries)); // Value count - for (int i = 0; i < table_entries; ++i) { - uint16_t value = reinterpret_cast<const uint16_t*>(table_16)[i]; - dataStruct->write16(value); - } - return dataStruct; + int total_length = 4 + 4 + 4 + table_entries * 2; + total_length = (((total_length + 2) >> 2) << 2); // 4 aligned + std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(total_length); + dataStruct->write32(Endian_SwapBE32(kTAG_CurveType)); // Type + dataStruct->write32(0); // Reserved + dataStruct->write32(Endian_SwapBE32(table_entries)); // Value count + for (int i = 0; i < table_entries; ++i) { + uint16_t value = reinterpret_cast<const uint16_t*>(table_16)[i]; + dataStruct->write16(value); + } + return dataStruct; } std::shared_ptr<DataStruct> IccHelper::write_trc_tag(const TransferFunction& fn) { - if (fn.a == 1.f && fn.b == 0.f && fn.c == 0.f - && fn.d == 0.f && fn.e == 0.f && fn.f == 0.f) { - int total_length = 16; - std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(total_length); - dataStruct->write32(Endian_SwapBE32(kTAG_ParaCurveType)); // Type - dataStruct->write32(0); // Reserved - dataStruct->write32(Endian_SwapBE16(kExponential_ParaCurveType)); - dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.g))); - return dataStruct; - } - - int total_length = 40; + if (fn.a == 1.f && fn.b == 0.f && fn.c == 0.f && fn.d == 0.f && fn.e == 0.f && fn.f == 0.f) { + int total_length = 16; std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(total_length); dataStruct->write32(Endian_SwapBE32(kTAG_ParaCurveType)); // Type dataStruct->write32(0); // Reserved - dataStruct->write32(Endian_SwapBE16(kGABCDEF_ParaCurveType)); + dataStruct->write32(Endian_SwapBE16(kExponential_ParaCurveType)); dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.g))); - dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.a))); - dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.b))); - dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.c))); - dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.d))); - dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.e))); - dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.f))); return dataStruct; + } + + int total_length = 40; + std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(total_length); + dataStruct->write32(Endian_SwapBE32(kTAG_ParaCurveType)); // Type + dataStruct->write32(0); // Reserved + dataStruct->write32(Endian_SwapBE16(kGABCDEF_ParaCurveType)); + dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.g))); + dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.a))); + dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.b))); + dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.c))); + dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.d))); + dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.e))); + dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.f))); + return dataStruct; } float IccHelper::compute_tone_map_gain(const ultrahdr_transfer_function tf, float L) { - if (L <= 0.f) { - return 1.f; - } - if (tf == ULTRAHDR_TF_PQ) { - // The PQ transfer function will map to the range [0, 1]. Linearly scale - // it up to the range [0, 10,000/203]. We will then tone map that back - // down to [0, 1]. - constexpr float kInputMaxLuminance = 10000 / 203.f; - constexpr float kOutputMaxLuminance = 1.0; - L *= kInputMaxLuminance; - - // Compute the tone map gain which will tone map from 10,000/203 to 1.0. - constexpr float kToneMapA = kOutputMaxLuminance / (kInputMaxLuminance * kInputMaxLuminance); - constexpr float kToneMapB = 1.f / kOutputMaxLuminance; - return kInputMaxLuminance * (1.f + kToneMapA * L) / (1.f + kToneMapB * L); - } - if (tf == ULTRAHDR_TF_HLG) { - // Let Lw be the brightness of the display in nits. - constexpr float Lw = 203.f; - const float gamma = 1.2f + 0.42f * std::log(Lw / 1000.f) / std::log(10.f); - return std::pow(L, gamma - 1.f); - } + if (L <= 0.f) { return 1.f; + } + if (tf == ULTRAHDR_TF_PQ) { + // The PQ transfer function will map to the range [0, 1]. Linearly scale + // it up to the range [0, 10,000/203]. We will then tone map that back + // down to [0, 1]. + constexpr float kInputMaxLuminance = 10000 / 203.f; + constexpr float kOutputMaxLuminance = 1.0; + L *= kInputMaxLuminance; + + // Compute the tone map gain which will tone map from 10,000/203 to 1.0. + constexpr float kToneMapA = kOutputMaxLuminance / (kInputMaxLuminance * kInputMaxLuminance); + constexpr float kToneMapB = 1.f / kOutputMaxLuminance; + return kInputMaxLuminance * (1.f + kToneMapA * L) / (1.f + kToneMapB * L); + } + if (tf == ULTRAHDR_TF_HLG) { + // Let Lw be the brightness of the display in nits. + constexpr float Lw = 203.f; + const float gamma = 1.2f + 0.42f * std::log(Lw / 1000.f) / std::log(10.f); + return std::pow(L, gamma - 1.f); + } + return 1.f; } std::shared_ptr<DataStruct> IccHelper::write_cicp_tag(uint32_t color_primaries, uint32_t transfer_characteristics) { - int total_length = 12; // 4 + 4 + 1 + 1 + 1 + 1 - std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(total_length); - dataStruct->write32(Endian_SwapBE32(kTAG_cicp)); // Type signature - dataStruct->write32(0); // Reserved - dataStruct->write8(color_primaries); // Color primaries - dataStruct->write8(transfer_characteristics); // Transfer characteristics - dataStruct->write8(0); // RGB matrix - dataStruct->write8(1); // Full range - return dataStruct; + int total_length = 12; // 4 + 4 + 1 + 1 + 1 + 1 + std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(total_length); + dataStruct->write32(Endian_SwapBE32(kTAG_cicp)); // Type signature + dataStruct->write32(0); // Reserved + dataStruct->write8(color_primaries); // Color primaries + dataStruct->write8(transfer_characteristics); // Transfer characteristics + dataStruct->write8(0); // RGB matrix + dataStruct->write8(1); // Full range + return dataStruct; } void IccHelper::compute_lut_entry(const Matrix3x3& src_to_XYZD50, float rgb[3]) { - // Compute the matrices to convert from source to Rec2020, and from Rec2020 to XYZD50. - Matrix3x3 src_to_rec2020; - const Matrix3x3 rec2020_to_XYZD50 = kRec2020; - { - Matrix3x3 XYZD50_to_rec2020; - Matrix3x3_invert(&rec2020_to_XYZD50, &XYZD50_to_rec2020); - src_to_rec2020 = Matrix3x3_concat(&XYZD50_to_rec2020, &src_to_XYZD50); - } - - // Convert the source signal to linear. - for (size_t i = 0; i < kNumChannels; ++i) { - rgb[i] = pqOetf(rgb[i]); - } - - // Convert source gamut to Rec2020. - Matrix3x3_apply(&src_to_rec2020, rgb); - - // Compute the luminance of the signal. - float L = bt2100Luminance({{{rgb[0], rgb[1], rgb[2]}}}); - - // Compute the tone map gain based on the luminance. - float tone_map_gain = compute_tone_map_gain(ULTRAHDR_TF_PQ, L); - - // Apply the tone map gain. - for (size_t i = 0; i < kNumChannels; ++i) { - rgb[i] *= tone_map_gain; - } - - // Convert from Rec2020-linear to XYZD50. - Matrix3x3_apply(&rec2020_to_XYZD50, rgb); + // Compute the matrices to convert from source to Rec2020, and from Rec2020 to XYZD50. + Matrix3x3 src_to_rec2020; + const Matrix3x3 rec2020_to_XYZD50 = kRec2020; + { + Matrix3x3 XYZD50_to_rec2020; + Matrix3x3_invert(&rec2020_to_XYZD50, &XYZD50_to_rec2020); + src_to_rec2020 = Matrix3x3_concat(&XYZD50_to_rec2020, &src_to_XYZD50); + } + + // Convert the source signal to linear. + for (size_t i = 0; i < kNumChannels; ++i) { + rgb[i] = pqOetf(rgb[i]); + } + + // Convert source gamut to Rec2020. + Matrix3x3_apply(&src_to_rec2020, rgb); + + // Compute the luminance of the signal. + float L = bt2100Luminance({{{rgb[0], rgb[1], rgb[2]}}}); + + // Compute the tone map gain based on the luminance. + float tone_map_gain = compute_tone_map_gain(ULTRAHDR_TF_PQ, L); + + // Apply the tone map gain. + for (size_t i = 0; i < kNumChannels; ++i) { + rgb[i] *= tone_map_gain; + } + + // Convert from Rec2020-linear to XYZD50. + Matrix3x3_apply(&rec2020_to_XYZD50, rgb); } std::shared_ptr<DataStruct> IccHelper::write_clut(const uint8_t* grid_points, const uint8_t* grid_16) { - uint32_t value_count = kNumChannels; - for (uint32_t i = 0; i < kNumChannels; ++i) { - value_count *= grid_points[i]; - } - - int total_length = 20 + 2 * value_count; - total_length = (((total_length + 2) >> 2) << 2); // 4 aligned - std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(total_length); - - for (size_t i = 0; i < 16; ++i) { - dataStruct->write8(i < kNumChannels ? grid_points[i] : 0); // Grid size - } - dataStruct->write8(2); // Grid byte width (always 