Move generateSilentAudio to Composition

Also rename to forceAudioTrack

PiperOrigin-RevId: 510394620

demos/transformer/src/main/java/androidx/media3/demo/transformer/ConfigurationActivity.java

@@ -62,7 +62,7 @@ public final class ConfigurationActivity extends AppCompatActivity {
   public static final String SHOULD_REMOVE_AUDIO = "should_remove_audio";
   public static final String SHOULD_REMOVE_VIDEO = "should_remove_video";
   public static final String SHOULD_FLATTEN_FOR_SLOW_MOTION = "should_flatten_for_slow_motion";
-  public static final String GENERATE_SILENT_AUDIO = "generate_silent_audio";
+  public static final String FORCE_AUDIO_TRACK = "force_audio_track";
   public static final String AUDIO_MIME_TYPE = "audio_mime_type";
   public static final String VIDEO_MIME_TYPE = "video_mime_type";
   public static final String RESOLUTION_HEIGHT = "resolution_height";
@@ -213,7 +213,7 @@ public final class ConfigurationActivity extends AppCompatActivity {
   private @MonotonicNonNull CheckBox removeAudioCheckbox;
   private @MonotonicNonNull CheckBox removeVideoCheckbox;
   private @MonotonicNonNull CheckBox flattenForSlowMotionCheckbox;
-  private @MonotonicNonNull CheckBox generateSilentAudioCheckbox;
+  private @MonotonicNonNull CheckBox forceAudioTrackCheckbox;
   private @MonotonicNonNull Spinner audioMimeSpinner;
   private @MonotonicNonNull Spinner videoMimeSpinner;
   private @MonotonicNonNull Spinner resolutionHeightSpinner;
@@ -274,7 +274,7 @@ public final class ConfigurationActivity extends AppCompatActivity {
 
     flattenForSlowMotionCheckbox = findViewById(R.id.flatten_for_slow_motion_checkbox);
 
-    generateSilentAudioCheckbox = findViewById(R.id.generate_silent_audio_checkbox);
+    forceAudioTrackCheckbox = findViewById(R.id.force_audio_track_checkbox);
 
     ArrayAdapter<String> audioMimeAdapter =
         new ArrayAdapter<>(/* context= */ this, R.layout.spinner_item);
@@ -385,7 +385,7 @@ public final class ConfigurationActivity extends AppCompatActivity {
     "removeAudioCheckbox",
     "removeVideoCheckbox",
     "flattenForSlowMotionCheckbox",
-    "generateSilentAudioCheckbox",
+    "forceAudioTrackCheckbox",
     "audioMimeSpinner",
     "videoMimeSpinner",
     "resolutionHeightSpinner",
@@ -405,7 +405,7 @@ public final class ConfigurationActivity extends AppCompatActivity {
     bundle.putBoolean(SHOULD_REMOVE_AUDIO, removeAudioCheckbox.isChecked());
     bundle.putBoolean(SHOULD_REMOVE_VIDEO, removeVideoCheckbox.isChecked());
     bundle.putBoolean(SHOULD_FLATTEN_FOR_SLOW_MOTION, flattenForSlowMotionCheckbox.isChecked());
-    bundle.putBoolean(GENERATE_SILENT_AUDIO, generateSilentAudioCheckbox.isChecked());
+    bundle.putBoolean(FORCE_AUDIO_TRACK, forceAudioTrackCheckbox.isChecked());
     String selectedAudioMimeType = String.valueOf(audioMimeSpinner.getSelectedItem());
     if (!SAME_AS_INPUT_OPTION.equals(selectedAudioMimeType)) {
       bundle.putString(AUDIO_MIME_TYPE, selectedAudioMimeType);
@@ -739,7 +739,7 @@ public final class ConfigurationActivity extends AppCompatActivity {
 
   @RequiresNonNull({
     "removeVideoCheckbox",
-    "generateSilentAudioCheckbox",
+    "forceAudioTrackCheckbox",
     "audioMimeSpinner",
     "videoMimeSpinner",
     "resolutionHeightSpinner",
@@ -761,7 +761,7 @@ public final class ConfigurationActivity extends AppCompatActivity {
 
