libultrahdr: correct srgb, p3 calculations and jpeg yuv handling
* Correct luminance calculation for sRGB to utilize actual luminance
coefficients for the gamut, rather than 601 luma coefficients.
* Correct YUV<->RGB conversion for sRGB to utilize Rec.709 coefficients
rather than Rec.601 coefficients as it was previously.
* New P3 YUV<->RGB conversion, which uses Rec.601 coefficients.
* Also ICC Profile fixes to make things work; more below.
* Update things to correctly convert to and from Rec.601 YUV for jpeg
encoding; more below.
This setup for YUV<->RGB coefficients is chosen to match the
expectations of DataSpace when it comes to interpretting YUV encoding of
data. Generally, the interpretation is cued off of the color primaries,
since the specifications around color primaries generally also specify a
YUV interpretation.
Display-P3 is a bit of an outlier; the best specification of Display-P3
is in SMPTE EG 432-1, but EG 432-1 doesn't cover YUV interpretation. So,
since DataSpace interprets Display-P3 YUV data via the Rec.601
coefficients, we should do the same here.
ICC Profile fixes; ICC profiles we wrote were broken before this for a
variety of reasons:
* The endianness macro wasn't actually swapping endiannesas to provide
the correct encoding in our output.
* We weren't writing out the identifier for the app segment, including
the chunk count and ID.
* We were assuming input JPEGs have ICC data, which may not be the case.
* We also need to read in the ICC profile during decode to apply the map
properly, and we didn't have any mechanism previously to read the ICC
profile and determine the gamut of the encoded JPEGR file.
* Upon adding ICC reading code to our JPEG decoding, also remove some
dead code from previous EXIF reading.
* Add a number of tests to verify all of this stuff stays fixed.
YUV interpretation and Rec.601:
* Previously, we were feeding YUV right into the JPEG encoder; this is
problematic because JPEG encoders usually (and definitely in our
specific case) expect Rec.601 YUV encoded input data, since this is by
definition the format of JPEG YUV data according to ECMA TR/98.
* Now properly convert from Rec.709 or Rec.2100 YUV encoding to Rec.601
(when necessary) prior to passing YUV data to the jpeg encoder.
* Also make sure we properly interpret decoded YUV output as Rec.601
after decode.
* This involved added some new methods to facilitate these conversions.
* Added some new tests to verify these conversions.
* Note that to do these YUV conversions for subsampled 420 data, we take
each set of 4 Y and 1 UV, and calculate the result against each
combination. The new Y values each get the corresponding result, and
the new UV value is equal to the average of the set.
* Note that none of this is a concern for gain map encoding/decoding via
JPEG because gain maps are single channel.
Bug: 283143961
Test: added new tests, all tests pass
Change-Id: Ibc7b1779fc3a8244f85abb581c554963f57dc5a4
diff --git a/libs/ultrahdr/tests/gainmapmath_test.cpp b/libs/ultrahdr/tests/gainmapmath_test.cpp
index c456653..af90365 100644
--- a/libs/ultrahdr/tests/gainmapmath_test.cpp
+++ b/libs/ultrahdr/tests/gainmapmath_test.cpp
@@ -28,6 +28,7 @@
