Only init SpeedChangingAudioProcessor if Format.Metadata not null.

If the Metadata passed to SegmentSpeedProvider is null, then the
SegmentSpeedProvider will always return 1f from getSpeed.

Initializing a SpeedChangingAudioProcessor requires a SpeedProvider.
Once configured,this audioProcessor is always active, so buffers are
passed through it. Because getSpeed is always 1, the processor performs
a no-op, but still has to do a buffer copy for each buffer.

By not initializing the audio processor when metadata is null, this
copy can be skipped and the audio pipeline is more performant.

Note: This change does not affect the multiple media-item case, which
is not supported with speed changes, as per Transformer API
documentation.
PiperOrigin-RevId: 513261811

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

@@ -84,10 +84,12 @@ import org.checkerframework.dataflow.qual.Pure;
     encoderInputBuffer = new DecoderInputBuffer(BUFFER_REPLACEMENT_MODE_DISABLED);
     encoderOutputBuffer = new DecoderInputBuffer(BUFFER_REPLACEMENT_MODE_DISABLED);
 
-    if (flattenForSlowMotion) {
+    if (flattenForSlowMotion && firstInputFormat.metadata != null) {
       audioProcessors =
           new ImmutableList.Builder<AudioProcessor>()
-              .add(new SpeedChangingAudioProcessor(new SegmentSpeedProvider(firstInputFormat)))
+              .add(
+                  new SpeedChangingAudioProcessor(
+                      new SegmentSpeedProvider(firstInputFormat.metadata)))
               .addAll(audioProcessors)
               .build();
     }

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

@@ -20,7 +20,6 @@ import static androidx.media3.extractor.metadata.mp4.SlowMotionData.Segment.BY_S
 
 import androidx.annotation.Nullable;
 import androidx.media3.common.C;
-import androidx.media3.common.Format;
 import androidx.media3.common.Metadata;
 import androidx.media3.common.util.Util;
 import androidx.media3.extractor.metadata.mp4.SlowMotionData;
@@ -45,11 +44,11 @@ import java.util.TreeMap;
   private final ImmutableSortedMap<Long, Float> speedsByStartTimeUs;
   private final float baseSpeedMultiplier;
 
-  public SegmentSpeedProvider(Format format) {
+  public SegmentSpeedProvider(Metadata metadata) {
-    float captureFrameRate = getCaptureFrameRate(format);
+    float captureFrameRate = getCaptureFrameRate(metadata);
     this.baseSpeedMultiplier =
         captureFrameRate == C.RATE_UNSET ? 1 : captureFrameRate / INPUT_FRAME_RATE;
-    this.speedsByStartTimeUs = buildSpeedByStartTimeUsMap(format, baseSpeedMultiplier);
+    this.speedsByStartTimeUs = buildSpeedByStartTimeUsMap(metadata, baseSpeedMultiplier);
   }
 
   @Override
@@ -67,8 +66,8 @@ import java.util.TreeMap;
   }
 
   private static ImmutableSortedMap<Long, Float> buildSpeedByStartTimeUsMap(
-      Format format, float baseSpeed) {
+      Metadata metadata, float baseSpeed) {
-    List<Segment> segments = extractSlowMotionSegments(format);
+    ImmutableList<Segment> segments = extractSlowMotionSegments(metadata);
 
     if (segments.isEmpty()) {
       return ImmutableSortedMap.of();
@@ -96,11 +95,7 @@ import java.util.TreeMap;
     return ImmutableSortedMap.copyOf(speedsByStartTimeUs);
   }
 
-  private static float getCaptureFrameRate(Format format) {
+  private static float getCaptureFrameRate(Metadata metadata) {
-    @Nullable Metadata metadata = format.metadata;
-    if (metadata == null) {
-      return C.RATE_UNSET;
-    }
     for (int i = 0; i < metadata.length(); i++) {
       Metadata.Entry entry = metadata.get(i);
       if (entry instanceof SmtaMetadataEntry) {
@@ -111,17 +106,14 @@ import java.util.TreeMap;
     return C.RATE_UNSET;
   }
 
-  private static ImmutableList<Segment> extractSlowMotionSegments(Format format) {
+  private static ImmutableList<Segment> extractSlowMotionSegments(Metadata metadata) {
     List<Segment> segments = new ArrayList<>();
-    @Nullable Metadata metadata = format.metadata;
-    if (metadata != null) {
     for (int i = 0; i < metadata.length(); i++) {
       Metadata.Entry entry = metadata.get(i);
       if (entry instanceof SlowMotionData) {
         segments.addAll(((SlowMotionData) entry).segments);
       }
     }
-    }
     return ImmutableList.sortedCopyOf(BY_START_THEN_END_THEN_DIVISOR, segments);
   }
 }

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

@@ -18,7 +18,6 @@ package androidx.media3.transformer;
 import static com.google.common.truth.Truth.assertThat;
 import static org.junit.Assert.assertThrows;
 
-import androidx.media3.common.Format;
 import androidx.media3.common.Metadata;
 import androidx.media3.common.util.Util;
 import androidx.media3.extractor.metadata.mp4.SlowMotionData;
@@ -39,9 +38,7 @@ public class SegmentSpeedProviderTest {
 
   @Test
   public void getSpeed_noSegments_returnsBaseSpeed() {
-    SegmentSpeedProvider provider =
+    SegmentSpeedProvider provider = new SegmentSpeedProvider(new Metadata(SMTA_SPEED_8));
-        new SegmentSpeedProvider(
-            new Format.Builder().setMetadata(new Metadata(SMTA_SPEED_8)).build());
     assertThat(provider.getSpeed(0)).isEqualTo(8);
     assertThat(provider.getSpeed(1_000_000)).isEqualTo(8);
   }
@@ -55,10 +52,7 @@ public class SegmentSpeedProviderTest {
             new Segment(/* startTimeMs= */ 2000, /* endTimeMs= */ 2500, /* speedDivisor= */ 2));
 
     SegmentSpeedProvider provider =
-        new SegmentSpeedProvider(
+        new SegmentSpeedProvider(new Metadata(new SlowMotionData(segments), SMTA_SPEED_8));
-            new Format.Builder()
-                .setMetadata(new Metadata(new SlowMotionData(segments), SMTA_SPEED_8))
-                .build());
 
     assertThat(provider.getSpeed(Util.msToUs(0))).isEqualTo(8);
     assertThat(provider.getSpeed(Util.msToUs(500))).isEqualTo(1);
@@ -77,9 +71,6 @@ public class SegmentSpeedProviderTest {
   public void getSpeed_withNegativeTimestamp_throwsException() {
     assertThrows(
         IllegalArgumentException.class,
-        () ->
+        () -> new SegmentSpeedProvider(new Metadata(SMTA_SPEED_8)).getSpeed(-1));
-            new SegmentSpeedProvider(
-                    new Format.Builder().setMetadata(new Metadata(SMTA_SPEED_8)).build())
-                .getSpeed(-1));
   }
 }