   @RequiresNonNull({
     "removeAudioCheckbox",
-    "generateSilentAudioCheckbox",
+    "forceAudioTrackCheckbox",
     "audioMimeSpinner",
     "videoMimeSpinner",
     "resolutionHeightSpinner",
@@ -782,7 +782,7 @@ public final class ConfigurationActivity extends AppCompatActivity {
   }
 
   @RequiresNonNull({
-    "generateSilentAudioCheckbox",
+    "forceAudioTrackCheckbox",
     "audioMimeSpinner",
     "videoMimeSpinner",
     "resolutionHeightSpinner",
@@ -794,7 +794,7 @@ public final class ConfigurationActivity extends AppCompatActivity {
     "selectVideoEffectsButton"
   })
   private void enableTrackSpecificOptions(boolean isAudioEnabled, boolean isVideoEnabled) {
-    generateSilentAudioCheckbox.setEnabled(isVideoEnabled);
+    forceAudioTrackCheckbox.setEnabled(isVideoEnabled);
     audioMimeSpinner.setEnabled(isAudioEnabled);
     videoMimeSpinner.setEnabled(isVideoEnabled);
     resolutionHeightSpinner.setEnabled(isVideoEnabled);

demos/transformer/src/main/java/androidx/media3/demo/transformer/TransformerActivity.java

@@ -82,6 +82,7 @@ import androidx.media3.transformer.Composition;
 import androidx.media3.transformer.DefaultEncoderFactory;
 import androidx.media3.transformer.DefaultMuxer;
 import androidx.media3.transformer.EditedMediaItem;
+import androidx.media3.transformer.EditedMediaItemSequence;
 import androidx.media3.transformer.Effects;
 import androidx.media3.transformer.ExportException;
 import androidx.media3.transformer.ExportResult;
@@ -99,6 +100,8 @@ import com.google.common.util.concurrent.ListenableFuture;
 import java.io.File;
 import java.io.IOException;
 import java.lang.reflect.Constructor;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
@@ -226,9 +229,9 @@ public final class TransformerActivity extends AppCompatActivity {
     MediaItem mediaItem = createMediaItem(bundle, uri);
     try {
       Transformer transformer = createTransformer(bundle, filePath);
-      EditedMediaItem editedMediaItem = createEditedMediaItem(mediaItem, bundle);
+      Composition composition = createComposition(mediaItem, bundle);
       exportStopwatch.start();
-      transformer.start(editedMediaItem, filePath);
+      transformer.start(composition, filePath);
       this.transformer = transformer;
     } catch (PackageManager.NameNotFoundException e) {
       throw new IllegalStateException(e);
@@ -300,13 +303,10 @@ public final class TransformerActivity extends AppCompatActivity {
       requestBuilder.setHdrMode(bundle.getInt(ConfigurationActivity.HDR_MODE));
       transformerBuilder.setTransformationRequest(requestBuilder.build());
 
-      transformerBuilder
+      transformerBuilder.setEncoderFactory(
-          .experimentalSetGenerateSilentAudio(
+          new DefaultEncoderFactory.Builder(this.getApplicationContext())
-              bundle.getBoolean(ConfigurationActivity.GENERATE_SILENT_AUDIO))
+              .setEnableFallback(bundle.getBoolean(ConfigurationActivity.ENABLE_FALLBACK))
-          .setEncoderFactory(
+              .build());
-              new DefaultEncoderFactory.Builder(this.getApplicationContext())
-                  .setEnableFallback(bundle.getBoolean(ConfigurationActivity.ENABLE_FALLBACK))
-                  .build());
 
