Use CompositeAssetLoader in Transformer

PiperOrigin-RevId: 506863538

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

@@ -57,12 +57,12 @@ import java.util.concurrent.atomic.AtomicLong;
   private volatile long currentDurationUs;
 
   public CompositeAssetLoader(
-      List<EditedMediaItem> editedMediaItems,
+      EditedMediaItemSequence sequence,
       AssetLoader.Factory assetLoaderFactory,
       Looper looper,
       Listener listener,
       Clock clock) {
-    this.editedMediaItems = editedMediaItems;
+    this.editedMediaItems = sequence.editedMediaItems;
     this.assetLoaderFactory = assetLoaderFactory;
     compositeAssetLoaderListener = listener;
     currentMediaItemIndex = new AtomicInteger();

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

@@ -15,6 +15,8 @@
  */
 package com.google.android.exoplayer2.transformer;
 
+import static com.google.android.exoplayer2.util.Assertions.checkArgument;
+
 import com.google.android.exoplayer2.MediaItem;
 import com.google.common.collect.ImmutableList;
 
@@ -29,6 +31,8 @@ public final class Composition {
   /**
    * The {@link EditedMediaItemSequence} instances to compose. {@link MediaItem} instances from
    * different sequences that are overlapping in time will be mixed in the output.
+   *
+   * <p>This list must not be empty.
    */
   public final ImmutableList<EditedMediaItemSequence> sequences;
   /** The {@link Effects} to apply to the composition. */
@@ -41,6 +45,7 @@ public final class Composition {
    * @param effects The {@link #effects}.
    */
   public Composition(ImmutableList<EditedMediaItemSequence> sequences, Effects effects) {
+    checkArgument(!sequences.isEmpty());
     this.sequences = sequences;
     this.effects = effects;
   }

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

@@ -15,6 +15,8 @@
  */
 package com.google.android.exoplayer2.transformer;
 
+import static com.google.android.exoplayer2.util.Assertions.checkArgument;
+
 import com.google.common.collect.ImmutableList;
 
 /**
@@ -24,7 +26,11 @@ import com.google.common.collect.ImmutableList;
  */
 public final class EditedMediaItemSequence {
 
-  /** The {@link EditedMediaItem} instances in the sequence. */
+  /**
+   * The {@link EditedMediaItem} instances in the sequence.
+   *
+   * <p>This list must not be empty.
+   */
   public final ImmutableList<EditedMediaItem> editedMediaItems;
 
   /**
@@ -33,6 +39,7 @@ public final class EditedMediaItemSequence {
    * @param editedMediaItems The {@link #editedMediaItems}.
    */
   public EditedMediaItemSequence(ImmutableList<EditedMediaItem> editedMediaItems) {
+    checkArgument(!editedMediaItems.isEmpty());
     this.editedMediaItems = editedMediaItems;
   }
 }

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

@@ -761,7 +761,7 @@ public final class Transformer {
     transformerInternal =
         new TransformerInternal(
             context,
-            editedMediaItem,
+            composition,
             path,
             transformationRequest,
             generateSilentAudio,

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

@@ -111,7 +111,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
 
   public TransformerInternal(
       Context context,
-      EditedMediaItem editedMediaItem,
+      Composition composition,
       String outputPath,
       TransformationRequest transformationRequest,
       boolean generateSilentAudio,
@@ -134,9 +134,11 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
     internalHandlerThread = new HandlerThread("Transformer:Internal");
     internalHandlerThread.start();
     Looper internalLooper = internalHandlerThread.getLooper();
-    ComponentListener componentListener = new ComponentListener(editedMediaItem, fallbackListener);
+    EditedMediaItemSequence sequence = composition.sequences.get(0);
+    ComponentListener componentListener = new ComponentListener(sequence, fallbackListener);
     assetLoader =
-        assetLoaderFactory.createAssetLoader(editedMediaItem, internalLooper, componentListener);
+        new CompositeAssetLoader(
+            sequence, assetLoaderFactory, internalLooper, componentListener, clock);
     samplePipelines = new ArrayList<>();
     muxerWrapper = new MuxerWrapper(outputPath, muxerFactory, componentListener);
     transformerConditionVariable = new ConditionVariable();
@@ -313,7 +315,8 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
 
   private class ComponentListener implements AssetLoader.Listener, MuxerWrapper.Listener {
 
-    private final EditedMediaItem editedMediaItem;
+    // The first EditedMediaItem in the sequence determines which SamplePipeline to use.
+    private final EditedMediaItem firstEditedMediaItem;
     private final FallbackListener fallbackListener;
     private final AtomicInteger trackCount;
 
@@ -321,8 +324,8 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
 
     private volatile long durationUs;
 
-    public ComponentListener(EditedMediaItem editedMediaItem, FallbackListener fallbackListener) {
-      this.editedMediaItem = editedMediaItem;
+    public ComponentListener(EditedMediaItemSequence sequence, FallbackListener fallbackListener) {
+      firstEditedMediaItem = sequence.editedMediaItems.get(0);
       this.fallbackListener = fallbackListener;
       trackCount = new AtomicInteger();
       durationUs = C.TIME_UNSET;
@@ -468,8 +471,8 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
             streamStartPositionUs,
             streamOffsetUs,
             transformationRequest,
-            editedMediaItem.flattenForSlowMotion,
-            editedMediaItem.effects.audioProcessors,
+            firstEditedMediaItem.flattenForSlowMotion,
+            firstEditedMediaItem.effects.audioProcessors,
             generateSilentAudio ? durationUs : C.TIME_UNSET,
             encoderFactory,
             muxerWrapper,
@@ -481,8 +484,8 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
             streamStartPositionUs,
             streamOffsetUs,
             transformationRequest,
-            editedMediaItem.effects.videoEffects,
-            editedMediaItem.effects.frameProcessorFactory,
+            firstEditedMediaItem.effects.videoEffects,
+            firstEditedMediaItem.effects.frameProcessorFactory,
             encoderFactory,
             muxerWrapper,
             /* errorConsumer= */ this::onTransformationError,
@@ -510,10 +513,10 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
           && !muxerWrapper.supportsSampleMimeType(inputFormat.sampleMimeType)) {
         return true;
       }
-      if (editedMediaItem.flattenForSlowMotion && isSlowMotion(inputFormat)) {
+      if (firstEditedMediaItem.flattenForSlowMotion && isSlowMotion(inputFormat)) {
         return true;
       }
-      if (!editedMediaItem.effects.audioProcessors.isEmpty()) {
+      if (!firstEditedMediaItem.effects.audioProcessors.isEmpty()) {
         return true;
       }
       if (generateSilentAudio) {
@@ -539,7 +542,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
     private boolean shouldTranscodeVideo(
         Format inputFormat, long streamStartPositionUs, long streamOffsetUs) {
       if ((streamStartPositionUs - streamOffsetUs) != 0
-          && !editedMediaItem.mediaItem.clippingConfiguration.startsAtKeyFrame) {
+          && !firstEditedMediaItem.mediaItem.clippingConfiguration.startsAtKeyFrame) {
         return true;
       }
       if (encoderFactory.videoNeedsEncoding()) {
@@ -561,8 +564,8 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
       }
 
       // TODO(b/265927935): consider generalizing this logic.
-      for (int i = 0; i < editedMediaItem.effects.videoEffects.size(); i++) {
-        Effect videoEffect = editedMediaItem.effects.videoEffects.get(i);
+      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.