Transformer: add speedChange API

PiperOrigin-RevId: 616163061

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

@@ -52,6 +52,7 @@ import android.os.Handler;
 import android.os.HandlerThread;
 import android.os.Looper;
 import android.os.Message;
+import android.util.Pair;
 import androidx.media3.common.C;
 import androidx.media3.common.Effect;
 import androidx.media3.common.Format;
@@ -64,6 +65,7 @@ import androidx.media3.common.audio.AudioProcessor.AudioFormat;
 import androidx.media3.common.audio.ChannelMixingAudioProcessor;
 import androidx.media3.common.audio.ChannelMixingMatrix;
 import androidx.media3.common.audio.SonicAudioProcessor;
+import androidx.media3.common.audio.SpeedProvider;
 import androidx.media3.common.util.GlUtil;
 import androidx.media3.common.util.Util;
 import androidx.media3.datasource.DataSourceBitmapLoader;
@@ -81,6 +83,7 @@ import androidx.media3.extractor.mp4.Mp4Extractor;
 import androidx.media3.extractor.text.DefaultSubtitleParserFactory;
 import androidx.media3.test.utils.FakeExtractorOutput;
 import androidx.media3.test.utils.FakeTrackOutput;
+import androidx.media3.test.utils.TestSpeedProvider;
 import androidx.media3.test.utils.TestUtil;
 import androidx.media3.transformer.AssetLoader.CompositionSettings;
 import androidx.test.core.app.ApplicationProvider;
@@ -868,6 +871,40 @@ public class TransformerEndToEndTest {
     assertThat(result.exportResult.audioConversionProcess).isEqualTo(CONVERSION_PROCESS_TRANSMUXED);
   }
 
+  @Test
+  public void speedAdjustedMedia_completesWithCorrectDuration() throws Exception {
+    Transformer transformer = new Transformer.Builder(context).build();
+    SpeedProvider speedProvider =
+        TestSpeedProvider.createWithStartTimes(
+            new long[] {
+              0L,
+              3 * C.MICROS_PER_SECOND,
+              6 * C.MICROS_PER_SECOND,
+              9 * C.MICROS_PER_SECOND,
+              12 * C.MICROS_PER_SECOND
+            },
+            new float[] {0.5f, 0.75f, 1f, 1.5f, 2f});
+    Pair<AudioProcessor, Effect> speedEffect =
+        Effects.createExperimentalSpeedChangingEffect(speedProvider);
+    Effects effects =
+        new Effects(
+            /* audioProcessors= */ ImmutableList.of(speedEffect.first),
+            /* videoEffects= */ ImmutableList.of(speedEffect.second));
+    EditedMediaItem editedMediaItem =
+        new EditedMediaItem.Builder(
+                MediaItem.fromUri(MP4_ASSET_WITH_INCREASING_TIMESTAMPS_320W_240H_15S_URI_STRING))
+            .setEffects(effects)
+            .build();
+    ExportTestResult result =
+        new TransformerAndroidTestRunner.Builder(context, transformer)
+            .build()
+            .run(testId, editedMediaItem);
+
+    // The input video is 15.537 seconds.
+    // 3 / 0.5 + 3 / 0.75 + 3 + 3 / 1.5 + 3.537 / 2 rounds up to 16_770
+    assertThat(result.exportResult.durationMs).isAtMost(16_770);
+  }
+
   @Test
   public void videoEncoderFormatUnsupported_completesWithError() throws Exception {
     if (AndroidTestUtil.skipAndLogIfFormatsUnsupported(

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

@@ -15,10 +15,15 @@
  */
 package androidx.media3.transformer;
 
+import android.util.Pair;
 import androidx.media3.common.Effect;
 import androidx.media3.common.MediaItem;
 import androidx.media3.common.audio.AudioProcessor;
+import androidx.media3.common.audio.SpeedChangingAudioProcessor;
+import androidx.media3.common.audio.SpeedProvider;
 import androidx.media3.common.util.UnstableApi;
+import androidx.media3.effect.SpeedChangeEffect;
+import androidx.media3.effect.TimestampAdjustment;
 import com.google.common.collect.ImmutableList;
 import java.util.List;
 
@@ -54,4 +59,28 @@ public final class Effects {
     this.audioProcessors = ImmutableList.copyOf(audioProcessors);
     this.videoEffects = ImmutableList.copyOf(videoEffects);
   }
+
+  /**
+   * Creates an interlinked {@linkplain AudioProcessor audio processor} and {@linkplain Effect video
+   * effect} that changes the speed to media samples in segments of the input file specified by the
+   * given {@link SpeedProvider}.
+   *
+   * <p>The {@linkplain AudioProcessor audio processor} and {@linkplain Effect video effect} are
+   * interlinked to help maintain A/V sync. When using Transformer, if the input file doesn't have
+   * audio, or audio is being removed, you may have to {@linkplain
+   * Composition.Builder#experimentalSetForceAudioTrack force an audio track} for the interlinked
+   * effects to function correctly. Alternatively, you can use {@link SpeedChangeEffect} when input
+   * has no audio.
+   *
+   * @param speedProvider The {@link SpeedProvider} determining the speed for the media at specific
+   *     timestamps.
+   */
+  public static Pair<AudioProcessor, Effect> createExperimentalSpeedChangingEffect(
+      SpeedProvider speedProvider) {
+    SpeedChangingAudioProcessor speedChangingAudioProcessor =
+        new SpeedChangingAudioProcessor(speedProvider);
+    Effect audioDrivenvideoEffect =
+        new TimestampAdjustment(speedChangingAudioProcessor::getSpeedAdjustedTimeAsync);
+    return Pair.create(speedChangingAudioProcessor, audioDrivenvideoEffect);
+  }
 }