16-bit) - dataStruct->write8(0); // Reserved - dataStruct->write8(0); // Reserved - dataStruct->write8(0); // Reserved - - for (uint32_t i = 0; i < value_count; ++i) { - uint16_t value = reinterpret_cast<const uint16_t*>(grid_16)[i]; - dataStruct->write16(value); - } - - return dataStruct; + uint32_t value_count = kNumChannels; + for (uint32_t i = 0; i < kNumChannels; ++i) { + value_count *= grid_points[i]; + } + + int total_length = 20 + 2 * value_count; + total_length = (((total_length + 2) >> 2) << 2); // 4 aligned + std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(total_length); + + for (size_t i = 0; i < 16; ++i) { + dataStruct->write8(i < kNumChannels ? grid_points[i] : 0); // Grid size + } + dataStruct->write8(2); // Grid byte width (always 16-bit) + dataStruct->write8(0); // Reserved + dataStruct->write8(0); // Reserved + dataStruct->write8(0); // Reserved + + for (uint32_t i = 0; i < value_count; ++i) { + uint16_t value = reinterpret_cast<const uint16_t*>(grid_16)[i]; + dataStruct->write16(value); + } + + return dataStruct; } std::shared_ptr<DataStruct> IccHelper::write_mAB_or_mBA_tag(uint32_t type, bool has_a_curves, const uint8_t* grid_points, const uint8_t* grid_16) { - const size_t b_curves_offset = 32; - std::shared_ptr<DataStruct> b_curves_data[kNumChannels]; - std::shared_ptr<DataStruct> a_curves_data[kNumChannels]; - size_t clut_offset = 0; - std::shared_ptr<DataStruct> clut; - size_t a_curves_offset = 0; - - // The "B" curve is required. + const size_t b_curves_offset = 32; + std::shared_ptr<DataStruct> b_curves_data[kNumChannels]; + std::shared_ptr<DataStruct> a_curves_data[kNumChannels]; + size_t clut_offset = 0; + std::shared_ptr<DataStruct> clut; + size_t a_curves_offset = 0; + + // The "B" curve is required. + for (size_t i = 0; i < kNumChannels; ++i) { + b_curves_data[i] = write_trc_tag(kLinear_TransFun); + } + + // The "A" curve and CLUT are optional. + if (has_a_curves) { + clut_offset = b_curves_offset; for (size_t i = 0; i < kNumChannels; ++i) { - b_curves_data[i] = write_trc_tag(kLinear_TransFun); + clut_offset += b_curves_data[i]->getLength(); } + clut = write_clut(grid_points, grid_16); - // The "A" curve and CLUT are optional. - if (has_a_curves) { - clut_offset = b_curves_offset; - for (size_t i = 0; i < kNumChannels; ++i) { - clut_offset += b_curves_data[i]->getLength(); - } - clut = write_clut(grid_points, grid_16); - - a_curves_offset = clut_offset + clut->getLength(); - for (size_t i = 0; i < kNumChannels; ++i) { - a_curves_data[i] = write_trc_tag(kLinear_TransFun); - } + a_curves_offset = clut_offset + clut->getLength(); + for (size_t i = 0; i < kNumChannels; ++i) { + a_curves_data[i] = write_trc_tag(kLinear_TransFun); } + } - int total_length = b_curves_offset; + int total_length = b_curves_offset; + for (size_t i = 0; i < kNumChannels; ++i) { + total_length += b_curves_data[i]->getLength(); + } + if (has_a_curves) { + total_length += clut->getLength(); for (size_t i = 0; i < kNumChannels; ++i) { - total_length += b_curves_data[i]->getLength(); - } - if (has_a_curves) { - total_length += clut->getLength(); - for (size_t i = 0; i < kNumChannels; ++i) { - total_length += a_curves_data[i]->getLength(); - } - } - std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(total_length); - dataStruct->write32(Endian_SwapBE32(type)); // Type signature - dataStruct->write32(0); // Reserved - dataStruct->write8(kNumChannels); // Input channels - dataStruct->write8(kNumChannels); // Output channels - dataStruct->write16(0); // Reserved - dataStruct->write32(Endian_SwapBE32(b_curves_offset)); // B curve offset - dataStruct->write32(Endian_SwapBE32(0)); // Matrix offset (ignored) - dataStruct->write32(Endian_SwapBE32(0)); // M curve offset (ignored) - dataStruct->write32(Endian_SwapBE32(clut_offset)); // CLUT offset - dataStruct->write32(Endian_SwapBE32(a_curves_offset)); // A curve offset + total_length += a_curves_data[i]->getLength(); + } + } + std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(total_length); + dataStruct->write32(Endian_SwapBE32(type)); // Type signature + dataStruct->write32(0); // Reserved + dataStruct->write8(kNumChannels); // Input channels + dataStruct->write8(kNumChannels); // Output channels + dataStruct->write16(0); // Reserved + dataStruct->write32(Endian_SwapBE32(b_curves_offset)); // B curve offset + dataStruct->write32(Endian_SwapBE32(0)); // Matrix offset (ignored) + dataStruct->write32(Endian_SwapBE32(0)); // M curve offset (ignored) + dataStruct->write32(Endian_SwapBE32(clut_offset)); // CLUT offset + dataStruct->write32(Endian_SwapBE32(a_curves_offset)); // A curve offset + for (size_t i = 0; i < kNumChannels; ++i) { + if (dataStruct->write(b_curves_data[i]->getData(), b_curves_data[i]->getLength())) { + return dataStruct; + } + } + if (has_a_curves) { + dataStruct->write(clut->getData(), clut->getLength()); for (size_t i = 0; i < kNumChannels; ++i) { - if (dataStruct->write(b_curves_data[i]->getData(), b_curves_data[i]->getLength())) { - return dataStruct; - } - } - if (has_a_curves) { - dataStruct->write(clut->getData(), clut->getLength()); - for (size_t i = 0; i < kNumChannels; ++i) { - dataStruct->write(a_curves_data[i]->getData(), a_curves_data[i]->getLength()); - } + dataStruct->write(a_curves_data[i]->getData(), a_curves_data[i]->getLength()); } - return dataStruct; + } + return dataStruct; } std::shared_ptr<DataStruct> IccHelper::writeIccProfile(ultrahdr_transfer_function tf, ultrahdr_color_gamut gamut) { - ICCHeader header; - - std::vector<std::pair<uint32_t, std::shared_ptr<DataStruct>>> tags; - - // Compute profile description tag - std::string desc = get_desc_string(tf, gamut); - - tags.emplace_back(kTAG_desc, write_text_tag(desc.c_str())); - - Matrix3x3 toXYZD50; - switch (gamut) { - case ULTRAHDR_COLORGAMUT_BT709: - toXYZD50 = kSRGB; - break; - case ULTRAHDR_COLORGAMUT_P3: - toXYZD50 = kDisplayP3; - break; - case ULTRAHDR_COLORGAMUT_BT2100: - toXYZD50 = kRec2020; - break; - default: - // Should not fall here. - return nullptr; - } - - // Compute primaries. - { - tags.emplace_back(kTAG_rXYZ, - write_xyz_tag(toXYZD50.vals[0][0], toXYZD50.vals[1][0], toXYZD50.vals[2][0])); - tags.emplace_back(kTAG_gXYZ, - write_xyz_tag(toXYZD50.vals[0][1], toXYZD50.vals[1][1], toXYZD50.vals[2][1])); - tags.emplace_back(kTAG_bXYZ, - write_xyz_tag(toXYZD50.vals[0][2], toXYZD50.vals[1][2], toXYZD50.vals[2][2])); - } - - // Compute white point tag (must be D50) - tags.emplace_back(kTAG_wtpt, write_xyz_tag(kD50_x, kD50_y, kD50_z)); - - // Compute transfer curves. - if (tf != ULTRAHDR_TF_PQ) { - if (tf == ULTRAHDR_TF_HLG) { - std::vector<uint8_t> trc_table; - trc_table.resize(kTrcTableSize * 2); - for (uint32_t i = 0; i < kTrcTableSize; ++i) { - float x = i / (kTrcTableSize - 1.f); - float y = hlgOetf(x); - y *= compute_tone_map_gain(tf, y); - float_to_table16(y, &trc_table[2 * i]); - } - - tags.emplace_back(kTAG_rTRC, - write_trc_tag(kTrcTableSize, reinterpret_cast<uint8_t*>(trc_table.data()))); - tags.emplace_back(kTAG_gTRC, - write_trc_tag(kTrcTableSize, reinterpret_cast<uint8_t*>(trc_table.data()))); - tags.emplace_back(kTAG_bTRC, - write_trc_tag(kTrcTableSize, reinterpret_cast<uint8_t*>(trc_table.data()))); - } else { - tags.emplace_back(kTAG_rTRC, write_trc_tag(kSRGB_TransFun)); - tags.emplace_back(kTAG_gTRC, write_trc_tag(kSRGB_TransFun)); - tags.emplace_back(kTAG_bTRC, write_trc_tag(kSRGB_TransFun)); - } - } - - // Compute CICP. - if (tf == ULTRAHDR_TF_HLG || tf == ULTRAHDR_TF_PQ) { - // The CICP tag is present in ICC 4.4, so update the header's version. - header.version = Endian_SwapBE32(0x04400000); - - uint32_t color_primaries = 0; - if (gamut == ULTRAHDR_COLORGAMUT_BT709) { - color_primaries = kCICPPrimariesSRGB; - } else if (gamut == ULTRAHDR_COLORGAMUT_P3) { - color_primaries = kCICPPrimariesP3; - } - - uint32_t transfer_characteristics = 0; - if (tf == ULTRAHDR_TF_SRGB) { - transfer_characteristics = kCICPTrfnSRGB; - } else if (tf == ULTRAHDR_TF_LINEAR) { - transfer_characteristics = kCICPTrfnLinear; - } else if (tf == ULTRAHDR_TF_PQ) { - transfer_characteristics = kCICPTrfnPQ; - } else if (tf == ULTRAHDR_TF_HLG) { - transfer_characteristics = kCICPTrfnHLG; - } - tags.emplace_back(kTAG_cicp, write_cicp_tag(color_primaries, transfer_characteristics)); - } - - // Compute A2B0. - if (tf == ULTRAHDR_TF_PQ) { - std::vector<uint8_t> a2b_grid; - a2b_grid.resize(kGridSize * kGridSize * kGridSize * kNumChannels * 2); - size_t a2b_grid_index = 0; - for (uint32_t r_index = 0; r_index < kGridSize; ++r_index) { - for (uint32_t g_index = 0; g_index < kGridSize; ++g_index) { - for (uint32_t b_index = 0; b_index < kGridSize; ++b_index) { - float rgb[3] = { - r_index / (kGridSize - 1.f), - g_index / (kGridSize - 1.f), - b_index / (kGridSize - 1.f), - }; - compute_lut_entry(toXYZD50, rgb); - float_XYZD50_to_grid16_lab(rgb, &a2b_grid[a2b_grid_index]); - a2b_grid_index += 6; - } - } - } - const uint8_t* grid_16 = reinterpret_cast<const uint8_t*>(a2b_grid.data()); - - uint8_t grid_points[kNumChannels]; - for (size_t i = 0; i < kNumChannels; ++i) { - grid_points[i] = kGridSize; + ICCHeader header; + + std::vector<std::pair<uint32_t, std::shared_ptr<DataStruct>>> tags; + + // Compute profile description tag + std::string desc = get_desc_string(tf, gamut); + + tags.emplace_back(kTAG_desc, write_text_tag(desc.c_str())); + + Matrix3x3 toXYZD50; + switch (gamut) { + case ULTRAHDR_COLORGAMUT_BT709: + toXYZD50 = kSRGB; + break; + case ULTRAHDR_COLORGAMUT_P3: + toXYZD50 = kDisplayP3; + break; + case ULTRAHDR_COLORGAMUT_BT2100: + toXYZD50 = kRec2020; + break; + default: + // Should not fall here. + return nullptr; + } + + // Compute primaries. + { + tags.emplace_back(kTAG_rXYZ, + write_xyz_tag(toXYZD50.vals[0][0], toXYZD50.vals[1][0], toXYZD50.vals[2][0])); + tags.emplace_back(kTAG_gXYZ, + write_xyz_tag(toXYZD50.vals[0][1], toXYZD50.vals[1][1], toXYZD50.vals[2][1])); + tags.emplace_back(kTAG_bXYZ, + write_xyz_tag(toXYZD50.vals[0][2], toXYZD50.vals[1][2], toXYZD50.vals[2][2])); + } + + // Compute white point tag (must be D50) + tags.emplace_back(kTAG_wtpt, write_xyz_tag(kD50_x, kD50_y, kD50_z)); + + // Compute transfer curves. + if (tf != ULTRAHDR_TF_PQ) { + if (tf == ULTRAHDR_TF_HLG) { + std::vector<uint8_t> trc_table; + trc_table.resize(kTrcTableSize * 2); + for (uint32_t i = 0; i < kTrcTableSize; ++i) { + float x = i / (kTrcTableSize - 1.f); + float y = hlgOetf(x); + y *= compute_tone_map_gain(tf, y); + float_to_table16(y, &trc_table[2 * i]); + } + + tags.emplace_back(kTAG_rTRC, + write_trc_tag(kTrcTableSize, reinterpret_cast<uint8_t*>(trc_table.data()))); + tags.emplace_back(kTAG_gTRC, + write_trc_tag(kTrcTableSize, reinterpret_cast<uint8_t*>(trc_table.data()))); + tags.emplace_back(kTAG_bTRC, + write_trc_tag(kTrcTableSize, reinterpret_cast<uint8_t*>(trc_table.data()))); + } else { + tags.emplace_back(kTAG_rTRC, write_trc_tag(kSRGB_TransFun)); + tags.emplace_back(kTAG_gTRC, write_trc_tag(kSRGB_TransFun)); + tags.emplace_back(kTAG_bTRC, write_trc_tag(kSRGB_TransFun)); + } + } + + // Compute CICP. + if (tf == ULTRAHDR_TF_HLG || tf == ULTRAHDR_TF_PQ) { + // The CICP tag is present in ICC 4.4, so update the header's version. + header.version = Endian_SwapBE32(0x04400000); + + uint32_t color_primaries = 0; + if (gamut == ULTRAHDR_COLORGAMUT_BT709) { + color_primaries = kCICPPrimariesSRGB; + } else if (gamut == ULTRAHDR_COLORGAMUT_P3) { + color_primaries = kCICPPrimariesP3; + } + + uint32_t transfer_characteristics = 0; + if (tf == ULTRAHDR_TF_SRGB) { + transfer_characteristics = kCICPTrfnSRGB; + } else if (tf == ULTRAHDR_TF_LINEAR) { + transfer_characteristics = kCICPTrfnLinear; + } else if (tf == ULTRAHDR_TF_PQ) { + transfer_characteristics = kCICPTrfnPQ; + } else if (tf == ULTRAHDR_TF_HLG) { + transfer_characteristics = kCICPTrfnHLG; + } + tags.emplace_back(kTAG_cicp, write_cicp_tag(color_primaries, transfer_characteristics)); + } + + // Compute A2B0. + if (tf == ULTRAHDR_TF_PQ) { + std::vector<uint8_t> a2b_grid; + a2b_grid.resize(kGridSize * kGridSize * kGridSize * kNumChannels * 2); + size_t a2b_grid_index = 0; + for (uint32_t r_index = 0; r_index < kGridSize; ++r_index) { + for (uint32_t g_index = 0; g_index < kGridSize; ++g_index) { + for (uint32_t b_index = 0; b_index < kGridSize; ++b_index) { + float rgb[3] = { + r_index / (kGridSize - 1.f), + g_index / (kGridSize - 1.f), + b_index / (kGridSize - 1.f), + }; + compute_lut_entry(toXYZD50, rgb); + float_XYZD50_to_grid16_lab(rgb, &a2b_grid[a2b_grid_index]); + a2b_grid_index += 6; } - - auto a2b_data = write_mAB_or_mBA_tag(kTAG_mABType, - /* has_a_curves */ true, - grid_points, - grid_16); - tags.emplace_back(kTAG_A2B0, std::move(a2b_data)); + } } + const uint8_t* grid_16 = reinterpret_cast<const uint8_t*>(a2b_grid.data()); - // Compute B2A0. - if (tf == ULTRAHDR_TF_PQ) { - auto b2a_data = write_mAB_or_mBA_tag(kTAG_mBAType, - /* has_a_curves */ false, - /* grid_points */ nullptr, - /* grid_16 */ nullptr); - tags.emplace_back(kTAG_B2A0, std::move(b2a_data)); - } - - // Compute copyright tag - tags.emplace_back(kTAG_cprt, write_text_tag("Google Inc. 2022")); - - // Compute the size of the profile. - size_t tag_data_size = 0; - for (const auto& tag : tags) { - tag_data_size += tag.second->getLength(); - } - size_t tag_table_size = kICCTagTableEntrySize * tags.size(); - size_t profile_size = kICCHeaderSize + tag_table_size + tag_data_size; - - std::shared_ptr<DataStruct> dataStruct = - std::make_shared<DataStruct>(profile_size + kICCIdentifierSize); - - // Write identifier, chunk count, and chunk ID - if (!dataStruct->write(kICCIdentifier, sizeof(kICCIdentifier)) || - !dataStruct->write8(1) || !dataStruct->write8(1)) { - ALOGE("writeIccProfile(): error in identifier"); - return dataStruct; - } - - // Write the header. - header.data_color_space = Endian_SwapBE32(Signature_RGB); - header.pcs = Endian_SwapBE32(tf == ULTRAHDR_TF_PQ ? Signature_Lab : Signature_XYZ); - header.size = Endian_SwapBE32(profile_size); - header.tag_count = Endian_SwapBE32(tags.size()); + uint8_t grid_points[kNumChannels]; + for (size_t i = 0; i < kNumChannels; ++i) { + grid_points[i] = kGridSize; + } + + auto a2b_data = write_mAB_or_mBA_tag(kTAG_mABType, + /* has_a_curves */ true, grid_points, grid_16); + tags.emplace_back(kTAG_A2B0, std::move(a2b_data)); + } + + // Compute B2A0. + if (tf == ULTRAHDR_TF_PQ) { + auto b2a_data = write_mAB_or_mBA_tag(kTAG_mBAType, + /* has_a_curves */ false, + /* grid_points */ nullptr, + /* grid_16 */ nullptr); + tags.emplace_back(kTAG_B2A0, std::move(b2a_data)); + } + + // Compute copyright tag + tags.emplace_back(kTAG_cprt, write_text_tag("Google Inc. 2022")); + + // Compute the size of the profile. + size_t tag_data_size = 0; + for (const auto& tag : tags) { + tag_data_size += tag.second->getLength(); + } + size_t tag_table_size = kICCTagTableEntrySize * tags.size(); + size_t profile_size = kICCHeaderSize + tag_table_size + tag_data_size; + + std::shared_ptr<DataStruct> dataStruct = + std::make_shared<DataStruct>(profile_size + kICCIdentifierSize); + + // Write identifier, chunk count, and chunk ID + if (!dataStruct->write(kICCIdentifier, sizeof(kICCIdentifier)) || !dataStruct->write8(1) || + !dataStruct->write8(1)) { + ALOGE("writeIccProfile(): error in identifier"); + return dataStruct; + } - if (!dataStruct->write(&header, sizeof(header))) { - ALOGE("writeIccProfile(): error in header"); - return dataStruct; - } + // Write the header. + header.data_color_space = Endian_SwapBE32(Signature_RGB); + header.pcs = Endian_SwapBE32(tf == ULTRAHDR_TF_PQ ? Signature_Lab : Signature_XYZ); + header.size = Endian_SwapBE32(profile_size); + header.tag_count = Endian_SwapBE32(tags.size()); - // Write the tag table. Track the offset and size of the previous tag to - // compute each tag's offset. An empty SkData indicates that the previous - // tag is to be reused. - uint32_t last_tag_offset = sizeof(header) + tag_table_size; - uint32_t last_tag_size = 0; - for (const auto& tag : tags) { - last_tag_offset = last_tag_offset + last_tag_size; - last_tag_size = tag.second->getLength(); - uint32_t tag_table_entry[3] = { - Endian_SwapBE32(tag.first), - Endian_SwapBE32(last_tag_offset), - Endian_SwapBE32(last_tag_size), - }; - if (!dataStruct->write(tag_table_entry, sizeof(tag_table_entry))) { - ALOGE("writeIccProfile(): error in writing tag table"); - return dataStruct; - } + if (!dataStruct->write(&header, sizeof(header))) { + ALOGE("writeIccProfile(): error in header"); + return dataStruct; + } + + // Write the tag table. Track the offset and size of the previous tag to + // compute each tag's offset. An empty SkData indicates that the previous + // tag is to be reused. + uint32_t last_tag_offset = sizeof(header) + tag_table_size; + uint32_t last_tag_size = 0; + for (const auto& tag : tags) { + last_tag_offset = last_tag_offset + last_tag_size; + last_tag_size = tag.second->getLength(); + uint32_t