Display P3 encoding update

Author: awxkee

app/src/main/java/com/radzivon/bartoshyk/avif/MainActivity.kt

@@ -93,7 +93,7 @@ class MainActivity : AppCompatActivity() {
         // HDR EXAMPLES - https://us.zonerama.com/williamskeaguidingphotography/Photo/1000120226/1004888131
         lifecycleScope.launch(Dispatchers.IO) {
             val coder = HeifCoder()
-            val buffer = assets.open("pexels_house_wall_p3.jpg").source().buffer().readByteArray()
+            val buffer = assets.open("screenshot_test.png").source().buffer().readByteArray()
             val bitmap = BitmapFactory.decodeByteArray(buffer, 0, buffer.size)
             val encoded = coder.encodeAvif(bitmap, quality = 99, preciseMode = PreciseMode.LOSSLESS)
             val decoded = coder.decode(encoded)

avif-coder/src/main/cpp/JniEncoder.cpp

@@ -192,10 +192,8 @@ jbyteArray encodeBitmap(JNIEnv *env, jobject thiz,
   int bitDepth = 8;
   if (info.format == ANDROID_BITMAP_FORMAT_RGB_565) {
     bitDepth = 8;
-  } else if ((info.format == ANDROID_BITMAP_FORMAT_RGBA_F16 &&
-      heifCompressionFormat == heif_compression_AV1) ||
-      (info.format == ANDROID_BITMAP_FORMAT_RGBA_1010102 &&
-          heifCompressionFormat == heif_compression_AV1)) {
+  } else if ((info.format == ANDROID_BITMAP_FORMAT_RGBA_F16 && heifCompressionFormat == heif_compression_AV1) ||
+      (info.format == ANDROID_BITMAP_FORMAT_RGBA_1010102 && heifCompressionFormat == heif_compression_AV1)) {
     bitDepth = 10;
   }
 

avif-coder/src/main/cpp/colorspace/DataSpaceToNCLX.hpp

@@ -83,8 +83,8 @@ bool colorProfileFromDataSpace(uint8_t *data,
     profile->full_range_flag = true;
     isResolved = true;
   } else if (dataSpace == ADataSpace::ADATASPACE_DISPLAY_P3) {
-    profile->transfer_characteristics = heif_transfer_characteristic_ITU_R_BT_709_5;
-    profile->matrix_coefficients = heif_matrix_coefficients_ITU_R_BT_2020_2_non_constant_luminance;
+    profile->transfer_characteristics = heif_transfer_characteristic_IEC_61966_2_1;
+    profile->matrix_coefficients = heif_matrix_coefficients_ITU_R_BT_601_6;
     profile->color_primaries = heif_color_primaries_SMPTE_EG_432_1;
     profile->full_range_flag = true;
     isResolved = true;

avif-coder/src/main/cpp/colorspace/eotf-inl.h

@@ -172,13 +172,33 @@ HWY_FAST_MATH_INLINE V SRGBEotf(D d, V v) {
   return result;
 }
 
+HWY_FAST_MATH_INLINE float TransferFunction(float v,
+                                            const float c0,
+                                            const float c1,
+                                            const float c2,
+                                            const float c3,
+                                            const float cutoff,
+                                            const float gamma,
+                                            const float c4,
+                                            const float c5) {
+  if (v < 0) {
+    return 0.f;
+  } else if (v >= cutoff) {
+    return c0 * std::powf(c1 * v + c2, gamma) + c3;
+  } else if (v < 1) {
+    return c4 * v + c5;
+  } else {
+    return 1.f;
+  }
+}
+
 HWY_FAST_MATH_INLINE float SRGBOetf(const float linear) {
   if (linear < 0.0f) {
     return 0.0f;
   } else if (linear < 0.0030412825601275209f) {
     return linear * 12.92f;
   } else if (linear < 1.0f) {
-    return 1.0550107189475866f * powf(linear, 1.0f / 2.4f) - 0.0550107189475866f;
+    return 1.0550107189475866f * std::powf(linear, 1.0f / 2.4f) - 0.0550107189475866f;
   } else {
     return 1.0f;
   }

avif-coder/src/main/cpp/hwy/ops/generic_ops-inl.h

@@ -2599,38 +2599,14 @@ HWY_API VFromD<DN> ReorderDemote2To(DN dn, V a, V b) {
 
 template<class D, HWY_IF_F32_D(D)>
 HWY_API VFromD<D> PromoteTo(D df, Vec<Rebind<uint16_t, D>> v) {
-    const RebindToUnsigned<decltype(df)> du32;
-
-    // Floats have 23 bits of mantissa.
-    // We want least significant 8 bits to be shifted to [ 0 .. 255 ], therefore need to add 2^23
-    // See this page for details: https://www.h-schmidt.net/FloatConverter/IEEE754.html
-    // If you want output floats in [ 0 .. 255.0 / 256.0 ] interval, change into 2^15 = 0x47000000
-    constexpr uint32_t offsetValue = 0x4b000000;
-    // Check disassembly & verify your compiler has moved this initialization outside the loop
-    const auto offsetInt = Set(du32, offsetValue);
-    // Bitwise is probably slightly faster than addition, delivers same results for our input
-    auto u32 = PromoteTo(du32, v);
-    u32 = Or(u32, offsetInt);
-    // The only FP operation required is subtraction, hopefully faster than UCVTF
-    return Sub(BitCast(df, u32), BitCast(df, offsetInt));
+  const RebindToUnsigned<decltype(df)> du32;
+  return ConvertTo(df, PromoteTo(du32, v));
 }
 
 template<class D, HWY_IF_F32_D(D)>
 HWY_API VFromD<D> PromoteTo(D df, Vec<Rebind<uint8_t, D>> v) {
-    const RebindToUnsigned<decltype(df)> du32;
-
-    // Floats have 23 bits of mantissa.
-    // We want least significant 8 bits to be shifted to [ 0 .. 255 ], therefore need to add 2^23
-    // See this page for details: https://www.h-schmidt.net/FloatConverter/IEEE754.html
-    // If you want output floats in [ 0 .. 255.0 / 256.0 ] interval, change into 2^15 = 0x47000000
-    constexpr uint32_t offsetValue = 0x4b000000;
-    // Check disassembly & verify your compiler has moved this initialization outside the loop
-    const auto offsetInt = Set(du32, offsetValue);
-    // Bitwise is probably slightly faster than addition, delivers same results for our input
-    auto u32 = PromoteTo(du32, v);
-    u32 = Or(u32, offsetInt);
-    // The only FP operation required is subtraction, hopefully faster than UCVTF
-    return Sub(BitCast(df, u32), BitCast(df, offsetInt));
+  const RebindToUnsigned<decltype(df)> du32;
+  return ConvertTo(df, PromoteTo(du32, v));
 }
 
 template<class D, HWY_IF_U8_D(D)>

build.gradle

@@ -1,7 +1,7 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 plugins {
     id 'com.android.application' version '8.2.0' apply false
-    id 'com.android.library' version '8.3.0' apply false
+    id 'com.android.library' version '8.3.1' apply false
     id 'org.jetbrains.kotlin.android' version '1.7.20' apply false
     id 'com.google.devtools.ksp' version '1.8.10-1.0.9' apply false
 }

gradle/wrapper/gradle-wrapper.properties

@@ -25,7 +25,7 @@
 
 #Wed Dec 28 11:02:12 ICT 2022
 distributionBase=GRADLE_USER_HOME
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.4-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.6-bin.zip
 distributionPath=wrapper/dists
 zipStorePath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME