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HDR: Apply OETF in HDR external sampler GLSL shader.

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This should fix how color matrix transforms look when applied on HDR colors

PiperOrigin-RevId: 491323228
This commit is contained in:
huangdarwin 2022-11-28 14:07:59 +00:00 committed by Rohit Singh
parent c9b9054c0b
commit 49c87f3b77
3 changed files with 92 additions and 26 deletions
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19
libraries/effect/src/main/assets/shaders/fragment_shader_oetf_es3.glsl
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@ -14,12 +14,13 @@
// limitations under the License.
// ES 3 fragment shader that:
// 1. samples optical linear BT.2020 RGB from a (non-external) texture with
// uTexSampler, and applies a 4x4 RGB color matrix to change the pixel
// colors,
// 2. applies the HLG or PQ OETF to yield electrical (HLG or PQ) BT.2020 RGB,
// and
// 3. copies this converted texture color to the current output.
// 1. Samples optical linear BT.2020 RGB from a (non-external) texture with
// uTexSampler.
// 2. Applies a 4x4 RGB color matrix to change the pixel colors.
// 3. Applies the HLG or PQ OETF to yield electrical (HLG or PQ) BT.2020 RGB,
// based on uOetfColorTransfer.
// 4. Copies this converted texture color to the current output.
// The output will be red if an error has occurred.
precision mediump float;
uniform sampler2D uTexSampler;
@ -75,8 +76,8 @@ highp vec3 pqOetf(highp vec3 linearColor) {
}
// Applies the appropriate OETF to convert linear optical signals to nonlinear
// electrical signals. Input and output are both normalzied to [0, 1].
highp vec3 getElectricalColor(highp vec3 linearColor) {
// electrical signals. Input and output are both normalized to [0, 1].
highp vec3 applyOetf(highp vec3 linearColor) {
// LINT.IfChange(color_transfer)
const int COLOR_TRANSFER_ST2084 = 6;
const int COLOR_TRANSFER_HLG = 7;
@ -94,5 +95,5 @@ void main() {
vec4 inputColor = texture(uTexSampler, vTexSamplingCoord);
// transformedColors is an optical color.
vec4 transformedColors = uRgbMatrix * vec4(inputColor.rgb, 1);
outColor = vec4(getElectricalColor(transformedColors.rgb), inputColor.a);
outColor = vec4(applyOetf(transformedColors.rgb), inputColor.a);
}

