Effect: Create GlEffect.isNoOp to simplify Transformer.

This will also allow us to skip transcodes in the future for other effects, like
cropping, color effects, etc.

PiperOrigin-RevId: 507765618

library/effect/src/main/java/com/google/android/exoplayer2/effect/Crop.java

@@ -91,4 +91,12 @@ public final class Crop implements MatrixTransformation {
   public Matrix getMatrix(long presentationTimeUs) {
     return checkStateNotNull(transformationMatrix, "configure must be called first");
   }
+
+  @Override
+  public boolean isNoOp(int inputWidth, int inputHeight) {
+    Size outputSize = configure(inputWidth, inputHeight);
+    return checkStateNotNull(transformationMatrix).isIdentity()
+        && inputWidth == outputSize.getWidth()
+        && inputHeight == outputSize.getHeight();
+  }
 }

library/effect/src/main/java/com/google/android/exoplayer2/effect/GlEffect.java

@@ -38,4 +38,19 @@ public interface GlEffect extends Effect {
    */
   GlShaderProgram toGlShaderProgram(Context context, boolean useHdr)
       throws FrameProcessingException;
+
+  /**
+   * Returns whether a {@link GlEffect} applies no change at every timestamp.
+   *
+   * <p>This can be used as a hint to skip this instance.
+   *
+   * @param inputWidth The input frame width, in pixels.
+   * @param inputHeight The input frame height, in pixels.
+   */
+  default boolean isNoOp(int inputWidth, int inputHeight) {
+    // TODO(b/265927935): Generalize this logic by implementing this method on all
+    //  subclasses, and deleting the default implementation here. Otherwise, some no-op effects may
+    //  not be properly detected or handled.
+    return false;
+  }
 }

library/effect/src/main/java/com/google/android/exoplayer2/effect/Presentation.java

@@ -212,6 +212,14 @@ public final class Presentation implements MatrixTransformation {
     return checkStateNotNull(transformationMatrix, "configure must be called first");
   }
 
+  @Override
+  public boolean isNoOp(int inputWidth, int inputHeight) {
+    configure(inputWidth, inputHeight);
+    return checkStateNotNull(transformationMatrix).isIdentity()
+        && inputWidth == Math.round(outputWidth)
+        && inputHeight == Math.round(outputHeight);
+  }
+
   @RequiresNonNull("transformationMatrix")
   private void applyAspectRatio() {
     float inputAspectRatio = outputWidth / outputHeight;

library/effect/src/main/java/com/google/android/exoplayer2/effect/ScaleToFitTransformation.java

@@ -90,13 +90,6 @@ public final class ScaleToFitTransformation implements MatrixTransformation {
     }
   }
 
-  /** The multiplier by which the frame will scale horizontally, along the x-axis. */
-  public final float scaleX;
-  /** The multiplier by which the frame will scale vertically, along the y-axis. */
-  public final float scaleY;
-  /** How much to rotate the frame counterclockwise, in degrees. */
-  public final float rotationDegrees;
-
   private final Matrix transformationMatrix;
   private @MonotonicNonNull Matrix adjustedTransformationMatrix;
 
@@ -108,9 +101,6 @@ public final class ScaleToFitTransformation implements MatrixTransformation {
    * @param rotationDegrees How much to rotate the frame counterclockwise, in degrees.
    */
   private ScaleToFitTransformation(float scaleX, float scaleY, float rotationDegrees) {
-    this.scaleX = scaleX;
-    this.scaleY = scaleY;
-    this.rotationDegrees = rotationDegrees;
     transformationMatrix = new Matrix();
     transformationMatrix.postScale(scaleX, scaleY);
     transformationMatrix.postRotate(rotationDegrees);
@@ -160,4 +150,12 @@ public final class ScaleToFitTransformation implements MatrixTransformation {
   public Matrix getMatrix(long presentationTimeUs) {
     return checkStateNotNull(adjustedTransformationMatrix, "configure must be called first");
   }
+
+  @Override
+  public boolean isNoOp(int inputWidth, int inputHeight) {
+    Size outputSize = configure(inputWidth, inputHeight);
+    return checkStateNotNull(adjustedTransformationMatrix).isIdentity()
+        && inputWidth == outputSize.getWidth()
+        && inputHeight == outputSize.getHeight();
+  }
 }

library/effect/src/test/java/com/google/android/exoplayer2/effect/CropTest.java

@@ -37,7 +37,9 @@ public final class CropTest {
     Crop crop = new Crop(/* left= */ -1, /* right= */ 1, /* bottom= */ -1, /* top= */ 1);
 
     Size outputSize = crop.configure(inputWidth, inputHeight);
+    boolean isNoOp = crop.isNoOp(inputWidth, inputHeight);
 
+    assertThat(isNoOp).isTrue();
     assertThat(outputSize.getWidth()).isEqualTo(inputWidth);
     assertThat(outputSize.getHeight()).isEqualTo(inputHeight);
   }
@@ -53,7 +55,9 @@ public final class CropTest {
     Crop crop = new Crop(left, right, bottom, top);
 