       if (!bundle.getBoolean(ConfigurationActivity.ABORT_SLOW_EXPORT)) {
         transformerBuilder.setMuxerFactory(
@@ -357,23 +357,28 @@ public final class TransformerActivity extends AppCompatActivity {
     "exportStopwatch",
     "progressViewGroup",
   })
-  private EditedMediaItem createEditedMediaItem(MediaItem mediaItem, @Nullable Bundle bundle)
+  private Composition createComposition(MediaItem mediaItem, @Nullable Bundle bundle)
       throws PackageManager.NameNotFoundException {
     EditedMediaItem.Builder editedMediaItemBuilder = new EditedMediaItem.Builder(mediaItem);
-    if (bundle == null) {
-      return editedMediaItemBuilder.build();
-    }
     // For image inputs. Automatically ignored if input is audio/video.
     editedMediaItemBuilder.setDurationUs(5_000_000).setFrameRate(30);
-    ImmutableList<AudioProcessor> audioProcessors = createAudioProcessorsFromBundle(bundle);
+    boolean forceAudioTrack = false;
-    ImmutableList<Effect> videoEffects = createVideoEffectsFromBundle(bundle);
+    if (bundle != null) {
-    return editedMediaItemBuilder
+      ImmutableList<AudioProcessor> audioProcessors = createAudioProcessorsFromBundle(bundle);
-        .setRemoveAudio(bundle.getBoolean(ConfigurationActivity.SHOULD_REMOVE_AUDIO))
+      ImmutableList<Effect> videoEffects = createVideoEffectsFromBundle(bundle);
-        .setRemoveVideo(bundle.getBoolean(ConfigurationActivity.SHOULD_REMOVE_VIDEO))
+      editedMediaItemBuilder
-        .setFlattenForSlowMotion(
+          .setRemoveAudio(bundle.getBoolean(ConfigurationActivity.SHOULD_REMOVE_AUDIO))
-            bundle.getBoolean(ConfigurationActivity.SHOULD_FLATTEN_FOR_SLOW_MOTION))
+          .setRemoveVideo(bundle.getBoolean(ConfigurationActivity.SHOULD_REMOVE_VIDEO))
-        .setEffects(new Effects(audioProcessors, videoEffects))
+          .setFlattenForSlowMotion(
-        .build();
+              bundle.getBoolean(ConfigurationActivity.SHOULD_FLATTEN_FOR_SLOW_MOTION))
+          .setEffects(new Effects(audioProcessors, videoEffects));
+      forceAudioTrack = bundle.getBoolean(ConfigurationActivity.FORCE_AUDIO_TRACK);
+    }
+    List<EditedMediaItem> editedMediaItems = new ArrayList<>();
+    editedMediaItems.add(editedMediaItemBuilder.build());
+    List<EditedMediaItemSequence> sequences = new ArrayList<>();
+    sequences.add(new EditedMediaItemSequence(editedMediaItems));
+    return new Composition(sequences, Effects.EMPTY, forceAudioTrack);
   }
 
   private ImmutableList<AudioProcessor> createAudioProcessorsFromBundle(Bundle bundle) {

demos/transformer/src/main/res/layout/configuration_activity.xml

@@ -116,9 +116,9 @@
         android:layout_weight="1">
         <TextView
           android:layout_gravity="center_vertical"
-          android:text="@string/generate_silent_audio" />
+          android:text="@string/force_audio_track" />
         <CheckBox
-          android:id="@+id/generate_silent_audio_checkbox"
+          android:id="@+id/force_audio_track_checkbox"
           android:layout_gravity="end" />
       </TableRow>
       <TableRow

demos/transformer/src/main/res/values/strings.xml

@@ -67,7 +67,7 @@
   <string name="permission_denied">Permission Denied</string>
   <string name="hide_input_video">Hide input video</string>
   <string name="show_input_video">Show input video</string>
-  <string name="generate_silent_audio">Generate silent audio</string>
+  <string name="force_audio_track">Force audio track</string>
   <string name="overlay_alpha">Alpha</string>
   <string name="overlay_uri">Uri</string>
   <string name="bitmap_overlay_settings">Specify bitmap overlay settings</string>

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

@@ -66,16 +66,15 @@ import org.checkerframework.dataflow.qual.Pure;
       TransformationRequest transformationRequest,
       boolean flattenForSlowMotion,
       ImmutableList<AudioProcessor> audioProcessors,
-      long generateSilentAudioDurationUs,
+      long forceAudioTrackDurationUs,
       Codec.EncoderFactory encoderFactory,
       MuxerWrapper muxerWrapper,
       FallbackListener fallbackListener)
       throws ExportException {
     super(firstInputFormat, streamStartPositionUs, muxerWrapper);
 
-    if (generateSilentAudioDurationUs != C.TIME_UNSET) {
+    if (forceAudioTrackDurationUs != C.TIME_UNSET) {
-      silentAudioGenerator =
+      silentAudioGenerator = new SilentAudioGenerator(firstInputFormat, forceAudioTrackDurationUs);
-          new SilentAudioGenerator(firstInputFormat, generateSilentAudioDurationUs);
     } else {
       silentAudioGenerator = null;
     }

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

@@ -18,6 +18,7 @@ package androidx.media3.transformer;
 import static androidx.media3.common.util.Assertions.checkArgument;
 
 import androidx.media3.common.MediaItem;
+import androidx.media3.common.audio.AudioProcessor;
 import androidx.media3.common.util.UnstableApi;
 import com.google.common.collect.ImmutableList;
 import java.util.List;
@@ -40,16 +41,57 @@ public final class Composition {
   public final ImmutableList<EditedMediaItemSequence> sequences;
   /** The {@link Effects} to apply to the composition. */
   public final Effects effects;
+  /**
+   * Whether the output file should always contain an audio track.
+   *
+   * <ul>
+   *   <li>If {@code false}:
+   *       <ul>
+   *         <li>If the {@link Composition} export doesn't produce any audio at timestamp 0, the
+   *             output won't contain any audio, and audio tracks from the {@link MediaItem}
+   *             instances in the {@link Composition} will be ignored.
+   *         <li>If the {@link Composition} export produces audio at timestamp 0, the output will
+   *             contain an audio track.
+   *       </ul>
+   *   <li>If {@code true}, the output will always contain an audio track.
+   * </ul>
+   *
+   * If the output contains an audio track, silent audio will be generated for the segments where
+   * the {@link Composition} export doesn't produce any audio.
+   *
+   * <p>The MIME type of the output's audio track can be set using {@link
+   * TransformationRequest.Builder#setAudioMimeType(String)}. The sample rate and channel count can
+   * be set by passing relevant {@link AudioProcessor} instances to the {@link Composition}.
+   *
+   * <p>This parameter is experimental and may be removed or changed without warning.
+   */
+  public final boolean experimentalForceAudioTrack;
+
+  /**
+   * Creates an instance.
+   *
+   * <p>This is equivalent to calling {@link Composition#Composition(List, Effects, boolean)} with
+   * {@link #experimentalForceAudioTrack} set to {@code false}.
+   */
+  public Composition(List<EditedMediaItemSequence> sequences, Effects effects) {
+    this(sequences, effects, /* experimentalForceAudioTrack= */ false);
+  }
 
   /**
    * Creates an instance.
    *
    * @param sequences The {@link #sequences}.
    * @param effects The {@link #effects}.
+   * @param experimentalForceAudioTrack Whether to {@linkplain #experimentalForceAudioTrack always
+   *     add an audio track in the output}.
    */
-  public Composition(List<EditedMediaItemSequence> sequences, Effects effects) {
+  public Composition(
+      List<EditedMediaItemSequence> sequences,
+      Effects effects,
+      boolean experimentalForceAudioTrack) {
     checkArgument(!sequences.isEmpty());
     this.sequences = ImmutableList.copyOf(sequences);
     this.effects = effects;
+    this.experimentalForceAudioTrack = experimentalForceAudioTrack;
   }
 }

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

@@ -33,7 +33,6 @@ import androidx.media3.common.MediaLibraryInfo;
 import androidx.media3.common.MimeTypes;
 import androidx.media3.common.VideoFrameProcessor;
 import androidx.media3.common.audio.AudioProcessor;
-import androidx.media3.common.audio.SonicAudioProcessor;
 import androidx.media3.common.util.Clock;
 import androidx.media3.common.util.HandlerWrapper;
 import androidx.media3.common.util.ListenerSet;
@@ -86,7 +85,6 @@ public final class Transformer {
     private boolean removeVideo;
     private boolean flattenForSlowMotion;
     private boolean transmux;
-    private boolean generateSilentAudio;
     private ListenerSet<Transformer.Listener> listeners;
     private AssetLoader.@MonotonicNonNull Factory assetLoaderFactory;
     private VideoFrameProcessor.Factory videoFrameProcessorFactory;
@@ -123,7 +121,6 @@ public final class Transformer {
       this.videoEffects = transformer.videoEffects;
       this.removeAudio = transformer.removeAudio;
       this.removeVideo = transformer.removeVideo;
-      this.generateSilentAudio = transformer.generateSilentAudio;
       this.listeners = transformer.listeners;
       this.assetLoaderFactory = transformer.assetLoaderFactory;
       this.videoFrameProcessorFactory = transformer.videoFrameProcessorFactory;
@@ -395,39 +392,6 @@ public final class Transformer {
       return this;
     }
 
-    /**
-     * Sets whether to generate silent audio for the output file, if there is no audio available.
-     *
-     * <p>This method is experimental and may be removed or changed without warning.
-     *
-     * <p>To replace existing audio with silence, {@linkplain
-     * EditedMediaItem.Builder#setRemoveAudio(boolean) remove the audio} from the {@link
-     * EditedMediaItem} to export.
-     *
-     * <p>Audio properties/format:
-     *
-     * <ul>
-     *   <li>Duration will match duration of the input media.
-     *   <li>Sample mime type will match {@link TransformationRequest#audioMimeType}, or {@link
-     *       MimeTypes#AUDIO_AAC} if {@code null}.
-     *   <li>Sample rate will be {@code 44100} Hz. This can be modified by creating a {@link
-     *       SonicAudioProcessor}, setting its {@linkplain
-     *       SonicAudioProcessor#setOutputSampleRateHz(int) sample rate}, and passing it to the
-     *       {@link EditedMediaItem} used to start the export.
-     *   <li>Channel count will be {@code 2}. This can be modified by implementing a custom {@link
-     *       AudioProcessor} and passing it to the {@link EditedMediaItem} used to start the export.
-     * </ul>
-     *
-     * @param generateSilentAudio Whether to generate silent audio for the output file if there is
-     *     no audio track.
-     * @return This builder.
-     */
-    @CanIgnoreReturnValue
-    public Builder experimentalSetGenerateSilentAudio(boolean generateSilentAudio) {
-      this.generateSilentAudio = generateSilentAudio;
-      return this;
-    }
-
     /**
      * Builds a {@link Transformer} instance.
      *
@@ -461,7 +425,6 @@ public final class Transformer {
           removeVideo,
           flattenForSlowMotion,
           transmux,
-          generateSilentAudio,
           listeners,
           assetLoaderFactory,
           videoFrameProcessorFactory,
@@ -620,7 +583,6 @@ public final class Transformer {
   private final boolean removeVideo;
   private final boolean flattenForSlowMotion;
   private final boolean transmux;
-  private final boolean generateSilentAudio;
   private final ListenerSet<Transformer.Listener> listeners;
   private final AssetLoader.Factory assetLoaderFactory;
   private final VideoFrameProcessor.Factory videoFrameProcessorFactory;
@@ -641,7 +603,6 @@ public final class Transformer {
       boolean removeVideo,
       boolean flattenForSlowMotion,
       boolean transmux,
-      boolean generateSilentAudio,
       ListenerSet<Listener> listeners,
       AssetLoader.Factory assetLoaderFactory,
       VideoFrameProcessor.Factory videoFrameProcessorFactory,
@@ -659,7 +620,6 @@ public final class Transformer {
     this.removeVideo = removeVideo;
     this.flattenForSlowMotion = flattenForSlowMotion;
     this.transmux = transmux;
-    this.generateSilentAudio = generateSilentAudio;
     this.listeners = listeners;
     this.assetLoaderFactory = assetLoaderFactory;
     this.videoFrameProcessorFactory = videoFrameProcessorFactory;
@@ -779,7 +739,6 @@ public final class Transformer {
             path,
             transformationRequest,
             transmux,
-            generateSilentAudio,
             assetLoaderFactory,
             encoderFactory,
             muxerFactory,

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

@@ -100,7 +100,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
   private final ConditionVariable transformerConditionVariable;
   private final ExportResult.Builder exportResultBuilder;
 
