Allow SurfaceFlinger to treat 170M as sRGB.
Introduce a debug sysprop, defaulted to false, to allow for rewriting
the transfer function to sRGB when set to true.
This is due to several considerations:
1. SurfaceFlinger has not color managed SMPTE 170M properly ever since
color management was introduced in Android O, and was only fixed in
Android 13. This means that some camera -> encoding -> storage ->
playback flows may be incorrectly calibrated on some devices since
SMPTE 170M was reinterpreted as sRGB for a long time.
2. BT. 1886 recommends a reference EOTF of gamma 2.4 with tuneable
parameters to approximate a CRT on a non-CRT display. Because the
framework doesn't support BT. 1886 and it's too late to add support,
casting as sRGB is probably okay for now and matches old behavior.
3. Typical Rec. 709 content is graded assuming a dim surround, but phone
displays are used in a wide range of viewing environments, which
means that viewing Rec. 709 content in a bright environment may
appear to have lower contrast. Decoding as sRGB will push the dark
codes into lower luminance levels, which will improve contrast in
those scenarios. Note that it's better to adjust contrast based on
the ambient viewing environment, but again it's too late for Android
13 to improve the color pipeline in the GPU.
Bug: 229442032
Test: Photos playback after recording a video
Change-Id: I64fc8f2ea77f8e595333de36fb9da2979d8316ca
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/Output.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/Output.h
index 5846e67..db2fd1b 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/Output.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/Output.h
@@ -267,6 +267,9 @@
// Enables predicting composition strategy to run client composition earlier
virtual void setPredictCompositionStrategy(bool) = 0;
+ // Enables overriding the 170M trasnfer function as sRGB
+ virtual void setTreat170mAsSrgb(bool) = 0;
+
protected:
virtual void setDisplayColorProfile(std::unique_ptr<DisplayColorProfile>) = 0;
virtual void setRenderSurface(std::unique_ptr<RenderSurface>) = 0;
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/Output.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/Output.h
index 0feb9f7..31c51e6 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/Output.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/Output.h
@@ -108,6 +108,7 @@
void cacheClientCompositionRequests(uint32_t) override;
bool canPredictCompositionStrategy(const CompositionRefreshArgs&) override;
void setPredictCompositionStrategy(bool) override;
+ void setTreat170mAsSrgb(bool) override;
// Testing
const ReleasedLayers& getReleasedLayersForTest() const;
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/OutputCompositionState.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/OutputCompositionState.h
index 61be983..c65d467 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/OutputCompositionState.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/OutputCompositionState.h
@@ -162,6 +162,8 @@
CompositionStrategyPredictionState strategyPrediction =
CompositionStrategyPredictionState::DISABLED;
+ bool treat170mAsSrgb = false;
+
// Debugging
void dump(std::string& result) const;
};
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/Output.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/Output.h
index fa86076..cb9fbad 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/Output.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/Output.h
@@ -132,6 +132,7 @@
MOCK_METHOD1(cacheClientCompositionRequests, void(uint32_t));
MOCK_METHOD1(canPredictCompositionStrategy, bool(const CompositionRefreshArgs&));
MOCK_METHOD1(setPredictCompositionStrategy, void(bool));
+ MOCK_METHOD1(setTreat170mAsSrgb, void(bool));
};
} // namespace android::compositionengine::mock
diff --git a/services/surfaceflinger/CompositionEngine/src/Output.cpp b/services/surfaceflinger/CompositionEngine/src/Output.cpp
index ec86731..4c30f99 100644
--- a/services/surfaceflinger/CompositionEngine/src/Output.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/Output.cpp
@@ -1488,6 +1488,10 @@
}
}
+void Output::setTreat170mAsSrgb(bool enable) {
+ editState().treat170mAsSrgb = enable;
+}
+
bool Output::canPredictCompositionStrategy(const CompositionRefreshArgs& refreshArgs) {
if (!getState().isEnabled || !mHwComposerAsyncWorker) {
ALOGV("canPredictCompositionStrategy disabled");
diff --git a/services/surfaceflinger/CompositionEngine/src/OutputCompositionState.cpp b/services/surfaceflinger/CompositionEngine/src/OutputCompositionState.cpp
index 3b85e3b..948c0c9 100644
--- a/services/surfaceflinger/CompositionEngine/src/OutputCompositionState.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/OutputCompositionState.cpp
@@ -66,6 +66,9 @@
out.append("\n ");
dumpVal(out, "compositionStrategyPredictionState", ftl::enum_string(strategyPrediction));
+ out.append("\n ");
+ dumpVal(out, "treate170mAsSrgb", treat170mAsSrgb);
+
out += '\n';
}
diff --git a/services/surfaceflinger/CompositionEngine/src/OutputLayer.cpp b/services/surfaceflinger/CompositionEngine/src/OutputLayer.cpp
index 3289d55..61c53df 100644
--- a/services/surfaceflinger/CompositionEngine/src/OutputLayer.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/OutputLayer.cpp
@@ -322,6 +322,17 @@
? outputState.targetDataspace
: layerFEState->dataspace;
+ // Override the dataspace transfer from 170M to sRGB if the device configuration requests this.