     Size outputSize = crop.configure(inputWidth, inputHeight);
+    boolean isNoOp = crop.isNoOp(inputWidth, inputHeight);
 
+    assertThat(isNoOp).isFalse();
     int expectedPostCropWidth = Math.round(inputWidth * (right - left) / GlUtil.LENGTH_NDC);
     int expectedPostCropHeight = Math.round(inputHeight * (top - bottom) / GlUtil.LENGTH_NDC);
     assertThat(outputSize.getWidth()).isEqualTo(expectedPostCropWidth);

library/effect/src/test/java/com/google/android/exoplayer2/effect/PresentationTest.java

@@ -37,7 +37,9 @@ public final class PresentationTest {
     Presentation presentation = Presentation.createForHeight(C.LENGTH_UNSET);
 
     Size outputSize = presentation.configure(inputWidth, inputHeight);
+    boolean isNoOp = presentation.isNoOp(inputWidth, inputHeight);
 
+    assertThat(isNoOp).isTrue();
     assertThat(outputSize.getWidth()).isEqualTo(inputWidth);
     assertThat(outputSize.getHeight()).isEqualTo(inputHeight);
   }
@@ -50,7 +52,9 @@ public final class PresentationTest {
     Presentation presentation = Presentation.createForHeight(requestedHeight);
 
     Size outputSize = presentation.configure(inputWidth, inputHeight);
+    boolean isNoOp = presentation.isNoOp(inputWidth, inputHeight);
 
+    assertThat(isNoOp).isFalse();
     assertThat(outputSize.getWidth()).isEqualTo(requestedHeight * inputWidth / inputHeight);
     assertThat(outputSize.getHeight()).isEqualTo(requestedHeight);
   }
@@ -64,7 +68,9 @@ public final class PresentationTest {
         Presentation.createForAspectRatio(aspectRatio, Presentation.LAYOUT_SCALE_TO_FIT);
 
     Size outputSize = presentation.configure(inputWidth, inputHeight);
+    boolean isNoOp = presentation.isNoOp(inputWidth, inputHeight);
 
+    assertThat(isNoOp).isFalse();
     assertThat(outputSize.getWidth()).isEqualTo(Math.round(aspectRatio * inputHeight));
     assertThat(outputSize.getHeight()).isEqualTo(inputHeight);
   }
@@ -80,7 +86,9 @@ public final class PresentationTest {
             requestedWidth, requestedHeight, Presentation.LAYOUT_SCALE_TO_FIT);
 
     Size outputSize = presentation.configure(inputWidth, inputHeight);
+    boolean isNoOp = presentation.isNoOp(inputWidth, inputHeight);
 
+    assertThat(isNoOp).isFalse();
     assertThat(outputSize.getWidth()).isEqualTo(requestedWidth);
     assertThat(outputSize.getHeight()).isEqualTo(requestedHeight);
   }

library/effect/src/test/java/com/google/android/exoplayer2/effect/ScaleToFitTransformationTest.java

@@ -39,7 +39,9 @@ public final class ScaleToFitTransformationTest {
         new ScaleToFitTransformation.Builder().build();
 
     Size outputSize = scaleToFitTransformation.configure(inputWidth, inputHeight);
+    boolean isNoOp = scaleToFitTransformation.isNoOp(inputWidth, inputHeight);
 
+    assertThat(isNoOp).isTrue();
     assertThat(outputSize.getWidth()).isEqualTo(inputWidth);
     assertThat(outputSize.getHeight()).isEqualTo(inputHeight);
   }
@@ -54,7 +56,9 @@ public final class ScaleToFitTransformationTest {
             .build();
 
     Size outputSize = scaleToFitTransformation.configure(inputWidth, inputHeight);
+    boolean isNoOp = scaleToFitTransformation.isNoOp(inputWidth, inputHeight);
 
+    assertThat(isNoOp).isFalse();
     assertThat(outputSize.getWidth()).isEqualTo(Math.round(inputWidth * .5f));
     assertThat(outputSize.getHeight()).isEqualTo(inputHeight);
   }
@@ -67,7 +71,9 @@ public final class ScaleToFitTransformationTest {
         new ScaleToFitTransformation.Builder().setScale(/* scaleX= */ 2f, /* scaleY= */ 1f).build();
 
     Size outputSize = scaleToFitTransformation.configure(inputWidth, inputHeight);
+    boolean isNoOp = scaleToFitTransformation.isNoOp(inputWidth, inputHeight);
 
+    assertThat(isNoOp).isFalse();
     assertThat(outputSize.getWidth()).isEqualTo(inputWidth * 2);
     assertThat(outputSize.getHeight()).isEqualTo(inputHeight);
   }
@@ -80,7 +86,9 @@ public final class ScaleToFitTransformationTest {
         new ScaleToFitTransformation.Builder().setScale(/* scaleX= */ 1f, /* scaleY= */ 2f).build();
 
     Size outputSize = scaleToFitTransformation.configure(inputWidth, inputHeight);
+    boolean isNoOp = scaleToFitTransformation.isNoOp(inputWidth, inputHeight);
 
