Clean YCgCo-R a bit. (#2418)
diff --git a/src/reformat.c b/src/reformat.c
index d59435d..3a34d5f 100644
--- a/src/reformat.c
+++ b/src/reformat.c
@@ -361,7 +361,7 @@
yuvBlock[bI][bJ].v = 0.5f * (rgbPixel[0] - rgbPixel[2]);
#if defined(AVIF_ENABLE_EXPERIMENTAL_YCGCO_R)
} else if (state.yuv.mode == AVIF_REFORMAT_MODE_YCGCO_RE || state.yuv.mode == AVIF_REFORMAT_MODE_YCGCO_RO) {
- // Formulas from JVET-U0093.
+ // Formulas 58,59,60,61 from https://www.itu.int/rec/T-REC-H.273-202407-P
const int R = (int)avifRoundf(AVIF_CLAMP(rgbPixel[0] * rgbMaxChannelF, 0.0f, rgbMaxChannelF));
const int G = (int)avifRoundf(AVIF_CLAMP(rgbPixel[1] * rgbMaxChannelF, 0.0f, rgbMaxChannelF));
const int B = (int)avifRoundf(AVIF_CLAMP(rgbPixel[2] * rgbMaxChannelF, 0.0f, rgbMaxChannelF));
@@ -771,6 +771,7 @@
R = t + Cr;
#if defined(AVIF_ENABLE_EXPERIMENTAL_YCGCO_R)
} else if (state->yuv.mode == AVIF_REFORMAT_MODE_YCGCO_RE || state->yuv.mode == AVIF_REFORMAT_MODE_YCGCO_RO) {
+ // YCgCoRe/YCgCoRo: Formulas 62,63,64,65 from https://www.itu.int/rec/T-REC-H.273-202407-P
const int YY = unormY;
const int Cg = (int)avifRoundf(Cb * yuvMaxChannel);
const int Co = (int)avifRoundf(Cr * yuvMaxChannel);
diff --git a/tests/gtest/avifrgbtoyuvtest.cc b/tests/gtest/avifrgbtoyuvtest.cc
index d03e5ef..5db8e90 100644
--- a/tests/gtest/avifrgbtoyuvtest.cc
+++ b/tests/gtest/avifrgbtoyuvtest.cc
@@ -358,26 +358,45 @@
for (avifRange yuv_range : {AVIF_RANGE_LIMITED, AVIF_RANGE_FULL}) {
for (decltype(AVIF_MATRIX_COEFFICIENTS_IDENTITY) matrix_coefficients :
{
- AVIF_MATRIX_COEFFICIENTS_BT709,
- AVIF_MATRIX_COEFFICIENTS_UNSPECIFIED,
- AVIF_MATRIX_COEFFICIENTS_FCC,
- AVIF_MATRIX_COEFFICIENTS_BT470BG,
- AVIF_MATRIX_COEFFICIENTS_BT601,
- AVIF_MATRIX_COEFFICIENTS_SMPTE240,
- AVIF_MATRIX_COEFFICIENTS_YCGCO,
- AVIF_MATRIX_COEFFICIENTS_BT2020_NCL,
- AVIF_MATRIX_COEFFICIENTS_CHROMA_DERIVED_NCL
- // These are unsupported. See avifPrepareReformatState().
- // AVIF_MATRIX_COEFFICIENTS_BT2020_CL
- // AVIF_MATRIX_COEFFICIENTS_SMPTE2085
- // AVIF_MATRIX_COEFFICIENTS_CHROMA_DERIVED_CL
- // AVIF_MATRIX_COEFFICIENTS_ICTCP
+ AVIF_MATRIX_COEFFICIENTS_BT709,
+ AVIF_MATRIX_COEFFICIENTS_UNSPECIFIED,
+ AVIF_MATRIX_COEFFICIENTS_FCC,
+ AVIF_MATRIX_COEFFICIENTS_BT470BG,
+ AVIF_MATRIX_COEFFICIENTS_BT601,
+ AVIF_MATRIX_COEFFICIENTS_SMPTE240,
+ AVIF_MATRIX_COEFFICIENTS_YCGCO,
+ AVIF_MATRIX_COEFFICIENTS_BT2020_NCL,
+ AVIF_MATRIX_COEFFICIENTS_CHROMA_DERIVED_NCL,
+#if defined(AVIF_ENABLE_EXPERIMENTAL_YCGCO_R)
+ AVIF_MATRIX_COEFFICIENTS_YCGCO_RE,
+ AVIF_MATRIX_COEFFICIENTS_YCGCO_RO,
+#endif
+ // These are unsupported. See avifPrepareReformatState().