-  private boolean generateSilentAudio;
+  private boolean forceAudioTrack;
   private boolean isDrainingPipelines;
   private @Transformer.ProgressState int progressState;
   private @MonotonicNonNull RuntimeException cancelException;
@@ -113,7 +113,6 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
       String outputPath,
       TransformationRequest transformationRequest,
       boolean transmux,
-      boolean generateSilentAudio,
       AssetLoader.Factory assetLoaderFactory,
       Codec.EncoderFactory encoderFactory,
       Muxer.Factory muxerFactory,
@@ -124,7 +123,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
       Clock clock) {
     this.context = context;
     this.transformationRequest = transformationRequest;
-    this.generateSilentAudio = generateSilentAudio;
+    this.forceAudioTrack = composition.experimentalForceAudioTrack;
     this.encoderFactory = new CapturingEncoderFactory(encoderFactory);
     this.listener = listener;
     this.applicationHandler = applicationHandler;
@@ -366,11 +365,11 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
         throws ExportException {
       int trackType = MimeTypes.getTrackType(firstInputFormat.sampleMimeType);
       if (!trackAdded) {
-        if (generateSilentAudio) {
+        if (forceAudioTrack) {
           if (trackCount.get() == 1 && trackType == C.TRACK_TYPE_VIDEO) {
             trackCount.incrementAndGet();
           } else {
-            generateSilentAudio = false;
+            forceAudioTrack = false;
           }
         }
 
@@ -387,7 +386,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
       compositeAssetLoader.addOnMediaItemChangedListener(samplePipeline, trackType);
       internalHandler.obtainMessage(MSG_REGISTER_SAMPLE_PIPELINE, samplePipeline).sendToTarget();
 
-      if (generateSilentAudio) {
+      if (forceAudioTrack) {
         Format silentAudioFormat =
             new Format.Builder()
                 .setSampleMimeType(MimeTypes.AUDIO_AAC)
@@ -479,7 +478,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
             transformationRequest,
             firstEditedMediaItem.flattenForSlowMotion,
             firstEditedMediaItem.effects.audioProcessors,
-            generateSilentAudio ? durationUs : C.TIME_UNSET,
+            forceAudioTrack ? durationUs : C.TIME_UNSET,
             encoderFactory,
             muxerWrapper,
             fallbackListener);
@@ -525,7 +524,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
       if (!firstEditedMediaItem.effects.audioProcessors.isEmpty()) {
         return true;
       }
-      if (generateSilentAudio) {
+      if (forceAudioTrack) {
         return true;
       }
 

libraries/transformer/src/test/java/androidx/media3/transformer/TransformerEndToEndTest.java

@@ -279,14 +279,17 @@ public final class TransformerEndToEndTest {
   }
 
   @Test
-  public void start_silentAudioOnAudioOnly_isIgnored() throws Exception {
+  public void start_forceAudioTrackOnAudioOnly_isIgnored() throws Exception {
-    Transformer transformer =
+    Transformer transformer = createTransformerBuilder(/* enableFallback= */ false).build();
-        createTransformerBuilder(/* enableFallback= */ false)
-            .experimentalSetGenerateSilentAudio(true)
-            .build();
     MediaItem mediaItem = MediaItem.fromUri(ASSET_URI_PREFIX + FILE_AUDIO_UNSUPPORTED_BY_ENCODER);
+    EditedMediaItem editedMediaItem = new EditedMediaItem.Builder(mediaItem).build();
+    EditedMediaItemSequence sequence =
+        new EditedMediaItemSequence(ImmutableList.of(editedMediaItem));
+    Composition composition =
+        new Composition(
+            ImmutableList.of(sequence), Effects.EMPTY, /* experimentalForceAudioTrack= */ true);
 
-    transformer.start(mediaItem, outputPath);
+    transformer.start(composition, outputPath);
     TransformerTestRunner.runLooper(transformer);
 
     DumpFileAsserts.assertOutput(
@@ -294,31 +297,36 @@ public final class TransformerEndToEndTest {
   }
 
   @Test
-  public void start_silentAudioOnAudioVideo_isIgnored() throws Exception {
+  public void start_forceAudioTrackOnAudioVideo_isIgnored() throws Exception {
-    Transformer transformer =
+    Transformer transformer = createTransformerBuilder(/* enableFallback= */ false).build();
-        createTransformerBuilder(/* enableFallback= */ false)
-            .experimentalSetGenerateSilentAudio(true)
-            .build();
     MediaItem mediaItem = MediaItem.fromUri(ASSET_URI_PREFIX + FILE_AUDIO_VIDEO);
+    EditedMediaItem editedMediaItem = new EditedMediaItem.Builder(mediaItem).build();
+    EditedMediaItemSequence sequence =
+        new EditedMediaItemSequence(ImmutableList.of(editedMediaItem));
+    Composition composition =
+        new Composition(
+            ImmutableList.of(sequence), Effects.EMPTY, /* experimentalForceAudioTrack= */ true);
 