+    assertThat(isNoOp).isFalse();
     assertThat(outputSize.getWidth()).isEqualTo(inputWidth);
     assertThat(outputSize.getHeight()).isEqualTo(inputHeight * 2);
   }
@@ -93,7 +101,9 @@ public final class ScaleToFitTransformationTest {
         new ScaleToFitTransformation.Builder().setRotationDegrees(90).build();
 
     Size outputSize = scaleToFitTransformation.configure(inputWidth, inputHeight);
+    boolean isNoOp = scaleToFitTransformation.isNoOp(inputWidth, inputHeight);
 
+    assertThat(isNoOp).isFalse();
     assertThat(outputSize.getWidth()).isEqualTo(inputHeight);
     assertThat(outputSize.getHeight()).isEqualTo(inputWidth);
   }
@@ -107,7 +117,9 @@ public final class ScaleToFitTransformationTest {
     long expectedOutputWidthHeight = 247;
 
     Size outputSize = scaleToFitTransformation.configure(inputWidth, inputHeight);
+    boolean isNoOp = scaleToFitTransformation.isNoOp(inputWidth, inputHeight);
 
+    assertThat(isNoOp).isFalse();
     assertThat(outputSize.getWidth()).isEqualTo(expectedOutputWidthHeight);
     assertThat(outputSize.getHeight()).isEqualTo(expectedOutputWidthHeight);
   }

library/transformer/src/main/java/com/google/android/exoplayer2/transformer/TransformerInternal.java

@@ -32,8 +32,7 @@ import androidx.annotation.IntDef;
 import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
-import com.google.android.exoplayer2.effect.Presentation;
-import com.google.android.exoplayer2.effect.ScaleToFitTransformation;
+import com.google.android.exoplayer2.effect.GlEffect;
 import com.google.android.exoplayer2.metadata.Metadata;
 import com.google.android.exoplayer2.metadata.mp4.SlowMotionData;
 import com.google.android.exoplayer2.util.Clock;
@@ -42,7 +41,6 @@ import com.google.android.exoplayer2.util.DebugViewProvider;
 import com.google.android.exoplayer2.util.Effect;
 import com.google.android.exoplayer2.util.HandlerWrapper;
 import com.google.android.exoplayer2.util.MimeTypes;
-import com.google.android.exoplayer2.util.Size;
 import com.google.common.collect.ImmutableList;
 import java.lang.annotation.Documented;
 import java.lang.annotation.Retention;
@@ -565,35 +563,34 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
       if (inputFormat.pixelWidthHeightRatio != 1f) {
         return true;
       }
+      if (!areVideoEffectsAllNoOp(firstEditedMediaItem.effects.videoEffects, inputFormat)) {
+        return true;
+      }
+      return false;
+    }
 
-      // TODO(b/265927935): consider generalizing this logic.
-      for (int i = 0; i < firstEditedMediaItem.effects.videoEffects.size(); i++) {
-        Effect videoEffect = firstEditedMediaItem.effects.videoEffects.get(i);
-        if (videoEffect instanceof Presentation) {
-          Presentation presentation = (Presentation) videoEffect;
-          // The decoder rotates encoded frames for display by inputFormat.rotationDegrees.
-          int decodedWidth =
-              (inputFormat.rotationDegrees % 180 == 0) ? inputFormat.width : inputFormat.height;
-          int decodedHeight =
-              (inputFormat.rotationDegrees % 180 == 0) ? inputFormat.height : inputFormat.width;
-          Size outputSize = presentation.configure(decodedWidth, decodedHeight);
-          if (outputSize.getWidth() != decodedWidth || outputSize.getHeight() != decodedHeight) {
-            return true;
-          }
-        } else if (videoEffect instanceof ScaleToFitTransformation) {
-          ScaleToFitTransformation scaleToFitTransformation =
-              (ScaleToFitTransformation) videoEffect;
-          if (scaleToFitTransformation.scaleX != 1f
-              || scaleToFitTransformation.scaleY != 1f
-              || scaleToFitTransformation.rotationDegrees != 0f) {
-            return true;
-          }
-        } else {
-          return true;
+    /**
+     * Returns whether all {@code videoEffects} are {@linkplain GlEffect#isNoOp(int, int) no-ops},
+     * given an input {@link Format}.
+     */
+    private boolean areVideoEffectsAllNoOp(ImmutableList<Effect> videoEffects, Format inputFormat) {
+      int decodedWidth =
+          (inputFormat.rotationDegrees % 180 == 0) ? inputFormat.width : inputFormat.height;
+      int decodedHeight =
+          (inputFormat.rotationDegrees % 180 == 0) ? inputFormat.height : inputFormat.width;
+      for (int i = 0; i < videoEffects.size(); i++) {
+        Effect videoEffect = videoEffects.get(i);
+        if (!(videoEffect instanceof GlEffect)) {
+          // We cannot confirm whether Effect instances that are not GlEffect instances are
+          // no-ops.
+          return false;
+        }
+        GlEffect glEffect = (GlEffect) videoEffect;
+        if (!glEffect.isNoOp(decodedWidth, decodedHeight)) {
+          return false;
         }
       }
-
-      return false;
+      return true;
     }
   }
 }