float ComparisonEpsilon() { return 1e-4f; }
float LuminanceEpsilon() { return 1e-2f; }
+ float YuvConversionEpsilon() { return 1.0f / (255.0f * 2.0f); }
Color Yuv420(uint8_t y, uint8_t u, uint8_t v) {
return {{{ static_cast<float>(y) / 255.0f,
@@ -63,9 +64,13 @@
Color YuvBlack() { return {{{ 0.0f, 0.0f, 0.0f }}}; }
Color YuvWhite() { return {{{ 1.0f, 0.0f, 0.0f }}}; }
- Color SrgbYuvRed() { return {{{ 0.299f, -0.1687f, 0.5f }}}; }
- Color SrgbYuvGreen() { return {{{ 0.587f, -0.3313f, -0.4187f }}}; }
- Color SrgbYuvBlue() { return {{{ 0.114f, 0.5f, -0.0813f }}}; }
+ Color SrgbYuvRed() { return {{{ 0.2126f, -0.11457f, 0.5f }}}; }
+ Color SrgbYuvGreen() { return {{{ 0.7152f, -0.38543f, -0.45415f }}}; }
+ Color SrgbYuvBlue() { return {{{ 0.0722f, 0.5f, -0.04585f }}}; }
+
+ Color P3YuvRed() { return {{{ 0.299f, -0.16874f, 0.5f }}}; }
+ Color P3YuvGreen() { return {{{ 0.587f, -0.33126f, -0.41869f }}}; }
+ Color P3YuvBlue() { return {{{ 0.114f, 0.5f, -0.08131f }}}; }
Color Bt2100YuvRed() { return {{{ 0.2627f, -0.13963f, 0.5f }}}; }
Color Bt2100YuvGreen() { return {{{ 0.6780f, -0.36037f, -0.45979f }}}; }
@@ -78,6 +83,13 @@
return luminance_scaled * kSdrWhiteNits;
}
+ float P3YuvToLuminance(Color yuv_gamma, ColorCalculationFn luminanceFn) {
+ Color rgb_gamma = p3YuvToRgb(yuv_gamma);
+ Color rgb = srgbInvOetf(rgb_gamma);
+ float luminance_scaled = luminanceFn(rgb);
+ return luminance_scaled * kSdrWhiteNits;
+ }
+
float Bt2100YuvToLuminance(Color yuv_gamma, ColorTransformFn hdrInvOetf,
ColorTransformFn gamutConversionFn, ColorCalculationFn luminanceFn,
float scale_factor) {
@@ -402,6 +414,56 @@
EXPECT_FLOAT_EQ(p3Luminance(RgbBlue()), 0.06891f);
}
+TEST_F(GainMapMathTest, P3YuvToRgb) {
+ Color rgb_black = p3YuvToRgb(YuvBlack());
+ EXPECT_RGB_NEAR(rgb_black, RgbBlack());
+
+ Color rgb_white = p3YuvToRgb(YuvWhite());
+ EXPECT_RGB_NEAR(rgb_white, RgbWhite());
+
+ Color rgb_r = p3YuvToRgb(P3YuvRed());
+ EXPECT_RGB_NEAR(rgb_r, RgbRed());
+
+ Color rgb_g = p3YuvToRgb(P3YuvGreen());
+ EXPECT_RGB_NEAR(rgb_g, RgbGreen());
+
+ Color rgb_b = p3YuvToRgb(P3YuvBlue());
+ EXPECT_RGB_NEAR(rgb_b, RgbBlue());
+}
+
+TEST_F(GainMapMathTest, P3RgbToYuv) {
+ Color yuv_black = p3RgbToYuv(RgbBlack());
+ EXPECT_YUV_NEAR(yuv_black, YuvBlack());
+
+ Color yuv_white = p3RgbToYuv(RgbWhite());
+ EXPECT_YUV_NEAR(yuv_white, YuvWhite());
+
+ Color yuv_r = p3RgbToYuv(RgbRed());
+ EXPECT_YUV_NEAR(yuv_r, P3YuvRed());
+
+ Color yuv_g = p3RgbToYuv(RgbGreen());
+ EXPECT_YUV_NEAR(yuv_g, P3YuvGreen());
+
+ Color yuv_b = p3RgbToYuv(RgbBlue());
+ EXPECT_YUV_NEAR(yuv_b, P3YuvBlue());
+}
+
+TEST_F(GainMapMathTest, P3RgbYuvRoundtrip) {
+ Color rgb_black = p3YuvToRgb(p3RgbToYuv(RgbBlack()));
+ EXPECT_RGB_NEAR(rgb_black, RgbBlack());
+
+ Color rgb_white = p3YuvToRgb(p3RgbToYuv(RgbWhite()));
+ EXPECT_RGB_NEAR(rgb_white, RgbWhite());
+
+ Color rgb_r = p3YuvToRgb(p3RgbToYuv(RgbRed()));
+ EXPECT_RGB_NEAR(rgb_r, RgbRed());
+
+ Color rgb_g = p3YuvToRgb(p3RgbToYuv(RgbGreen()));
+ EXPECT_RGB_NEAR(rgb_g, RgbGreen());
+
+ Color rgb_b = p3YuvToRgb(p3RgbToYuv(RgbBlue()));
+ EXPECT_RGB_NEAR(rgb_b, RgbBlue());
+}
TEST_F(GainMapMathTest, Bt2100Luminance) {
EXPECT_FLOAT_EQ(bt2100Luminance(RgbBlack()), 0.0f);