+ // AVIF_MATRIX_COEFFICIENTS_BT2020_CL
+ // AVIF_MATRIX_COEFFICIENTS_SMPTE2085
+ // AVIF_MATRIX_COEFFICIENTS_CHROMA_DERIVED_CL
+ // AVIF_MATRIX_COEFFICIENTS_ICTCP
}) {
if (matrix_coefficients == AVIF_MATRIX_COEFFICIENTS_YCGCO &&
yuv_range == AVIF_RANGE_LIMITED) {
// See avifPrepareReformatState().
continue;
}
+#if defined(AVIF_ENABLE_EXPERIMENTAL_YCGCO_R)
+ if ((matrix_coefficients == AVIF_MATRIX_COEFFICIENTS_YCGCO_RE &&
+ yuv_depth - 2 != rgb_depth) ||
+ (matrix_coefficients == AVIF_MATRIX_COEFFICIENTS_YCGCO_RO &&
+ yuv_depth - 1 != rgb_depth)) {
+ // See avifPrepareReformatState().
+ continue;
+ }
+ if ((matrix_coefficients == AVIF_MATRIX_COEFFICIENTS_YCGCO_RE ||
+ matrix_coefficients == AVIF_MATRIX_COEFFICIENTS_YCGCO_RO) &&
+ yuv_range != AVIF_RANGE_FULL) {
+ // YCgCo-R is for lossless.
+ continue;
+ }
+#endif
for (avifChromaDownsampling chroma_downsampling :
{AVIF_CHROMA_DOWNSAMPLING_FASTEST,
AVIF_CHROMA_DOWNSAMPLING_BEST_QUALITY}) {
@@ -458,6 +477,10 @@
AVIF_MATRIX_COEFFICIENTS_BT709;
constexpr avifMatrixCoefficients kMatrixCoefficientsIdentity =
AVIF_MATRIX_COEFFICIENTS_IDENTITY;
+#if defined(AVIF_ENABLE_EXPERIMENTAL_YCGCO_R)
+constexpr avifMatrixCoefficients kMatrixCoefficientsYCgCoRe =
+ AVIF_MATRIX_COEFFICIENTS_YCGCO_RE;
+#endif
// This is the default avifenc setup when encoding from 8b PNG files to AVIF.
INSTANTIATE_TEST_SUITE_P(
@@ -592,6 +615,22 @@
/*max_abs_average_diff=*/Values(0.),
/*min_psnr=*/Values(99.)));
+#if defined(AVIF_ENABLE_EXPERIMENTAL_YCGCO_R)
+// Tests YCGCO_RE is lossless.
+INSTANTIATE_TEST_SUITE_P(YCgCo_Re8b, RGBToYUVTest,
+ Combine(/*rgb_depth=*/Values(8),
+ /*yuv_depth=*/Values(10),
+ Values(AVIF_RGB_FORMAT_RGBA),
+ Values(AVIF_PIXEL_FORMAT_YUV444),
+ Values(AVIF_RANGE_FULL),
+ Values(kMatrixCoefficientsYCgCoRe),
+ Values(AVIF_CHROMA_DOWNSAMPLING_AUTOMATIC),
+ /*add_noise=*/Values(true),
+ /*rgb_step=*/Values(101),
+ /*max_abs_average_diff=*/Values(0.),
+ /*min_psnr=*/Values(99.)));
+#endif
+
// Coverage for reformat_libsharpyuv.c.
INSTANTIATE_TEST_SUITE_P(
SharpYuv8Bit, RGBToYUVTest,