+ // We do this here instead of in buffer info so that dumpsys can still report layers that are
+ // using the 170M transfer. Also we only do this if the colorspace is not agnostic for the
+ // layer, in case the color profile uses a 170M transfer function.
+ if (outputState.treat170mAsSrgb && !layerFEState->isColorspaceAgnostic &&
+ (state.dataspace & HAL_DATASPACE_TRANSFER_MASK) == HAL_DATASPACE_TRANSFER_SMPTE_170M) {
+ state.dataspace = static_cast<ui::Dataspace>(
+ (state.dataspace & HAL_DATASPACE_STANDARD_MASK) |
+ (state.dataspace & HAL_DATASPACE_RANGE_MASK) | HAL_DATASPACE_TRANSFER_SRGB);
+ }
+
// For hdr content, treat the white point as the display brightness - HDR content should not be
// boosted or dimmed.
// If the layer explicitly requests to disable dimming, then don't dim either.
diff --git a/services/surfaceflinger/CompositionEngine/tests/OutputLayerTest.cpp b/services/surfaceflinger/CompositionEngine/tests/OutputLayerTest.cpp
index ceee48c..ca4f397 100644
--- a/services/surfaceflinger/CompositionEngine/tests/OutputLayerTest.cpp
+++ b/services/surfaceflinger/CompositionEngine/tests/OutputLayerTest.cpp
@@ -657,6 +657,23 @@
EXPECT_EQ(ui::Dataspace::V0_SCRGB, mOutputLayer.getState().dataspace);
}
+TEST_F(OutputLayerUpdateCompositionStateTest, setsOutputLayerColorspaceWith170mReplacement) {
+ mLayerFEState.dataspace = ui::Dataspace::TRANSFER_SMPTE_170M;
+ mOutputState.targetDataspace = ui::Dataspace::V0_SCRGB;
+ mOutputState.treat170mAsSrgb = false;
+ mLayerFEState.isColorspaceAgnostic = false;
+
+ mOutputLayer.updateCompositionState(false, false, ui::Transform::RotationFlags::ROT_0);
+
+ EXPECT_EQ(ui::Dataspace::TRANSFER_SMPTE_170M, mOutputLayer.getState().dataspace);
+
+ // Rewrite SMPTE 170M as sRGB
+ mOutputState.treat170mAsSrgb = true;
+ mOutputLayer.updateCompositionState(false, false, ui::Transform::RotationFlags::ROT_0);
+
+ EXPECT_EQ(ui::Dataspace::TRANSFER_SRGB, mOutputLayer.getState().dataspace);
+}
+
TEST_F(OutputLayerUpdateCompositionStateTest, setsWhitePointNitsAndDimmingRatioCorrectly) {
mOutputState.sdrWhitePointNits = 200.f;
mOutputState.displayBrightnessNits = 800.f;
diff --git a/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp b/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp
index 42c8b37..3a3c91e 100644
--- a/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp
+++ b/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp
@@ -248,6 +248,20 @@
}
/*
+ * Output::setTreat170mAsSrgb()
+ */
+
+TEST_F(OutputTest, setTreat170mAsSrgb) {
+ EXPECT_FALSE(mOutput->getState().treat170mAsSrgb);
+
+ mOutput->setTreat170mAsSrgb(true);
+ EXPECT_TRUE(mOutput->getState().treat170mAsSrgb);
+
+ mOutput->setTreat170mAsSrgb(false);
+ EXPECT_FALSE(mOutput->getState().treat170mAsSrgb);
+}
+
+/*
* Output::setLayerCachingEnabled()
*/
diff --git a/services/surfaceflinger/DisplayDevice.cpp b/services/surfaceflinger/DisplayDevice.cpp
index 52529d6..a915b61 100644