-    transformer.start(mediaItem, outputPath);
+    transformer.start(composition, outputPath);
     TransformerTestRunner.runLooper(transformer);
 
     DumpFileAsserts.assertOutput(context, testMuxer, getDumpFileName(FILE_AUDIO_VIDEO));
   }
 
   @Test
-  public void start_silentAudioRemoveAudio_completesSuccessfully() throws Exception {
+  public void start_forceAudioTrackAndRemoveAudio_generatesSilentAudio() throws Exception {
-    Transformer transformer =
+    Transformer transformer = createTransformerBuilder(/* enableFallback= */ false).build();
-        createTransformerBuilder(/* enableFallback= */ false)
-            .experimentalSetGenerateSilentAudio(true)
-            .build();
     EditedMediaItem editedMediaItem =
         new EditedMediaItem.Builder(MediaItem.fromUri(ASSET_URI_PREFIX + FILE_AUDIO_VIDEO))
             .setRemoveAudio(true)
             .build();
+    EditedMediaItemSequence sequence =
+        new EditedMediaItemSequence(ImmutableList.of(editedMediaItem));
+    Composition composition =
+        new Composition(
+            ImmutableList.of(sequence), Effects.EMPTY, /* experimentalForceAudioTrack= */ true);
 
-    transformer.start(editedMediaItem, outputPath);
+    transformer.start(composition, outputPath);
     TransformerTestRunner.runLooper(transformer);
 
     DumpFileAsserts.assertOutput(
@@ -326,31 +334,36 @@ public final class TransformerEndToEndTest {
   }
 
   @Test
-  public void start_silentAudioRemoveVideo_isIgnored() throws Exception {
+  public void start_forceAudioTrackAndRemoveVideo_isIgnored() throws Exception {
-    Transformer transformer =
+    Transformer transformer = createTransformerBuilder(/* enableFallback= */ false).build();
-        createTransformerBuilder(/* enableFallback= */ false)
-            .experimentalSetGenerateSilentAudio(true)
-            .build();
     EditedMediaItem editedMediaItem =
         new EditedMediaItem.Builder(MediaItem.fromUri(ASSET_URI_PREFIX + FILE_AUDIO_VIDEO))
             .setRemoveVideo(true)
             .build();
+    EditedMediaItemSequence sequence =
+        new EditedMediaItemSequence(ImmutableList.of(editedMediaItem));
+    Composition composition =
+        new Composition(
+            ImmutableList.of(sequence), Effects.EMPTY, /* experimentalForceAudioTrack= */ true);
 
-    transformer.start(editedMediaItem, outputPath);
+    transformer.start(composition, outputPath);
     TransformerTestRunner.runLooper(transformer);
     DumpFileAsserts.assertOutput(
         context, testMuxer, getDumpFileName(FILE_AUDIO_VIDEO + ".novideo"));
   }
 
   @Test
-  public void start_silentAudioOnVideoOnly_completesSuccessfully() throws Exception {
+  public void start_forceAudioTrackOnVideoOnly_generatesSilentAudio() throws Exception {
-    Transformer transformer =
+    Transformer transformer = createTransformerBuilder(/* enableFallback= */ false).build();
-        createTransformerBuilder(/* enableFallback= */ false)
-            .experimentalSetGenerateSilentAudio(true)
-            .build();
     MediaItem mediaItem = MediaItem.fromUri(ASSET_URI_PREFIX + FILE_VIDEO_ONLY);
+    EditedMediaItem editedMediaItem = new EditedMediaItem.Builder(mediaItem).build();
+    EditedMediaItemSequence sequence =
+        new EditedMediaItemSequence(ImmutableList.of(editedMediaItem));
+    Composition composition =
+        new Composition(
+            ImmutableList.of(sequence), Effects.EMPTY, /* experimentalForceAudioTrack= */ true);
 
-    transformer.start(mediaItem, outputPath);
+    transformer.start(composition, outputPath);
     TransformerTestRunner.runLooper(transformer);
 
     DumpFileAsserts.assertOutput(