tag_table_entry[3] = { + Endian_SwapBE32(tag.first), + Endian_SwapBE32(last_tag_offset), + Endian_SwapBE32(last_tag_size), + }; + if (!dataStruct->write(tag_table_entry, sizeof(tag_table_entry))) { + ALOGE("writeIccProfile(): error in writing tag table"); + return dataStruct; } + } - // Write the tags. - for (const auto& tag : tags) { - if (!dataStruct->write(tag.second->getData(), tag.second->getLength())) { - ALOGE("writeIccProfile(): error in writing tags"); - return dataStruct; - } + // Write the tags. + for (const auto& tag : tags) { + if (!dataStruct->write(tag.second->getData(), tag.second->getLength())) { + ALOGE("writeIccProfile(): error in writing tags"); + return dataStruct; } + } - return dataStruct; + return dataStruct; } -bool IccHelper::tagsEqualToMatrix(const Matrix3x3& matrix, - const uint8_t* red_tag, - const uint8_t* green_tag, - const uint8_t* blue_tag) { - std::shared_ptr<DataStruct> red_tag_test = - write_xyz_tag(matrix.vals[0][0], matrix.vals[1][0], matrix.vals[2][0]); - std::shared_ptr<DataStruct> green_tag_test = - write_xyz_tag(matrix.vals[0][1], matrix.vals[1][1], matrix.vals[2][1]); - std::shared_ptr<DataStruct> blue_tag_test = - write_xyz_tag(matrix.vals[0][2], matrix.vals[1][2], matrix.vals[2][2]); - return memcmp(red_tag, red_tag_test->getData(), kColorantTagSize) == 0 && - memcmp(green_tag, green_tag_test->getData(), kColorantTagSize) == 0 && - memcmp(blue_tag, blue_tag_test->getData(), kColorantTagSize) == 0; +bool IccHelper::tagsEqualToMatrix(const Matrix3x3& matrix, const uint8_t* red_tag, + const uint8_t* green_tag, const uint8_t* blue_tag) { + std::shared_ptr<DataStruct> red_tag_test = + write_xyz_tag(matrix.vals[0][0], matrix.vals[1][0], matrix.vals[2][0]); + std::shared_ptr<DataStruct> green_tag_test = + write_xyz_tag(matrix.vals[0][1], matrix.vals[1][1], matrix.vals[2][1]); + std::shared_ptr<DataStruct> blue_tag_test = + write_xyz_tag(matrix.vals[0][2], matrix.vals[1][2], matrix.vals[2][2]); + return memcmp(red_tag, red_tag_test->getData(), kColorantTagSize) == 0 && + memcmp(green_tag, green_tag_test->getData(), kColorantTagSize) == 0 && + memcmp(blue_tag, blue_tag_test->getData(), kColorantTagSize) == 0; } ultrahdr_color_gamut IccHelper::readIccColorGamut(void* icc_data, size_t icc_size) { - // Each tag table entry consists of 3 fields of 4 bytes each. - static const size_t kTagTableEntrySize = 12; - - if (icc_data == nullptr || icc_size < sizeof(ICCHeader) + kICCIdentifierSize) { - return ULTRAHDR_COLORGAMUT_UNSPECIFIED; - } - - if (memcmp(icc_data, kICCIdentifier, sizeof(kICCIdentifier)) != 0) { - return ULTRAHDR_COLORGAMUT_UNSPECIFIED; - } - - uint8_t* icc_bytes = reinterpret_cast<uint8_t*>(icc_data) + kICCIdentifierSize; - - ICCHeader* header = reinterpret_cast<ICCHeader*>(icc_bytes); - - // Use 0 to indicate not found, since offsets are always relative to start - // of ICC data and therefore a tag offset of zero would never be valid. - size_t red_primary_offset = 0, green_primary_offset = 0, blue_primary_offset = 0; - size_t red_primary_size = 0, green_primary_size = 0, blue_primary_size = 0; - for (size_t tag_idx = 0; tag_idx < Endian_SwapBE32(header->tag_count); ++tag_idx) { - uint32_t* tag_entry_start = reinterpret_cast<uint32_t*>( - icc_bytes + sizeof(ICCHeader) + tag_idx * kTagTableEntrySize); - // first 4 bytes are the tag signature, next 4 bytes are the tag offset, - // last 4 bytes are the tag length in bytes. - if (red_primary_offset == 0 && *tag_entry_start == Endian_SwapBE32(kTAG_rXYZ)) { - red_primary_offset = Endian_SwapBE32(*(tag_entry_start+1)); - red_primary_size = Endian_SwapBE32(*(tag_entry_start+2)); - } else if (green_primary_offset == 0 && *tag_entry_start == Endian_SwapBE32(kTAG_gXYZ)) { - green_primary_offset = Endian_SwapBE32(*(tag_entry_start+1)); - green_primary_size = Endian_SwapBE32(*(tag_entry_start+2)); - } else if (blue_primary_offset == 0 && *tag_entry_start == Endian_SwapBE32(kTAG_bXYZ)) { - blue_primary_offset = Endian_SwapBE32(*(tag_entry_start+1)); - blue_primary_size = Endian_SwapBE32(*(tag_entry_start+2)); - } - } - - if (red_primary_offset == 0 || red_primary_size != kColorantTagSize || - kICCIdentifierSize + red_primary_offset + red_primary_size > icc_size || - green_primary_offset == 0 || green_primary_size != kColorantTagSize || - kICCIdentifierSize + green_primary_offset + green_primary_size > icc_size || - blue_primary_offset == 0 || blue_primary_size != kColorantTagSize || - kICCIdentifierSize + blue_primary_offset + blue_primary_size > icc_size) { - return ULTRAHDR_COLORGAMUT_UNSPECIFIED; - } + // Each tag table entry consists of 3 fields of 4 bytes each. + static const size_t kTagTableEntrySize = 12; - uint8_t* red_tag = icc_bytes + red_primary_offset; - uint8_t* green_tag = icc_bytes + green_primary_offset; - uint8_t* blue_tag = icc_bytes + blue_primary_offset; - - // Serialize tags as we do on encode and compare what we find to that to - // determine the gamut (since we don't have a need yet for full deserialize). - if (tagsEqualToMatrix(kSRGB, red_tag, green_tag, blue_tag)) { - return ULTRAHDR_COLORGAMUT_BT709; - } else if (tagsEqualToMatrix(kDisplayP3, red_tag, green_tag, blue_tag)) { - return ULTRAHDR_COLORGAMUT_P3; - } else if (tagsEqualToMatrix(kRec2020, red_tag, green_tag, blue_tag)) { - return ULTRAHDR_COLORGAMUT_BT2100; - } + if (icc_data == nullptr || icc_size < sizeof(ICCHeader) + kICCIdentifierSize) { + return ULTRAHDR_COLORGAMUT_UNSPECIFIED; + } - // Didn't find a match to one of the profiles we write; indicate the gamut - // is unspecified since we don't understand it. + if (memcmp(icc_data, kICCIdentifier, sizeof(kICCIdentifier)) != 0) { + return ULTRAHDR_COLORGAMUT_UNSPECIFIED; + } + + uint8_t* icc_bytes = reinterpret_cast<uint8_t*>(icc_data) + kICCIdentifierSize; + + ICCHeader* header = reinterpret_cast<ICCHeader*>(icc_bytes); + + // Use 0 to indicate not found, since offsets are always relative to start + // of ICC data and therefore a tag offset of zero would never be valid. + size_t red_primary_offset = 0, green_primary_offset = 0, blue_primary_offset = 0; + size_t red_primary_size = 0, green_primary_size = 0, blue_primary_size = 0; + for (size_t tag_idx = 0; tag_idx < Endian_SwapBE32(header->tag_count); ++tag_idx) { + uint32_t* tag_entry_start = + reinterpret_cast<uint32_t*>(icc_bytes + sizeof(ICCHeader) + tag_idx * kTagTableEntrySize); + // first 4 bytes are the tag signature, next 4 bytes are the tag offset, + // last 4 bytes are the tag length in bytes. + if (red_primary_offset == 0 && *tag_entry_start == Endian_SwapBE32(kTAG_rXYZ)) { + red_primary_offset = Endian_SwapBE32(*(tag_entry_start + 1)); + red_primary_size = Endian_SwapBE32(*(tag_entry_start + 2)); + } else if (green_primary_offset == 0 && *tag_entry_start == Endian_SwapBE32(kTAG_gXYZ)) { + green_primary_offset = Endian_SwapBE32(*(tag_entry_start + 1)); + green_primary_size = Endian_SwapBE32(*(tag_entry_start + 2)); + } else if (blue_primary_offset == 0 && *tag_entry_start == Endian_SwapBE32(kTAG_bXYZ)) { + blue_primary_offset = Endian_SwapBE32(*(tag_entry_start + 1)); + blue_primary_size = Endian_SwapBE32(*(tag_entry_start + 2)); + } + } + + if (red_primary_offset == 0 || red_primary_size != kColorantTagSize || + kICCIdentifierSize + red_primary_offset + red_primary_size > icc_size || + green_primary_offset == 0 || green_primary_size != kColorantTagSize || + kICCIdentifierSize + green_primary_offset + green_primary_size > icc_size || + blue_primary_offset == 0 || blue_primary_size != kColorantTagSize || + kICCIdentifierSize + blue_primary_offset + blue_primary_size > icc_size) { return ULTRAHDR_COLORGAMUT_UNSPECIFIED; + } + + uint8_t* red_tag = icc_bytes + red_primary_offset; + uint8_t* green_tag = icc_bytes + green_primary_offset; + uint8_t* blue_tag = icc_bytes + blue_primary_offset; + + // Serialize tags as we do on encode and compare what we find to that to + // determine the gamut (since we don't have a need yet for full deserialize). + if (tagsEqualToMatrix(kSRGB, red_tag, green_tag, blue_tag)) { + return ULTRAHDR_COLORGAMUT_BT709; + } else if (tagsEqualToMatrix(kDisplayP3, red_tag, green_tag, blue_tag)) { + return ULTRAHDR_COLORGAMUT_P3; + } else if (tagsEqualToMatrix(kRec2020, red_tag, green_tag, blue_tag)) { + return ULTRAHDR_COLORGAMUT_BT2100; + } + + // Didn't find a match to one of the profiles we write; indicate the gamut + // is unspecified since we don't understand it. + return ULTRAHDR_COLORGAMUT_UNSPECIFIED; } -} // namespace ultrahdr +} // namespace ultrahdr |