88
libraries/effect/src/main/assets/shaders/fragment_shader_transformation_external_yuv_es3.glsl
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@ -20,11 +20,13 @@
// https://www.khronos.org/registry/OpenGL/extensions/EXT/EXT_YUV_target.txt,
// 2. Applies a YUV to RGB conversion using the specified color transform
// uYuvToRgbColorTransform, yielding electrical (HLG or PQ) BT.2020 RGB,
// 3. If uEotfColorTransfer is COLOR_TRANSFER_NO_VALUE, outputs electrical
// (HLG or PQ) BT.2020 RGB. Otherwise, outputs optical linear BT.2020 RGB for
// intermediate shaders by applying the HLG or PQ EOTF.
// 4. Copies this converted texture color to the current output, with alpha = 1,
// while applying a 4x4 RGB color matrix to change the pixel colors.
// 3. Applies an EOTF based on uEotfColorTransfer, yielding optical linear
// BT.2020 RGB.
// 4. Applies a 4x4 RGB color matrix to change the pixel colors.
// 5. If uOetfColorTransfer is COLOR_TRANSFER_LINEAR, outputs linear colors as
// is to intermediate shaders. Otherwise, applies the HLG or PQ OETF, based
// on uOetfColorTransfer, to provide the corresponding output electrical color.
// The output will be red if an error has occurred.
#extension GL_OES_EGL_image_external : require
#extension GL_EXT_YUV_target : require
@ -33,7 +35,12 @@ uniform __samplerExternal2DY2YEXT uTexSampler;
uniform mat3 uYuvToRgbColorTransform;
uniform mat4 uRgbMatrix;
// C.java#ColorTransfer value.
// Only COLOR_TRANSFER_ST2084 and COLOR_TRANSFER_HLG are allowed.
uniform int uEotfColorTransfer;
// C.java#ColorTransfer value.
// Only COLOR_TRANSFER_LINEAR, COLOR_TRANSFER_ST2084, and COLOR_TRANSFER_HLG are
// allowed.
uniform int uOetfColorTransfer;
in vec2 vTexSamplingCoord;
out vec4 outColor;
@ -81,19 +88,74 @@ highp vec3 pqEotf(highp vec3 pqColor) {
// Applies the appropriate EOTF to convert nonlinear electrical values to linear
// optical values. Input and output are both normalized to [0, 1].
highp vec3 getOpticalColor(highp vec3 electricalColor) {
highp vec3 applyEotf(highp vec3 electricalColor) {
// LINT.IfChange(color_transfer)
const int COLOR_TRANSFER_ST2084 = 6;
const int COLOR_TRANSFER_HLG = 7;
const int FORMAT_NO_VALUE = -1;
if (uEotfColorTransfer == COLOR_TRANSFER_ST2084) {
return pqEotf(electricalColor);
} else if (uEotfColorTransfer == COLOR_TRANSFER_HLG) {
return hlgEotf(electricalColor);
} else if (uEotfColorTransfer == FORMAT_NO_VALUE) {
return electricalColor;
} else {
// Output red as an obviously visible error.
return vec3(1.0, 0.0, 0.0);
}
}
// HLG OETF for one channel.
highp float hlgOetfSingleChannel(highp float linearChannel) {
// Specification:
// https://www.khronos.org/registry/DataFormat/specs/1.3/dataformat.1.3.inline.html#TRANSFER_HLG
// Reference implementation:
// https://cs.android.com/android/platform/superproject/+/master:frameworks/native/libs/renderengine/gl/ProgramCache.cpp;l=529-543;drc=de09f10aa504fd8066370591a00c9ff1cafbb7fa
const highp float a = 0.17883277;
const highp float b = 0.28466892;
const highp float c = 0.55991073;
return linearChannel <= 1.0 / 12.0 ? sqrt(3.0 * linearChannel) :
a * log(12.0 * linearChannel - b) + c;
}
// BT.2100 / BT.2020 HLG OETF.
highp vec3 hlgOetf(highp vec3 linearColor) {
return vec3(
hlgOetfSingleChannel(linearColor.r),
hlgOetfSingleChannel(linearColor.g),
hlgOetfSingleChannel(linearColor.b)
);
}
// BT.2100 / BT.2020, PQ / ST2084 OETF.
highp vec3 pqOetf(highp vec3 linearColor) {
// Specification:
// https://registry.khronos.org/DataFormat/specs/1.3/dataformat.1.3.inline.html#TRANSFER_PQ
// Reference implementation:
// https://cs.android.com/android/platform/superproject/+/master:frameworks/native/libs/renderengine/gl/ProgramCache.cpp;l=514-527;drc=de09f10aa504fd8066370591a00c9ff1cafbb7fa
const highp float m1 = (2610.0 / 16384.0);
const highp float m2 = (2523.0 / 4096.0) * 128.0;
const highp float c1 = (3424.0 / 4096.0);
const highp float c2 = (2413.0 / 4096.0) * 32.0;
const highp float c3 = (2392.0 / 4096.0) * 32.0;
highp vec3 temp = pow(linearColor, vec3(m1));
temp = (c1 + c2 * temp) / (1.0 + c3 * temp);
return pow(temp, vec3(m2));
}
// Applies the appropriate OETF to convert linear optical signals to nonlinear
// electrical signals. Input and output are both normalized to [0, 1].
highp vec3 applyOetf(highp vec3 linearColor) {
// LINT.IfChange(color_transfer_oetf)
const int COLOR_TRANSFER_LINEAR = 1;
const int COLOR_TRANSFER_ST2084 = 6;
const int COLOR_TRANSFER_HLG = 7;
if(uOetfColorTransfer == COLOR_TRANSFER_ST2084) {
return pqOetf(linearColor);
} else if(uOetfColorTransfer == COLOR_TRANSFER_HLG) {
return hlgOetf(linearColor);
} else if (uOetfColorTransfer == COLOR_TRANSFER_LINEAR) {
return linearColor;
} else {
// Output red as an obviously visible error.
return vec3(1.0, 0.0, 0.0);
@ -107,7 +169,7 @@ vec3 yuvToRgb(vec3 yuv) {
void main() {
vec3 srcYuv = texture(uTexSampler, vTexSamplingCoord).xyz;
vec3 rgb = yuvToRgb(srcYuv);
outColor = uRgbMatrix * vec4(getOpticalColor(rgb), 1.0);
// TODO(b/241902517): Transform optical to electrical colors.
vec4 opticalColor = vec4(applyEotf(yuvToRgb(srcYuv)), 1.0);
vec4 transformedColors = uRgbMatrix * opticalColor;
outColor = vec4(applyOetf(transformedColors.rgb), 1.0);
}

11
libraries/effect/src/main/java/androidx/media3/effect/MatrixTextureProcessor.java
View File

@ -24,7 +24,6 @@ import android.opengl.Matrix;
import android.util.Pair;
import androidx.media3.common.C;
import androidx.media3.common.ColorInfo;
import androidx.media3.common.Format;
import androidx.media3.common.FrameProcessingException;
import androidx.media3.common.util.GlProgram;
import androidx.media3.common.util.GlUtil;
@ -154,7 +153,6 @@ import java.util.List;
context, VERTEX_SHADER_TRANSFORMATION_PATH, FRAGMENT_SHADER_TRANSFORMATION_PATH);
// No transfer functions needed, because input and output are both optical colors.
// TODO(b/241902517): Add transfer functions since existing color filters may change the colors.
return new MatrixTextureProcessor(
glProgram,
ImmutableList.copyOf(matrixTransformations),
@ -216,6 +214,8 @@ import java.util.List;
checkArgument(
colorTransfer == C.COLOR_TRANSFER_HLG || colorTransfer == C.COLOR_TRANSFER_ST2084);
glProgram.setIntUniform("uEotfColorTransfer", colorTransfer);
// No OETF needed, because the intended output here is optical colors.
glProgram.setIntUniform("uOetfColorTransfer", C.COLOR_TRANSFER_LINEAR);
} else {
glProgram.setIntUniform("uApplyOetf", 0);
}
@ -319,8 +319,11 @@ import java.util.List;
? BT2020_FULL_RANGE_YUV_TO_RGB_COLOR_TRANSFORM_MATRIX
: BT2020_LIMITED_RANGE_YUV_TO_RGB_COLOR_TRANSFORM_MATRIX);
// No transfer functions needed, because the EOTF and OETF cancel out.
glProgram.setIntUniform("uEotfColorTransfer", Format.NO_VALUE);
@C.ColorTransfer int colorTransfer = electricalColorInfo.colorTransfer;
checkArgument(
colorTransfer == C.COLOR_TRANSFER_HLG || colorTransfer == C.COLOR_TRANSFER_ST2084);
glProgram.setIntUniform("uEotfColorTransfer", colorTransfer);
glProgram.setIntUniform("uOetfColorTransfer", colorTransfer);
} else {
glProgram.setIntUniform("uApplyOetf", 1);
}