Make defensive copies of the transformation matrix.

TransformationRequest is otherwise immutable, so if we modify the
transformationMatrix in place (done before this cl) this may cause
confusing behaviour for apps when they reuse a TransformationRequest.

PiperOrigin-RevId: 422822916

libraries/transformer/src/main/java/androidx/media3/transformer/TransformationRequest.java

@@ -56,7 +56,7 @@ public final class TransformationRequest {
     }
 
     private Builder(TransformationRequest transformationRequest) {
-      this.transformationMatrix = transformationRequest.transformationMatrix;
+      this.transformationMatrix = new Matrix(transformationRequest.transformationMatrix);
       this.flattenForSlowMotion = transformationRequest.flattenForSlowMotion;
       this.outputHeight = transformationRequest.outputHeight;
       this.audioMimeType = transformationRequest.audioMimeType;
@@ -86,7 +86,7 @@ public final class TransformationRequest {
       // TODO(b/213198690): Consider changing how transformationMatrix is applied, so that
       // dimensions will be from -1 to 1 on both x and y axes, but transformations will be applied
       // in a predictable manner.
-      this.transformationMatrix = transformationMatrix;
+      this.transformationMatrix = new Matrix(transformationMatrix);
       return this;
     }
 

libraries/transformer/src/main/java/androidx/media3/transformer/VideoSamplePipeline.java

@@ -20,6 +20,7 @@ import static androidx.media3.common.util.Assertions.checkNotNull;
 import static androidx.media3.common.util.Util.SDK_INT;
 
 import android.content.Context;
+import android.graphics.Matrix;
 import android.media.MediaCodec;
 import android.media.MediaFormat;
 import androidx.annotation.Nullable;
@@ -87,18 +88,19 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
             ? inputFormatAspectRatio
             : 1.0f / inputFormatAspectRatio;
 
+    Matrix transformationMatrix = new Matrix(transformationRequest.transformationMatrix);
     // Scale frames by input aspect ratio, to account for FrameEditor's square normalized device
     // coordinates (-1 to 1) and preserve frame relative dimensions during transformations
     // (ex. rotations). After this scaling, transformationMatrix operations operate on a rectangle
     // for x from -displayAspectRatio to displayAspectRatio, and y from -1 to 1
-    transformationRequest.transformationMatrix.preScale(displayAspectRatio, 1);
-    transformationRequest.transformationMatrix.postScale(1.0f / displayAspectRatio, 1);
+    transformationMatrix.preScale(displayAspectRatio, 1);
+    transformationMatrix.postScale(1.0f / displayAspectRatio, 1);
 
     // The decoder rotates videos to their intended display orientation. The frameEditor rotates
     // them back for improved encoder compatibility.
     // TODO(b/201293185): After fragment shader transformations are implemented, put
     // postRotate in a later vertex shader.
-    transformationRequest.transformationMatrix.postRotate(outputRotationDegrees);
+    transformationMatrix.postRotate(outputRotationDegrees);
 
     encoder =
         encoderFactory.createForVideoEncoding(
@@ -113,17 +115,18 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
                 .build());
     if (inputFormat.height != outputHeight
         || inputFormat.width != outputWidth
-        || !transformationRequest.transformationMatrix.isIdentity()) {
+        || !transformationMatrix.isIdentity()) {
       frameEditor =
           FrameEditor.create(
               context,
               outputWidth,
               outputHeight,
               inputFormat.pixelWidthHeightRatio,
-              transformationRequest.transformationMatrix,
+              transformationMatrix,
               /* outputSurface= */ checkNotNull(encoder.getInputSurface()),
               debugViewProvider);
     }
+
     decoder =
         decoderFactory.createForVideoDecoding(
             inputFormat,