--- a/services/surfaceflinger/DisplayDevice.cpp
+++ b/services/surfaceflinger/DisplayDevice.cpp
@@ -89,6 +89,7 @@
}
mCompositionDisplay->setPredictCompositionStrategy(mFlinger->mPredictCompositionStrategy);
+ mCompositionDisplay->setTreat170mAsSrgb(mFlinger->mTreat170mAsSrgb);
mCompositionDisplay->createDisplayColorProfile(
compositionengine::DisplayColorProfileCreationArgsBuilder()
.setHasWideColorGamut(args.hasWideColorGamut)
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index 3a92ca4..e1eec8b 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -47,6 +47,7 @@
#include <stdint.h>
#include <stdlib.h>
#include <sys/types.h>
+#include <system/graphics-base-v1.0.h>
#include <ui/DataspaceUtils.h>
#include <ui/DebugUtils.h>
#include <ui/GraphicBuffer.h>
@@ -600,6 +601,18 @@
layerSettings.alpha = alpha;
layerSettings.sourceDataspace = getDataSpace();
+ // Override the dataspace transfer from 170M to sRGB if the device configuration requests this.
+ // We do this here instead of in buffer info so that dumpsys can still report layers that are
+ // using the 170M transfer.
+ if (mFlinger->mTreat170mAsSrgb &&
+ (layerSettings.sourceDataspace & HAL_DATASPACE_TRANSFER_MASK) ==
+ HAL_DATASPACE_TRANSFER_SMPTE_170M) {
+ layerSettings.sourceDataspace = static_cast<ui::Dataspace>(
+ (layerSettings.sourceDataspace & HAL_DATASPACE_STANDARD_MASK) |
+ (layerSettings.sourceDataspace & HAL_DATASPACE_RANGE_MASK) |
+ HAL_DATASPACE_TRANSFER_SRGB);
+ }
+
layerSettings.whitePointNits = targetSettings.whitePointNits;
switch (targetSettings.blurSetting) {
case LayerFE::ClientCompositionTargetSettings::BlurSetting::Enabled:
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index d39176b..65c1c97 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -419,6 +419,9 @@
property_get("debug.sf.predict_hwc_composition_strategy", value, "1");
mPredictCompositionStrategy = atoi(value);
+ property_get("debug.sf.treat_170m_as_sRGB", value, "0");
+ mTreat170mAsSrgb = atoi(value);
+
// We should be reading 'persist.sys.sf.color_saturation' here
// but since /data may be encrypted, we need to wait until after vold
// comes online to attempt to read the property. The property is
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 74e0407..c70e174 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -349,6 +349,12 @@
// run parallel to the hwc validateDisplay call and re-run if the predition is incorrect.
bool mPredictCompositionStrategy = false;
+ // If true, then any layer with a SMPTE 170M transfer function is decoded using the sRGB
+ // transfer instead. This is mainly to preserve legacy behavior, where implementations treated
+ // SMPTE 170M as sRGB prior to color management being implemented, and now implementations rely
+ // on this behavior to increase contrast for some media sources.
+ bool mTreat170mAsSrgb = false;
+
protected:
// We're reference counted, never destroy SurfaceFlinger directly
virtual ~SurfaceFlinger();