EXPECT_FLOAT_EQ(bt2100Luminance(RgbWhite()), 1.0f);
@@ -461,6 +523,163 @@
EXPECT_RGB_NEAR(rgb_b, RgbBlue());
}
+TEST_F(GainMapMathTest, Bt709ToBt601YuvConversion) {
+ Color yuv_black = srgbRgbToYuv(RgbBlack());
+ EXPECT_YUV_NEAR(yuv709To601(yuv_black), YuvBlack());
+
+ Color yuv_white = srgbRgbToYuv(RgbWhite());
+ EXPECT_YUV_NEAR(yuv709To601(yuv_white), YuvWhite());
+
+ Color yuv_r = srgbRgbToYuv(RgbRed());
+ EXPECT_YUV_NEAR(yuv709To601(yuv_r), P3YuvRed());
+
+ Color yuv_g = srgbRgbToYuv(RgbGreen());
+ EXPECT_YUV_NEAR(yuv709To601(yuv_g), P3YuvGreen());
+
+ Color yuv_b = srgbRgbToYuv(RgbBlue());
+ EXPECT_YUV_NEAR(yuv709To601(yuv_b), P3YuvBlue());
+}
+
+TEST_F(GainMapMathTest, Bt709ToBt2100YuvConversion) {
+ Color yuv_black = srgbRgbToYuv(RgbBlack());
+ EXPECT_YUV_NEAR(yuv709To2100(yuv_black), YuvBlack());
+
+ Color yuv_white = srgbRgbToYuv(RgbWhite());
+ EXPECT_YUV_NEAR(yuv709To2100(yuv_white), YuvWhite());
+
+ Color yuv_r = srgbRgbToYuv(RgbRed());
+ EXPECT_YUV_NEAR(yuv709To2100(yuv_r), Bt2100YuvRed());
+
+ Color yuv_g = srgbRgbToYuv(RgbGreen());
+ EXPECT_YUV_NEAR(yuv709To2100(yuv_g), Bt2100YuvGreen());
+
+ Color yuv_b = srgbRgbToYuv(RgbBlue());
+ EXPECT_YUV_NEAR(yuv709To2100(yuv_b), Bt2100YuvBlue());
+}
+
+TEST_F(GainMapMathTest, Bt601ToBt709YuvConversion) {
+ Color yuv_black = p3RgbToYuv(RgbBlack());
+ EXPECT_YUV_NEAR(yuv601To709(yuv_black), YuvBlack());
+
+ Color yuv_white = p3RgbToYuv(RgbWhite());
+ EXPECT_YUV_NEAR(yuv601To709(yuv_white), YuvWhite());
+
+ Color yuv_r = p3RgbToYuv(RgbRed());
+ EXPECT_YUV_NEAR(yuv601To709(yuv_r), SrgbYuvRed());
+
+ Color yuv_g = p3RgbToYuv(RgbGreen());
+ EXPECT_YUV_NEAR(yuv601To709(yuv_g), SrgbYuvGreen());
+
+ Color yuv_b = p3RgbToYuv(RgbBlue());
+ EXPECT_YUV_NEAR(yuv601To709(yuv_b), SrgbYuvBlue());
+}
+
+TEST_F(GainMapMathTest, Bt601ToBt2100YuvConversion) {
+ Color yuv_black = p3RgbToYuv(RgbBlack());
+ EXPECT_YUV_NEAR(yuv601To2100(yuv_black), YuvBlack());
+
+ Color yuv_white = p3RgbToYuv(RgbWhite());
+ EXPECT_YUV_NEAR(yuv601To2100(yuv_white), YuvWhite());
+
+ Color yuv_r = p3RgbToYuv(RgbRed());
+ EXPECT_YUV_NEAR(yuv601To2100(yuv_r), Bt2100YuvRed());
+
+ Color yuv_g = p3RgbToYuv(RgbGreen());
+ EXPECT_YUV_NEAR(yuv601To2100(yuv_g), Bt2100YuvGreen());
+
+ Color yuv_b = p3RgbToYuv(RgbBlue());
+ EXPECT_YUV_NEAR(yuv601To2100(yuv_b), Bt2100YuvBlue());
+}
+
+TEST_F(GainMapMathTest, Bt2100ToBt709YuvConversion) {
+ Color yuv_black = bt2100RgbToYuv(RgbBlack());
+ EXPECT_YUV_NEAR(yuv2100To709(yuv_black), YuvBlack());
+
+ Color yuv_white = bt2100RgbToYuv(RgbWhite());
+ EXPECT_YUV_NEAR(yuv2100To709(yuv_white), YuvWhite());
+
+ Color yuv_r = bt2100RgbToYuv(RgbRed());
+ EXPECT_YUV_NEAR(yuv2100To709(yuv_r), SrgbYuvRed());
+
+ Color yuv_g = bt2100RgbToYuv(RgbGreen());
+ EXPECT_YUV_NEAR(yuv2100To709(yuv_g), SrgbYuvGreen());
+
+ Color yuv_b = bt2100RgbToYuv(RgbBlue());
+ EXPECT_YUV_NEAR(yuv2100To709(yuv_b), SrgbYuvBlue());
+}
+
+TEST_F(GainMapMathTest, Bt2100ToBt601YuvConversion) {
+ Color yuv_black = bt2100RgbToYuv(RgbBlack());
+ EXPECT_YUV_NEAR(yuv2100To601(yuv_black), YuvBlack());
+
+ Color yuv_white = bt2100RgbToYuv(RgbWhite());
+ EXPECT_YUV_NEAR(yuv2100To601(yuv_white), YuvWhite());
+
+ Color yuv_r = bt2100RgbToYuv(RgbRed());
+ EXPECT_YUV_NEAR(yuv2100To601(yuv_r), P3YuvRed());
+
+ Color yuv_g = bt2100RgbToYuv(RgbGreen());
+ EXPECT_YUV_NEAR(yuv2100To601(yuv_g), P3YuvGreen());
+
+ Color yuv_b = bt2100RgbToYuv(RgbBlue());
+ EXPECT_YUV_NEAR(yuv2100To601(yuv_b), P3YuvBlue());
+}
+
+TEST_F(GainMapMathTest, TransformYuv420) {
+ ColorTransformFn transforms[] = { yuv709To601, yuv709To2100, yuv601To709, yuv601To2100,
+ yuv2100To709, yuv2100To601 };
+ for (const ColorTransformFn& transform : transforms) {
+ jpegr_uncompressed_struct input = Yuv420Image();
+
+ size_t out_buf_size = input.width * input.height * 3 / 2;
+ std::unique_ptr<uint8_t[]> out_buf = std::make_unique<uint8_t[]>(out_buf_size);
+ memcpy(out_buf.get(), input.data, out_buf_size);
+ jpegr_uncompressed_struct output = Yuv420Image();
+ output.data = out_buf.get();
+
+ transformYuv420(&output, 1, 1, transform);
+
+ for (size_t y = 0; y < 4; ++y) {
+ for (size_t x = 0; x < 4; ++x) {
+ // Skip the last chroma sample, which we modified above
+ if (x >= 2 && y >= 2) {
+ continue;
+ }
+
+ // All other pixels should remain unchanged
+ EXPECT_YUV_EQ(getYuv420Pixel(&input, x, y), getYuv420Pixel(&output, x, y));
+ }
+ }
+
+ // modified pixels should be updated as intended by the transformYuv420 algorithm
+ Color in1 = getYuv420Pixel(&input, 2, 2);
+ Color in2 = getYuv420Pixel(&input, 3, 2);
+ Color in3 = getYuv420Pixel(&input, 2, 3);
+ Color in4 = getYuv420Pixel(&input, 3, 3);
+ Color out1 = getYuv420Pixel(&output, 2, 2);
+ Color out2 = getYuv420Pixel(&output, 3, 2);
+ Color out3 = getYuv420Pixel(&output, 2, 3);
+ Color out4 = getYuv420Pixel(&output, 3, 3);
+
+ EXPECT_NEAR(transform(in1).y, out1.y, YuvConversionEpsilon());
+ EXPECT_NEAR(transform(in2).y, out2.y, YuvConversionEpsilon());
+ EXPECT_NEAR(transform(in3).y, out3.y, YuvConversionEpsilon());
+ EXPECT_NEAR(transform(in4).y, out4.y, YuvConversionEpsilon());
+
+ Color expect_uv = (transform(in1) + transform(in2) + transform(in3) + transform(in4)) / 4.0f;
+
+ EXPECT_NEAR(expect_uv.u, out1.u, YuvConversionEpsilon());
+ EXPECT_NEAR(expect_uv.u, out2.u, YuvConversionEpsilon());
+ EXPECT_NEAR(expect_uv.u, out3.u, YuvConversionEpsilon());
+ EXPECT_NEAR(expect_uv.u, out4.u, YuvConversionEpsilon());
+
+ EXPECT_NEAR(expect_uv.v, out1.v, YuvConversionEpsilon());
+ EXPECT_NEAR(expect_uv.v, out2.v, YuvConversionEpsilon());
+ EXPECT_NEAR(expect_uv.v, out3.v, YuvConversionEpsilon());
+ EXPECT_NEAR(expect_uv.v, out4.v, YuvConversionEpsilon());
+ }
+}
+
TEST_F(GainMapMathTest, HlgOetf) {
EXPECT_FLOAT_EQ(hlgOetf(0.0f), 0.0f);
EXPECT_NEAR(hlgOetf(0.04167f), 0.35357f, ComparisonEpsilon());
@@ -693,7 +912,7 @@
TEST_F(GainMapMathTest, EncodeGain) {
ultrahdr_metadata_struct metadata = { .maxContentBoost = 4.0f,
- .minContentBoost = 1.0f / 4.0f };
+ .minContentBoost = 1.0f / 4.0f };
EXPECT_EQ(encodeGain(0.0f, 0.0f, &metadata), 127);
EXPECT_EQ(encodeGain(0.0f, 1.0f, &metadata), 127);
@@ -751,7 +970,7 @@
TEST_F(GainMapMathTest, ApplyGain) {
ultrahdr_metadata_struct metadata = { .maxContentBoost = 4.0f,
- .minContentBoost = 1.0f / 4.0f };
+ .minContentBoost = 1.0f / 4.0f };
float displayBoost = metadata.maxContentBoost;
EXPECT_RGB_NEAR(applyGain(RgbBlack(), 0.0f, &metadata), RgbBlack());