diff --git a/libraries/effect/src/main/java/androidx/media3/effect/DebugTraceUtil.java b/libraries/effect/src/main/java/androidx/media3/effect/DebugTraceUtil.java
index 08d6290fbe..7b31f045e0 100644
--- a/libraries/effect/src/main/java/androidx/media3/effect/DebugTraceUtil.java
+++ b/libraries/effect/src/main/java/androidx/media3/effect/DebugTraceUtil.java
@@ -60,6 +60,7 @@ public final class DebugTraceUtil {
   @Documented
   @Retention(RetentionPolicy.SOURCE)
   @StringDef({
+    EVENT_START,
     EVENT_INPUT_FORMAT,
     EVENT_OUTPUT_FORMAT,
     EVENT_ACCEPTED_INPUT,
@@ -83,6 +84,7 @@ public final class DebugTraceUtil {
   @Target(TYPE_USE)
   public @interface Event {}
 
+  public static final String EVENT_START = "Start";
   public static final String EVENT_INPUT_FORMAT = "InputFormat";
   public static final String EVENT_OUTPUT_FORMAT = "OutputFormat";
   public static final String EVENT_ACCEPTED_INPUT = "AcceptedInput";
@@ -107,6 +109,7 @@ public final class DebugTraceUtil {
   @Documented
   @Retention(RetentionPolicy.SOURCE)
   @StringDef({
+    COMPONENT_TRANSFORMER_INTERNAL,
     COMPONENT_ASSET_LOADER,
     COMPONENT_AUDIO_DECODER,
     COMPONENT_AUDIO_GRAPH,
@@ -124,6 +127,7 @@ public final class DebugTraceUtil {
   @Target(TYPE_USE)
   public @interface Component {}
 
+  public static final String COMPONENT_TRANSFORMER_INTERNAL = "TransformerInternal";
   public static final String COMPONENT_ASSET_LOADER = "AssetLoader";
   public static final String COMPONENT_AUDIO_DECODER = "AudioDecoder";
   public static final String COMPONENT_AUDIO_GRAPH = "AudioGraph";
@@ -141,6 +145,7 @@ public final class DebugTraceUtil {
   // For a given component, events are in the rough expected order that they occur.
   private static final ImmutableMap<@Component String, List<@Event String>> COMPONENTS_TO_EVENTS =
       ImmutableMap.<String, List<String>>builder()
+          .put(COMPONENT_TRANSFORMER_INTERNAL, ImmutableList.of(EVENT_START))
           .put(COMPONENT_ASSET_LOADER, ImmutableList.of(EVENT_INPUT_FORMAT, EVENT_OUTPUT_FORMAT))
           .put(
               COMPONENT_AUDIO_DECODER,
diff --git a/libraries/transformer/src/main/java/androidx/media3/transformer/TransformerInternal.java b/libraries/transformer/src/main/java/androidx/media3/transformer/TransformerInternal.java
index fdab8f04bd..253d7a057b 100644
--- a/libraries/transformer/src/main/java/androidx/media3/transformer/TransformerInternal.java
+++ b/libraries/transformer/src/main/java/androidx/media3/transformer/TransformerInternal.java
@@ -21,6 +21,8 @@ import static androidx.media3.common.C.TRACK_TYPE_VIDEO;
 import static androidx.media3.common.util.Assertions.checkArgument;
 import static androidx.media3.common.util.Assertions.checkState;
 import static androidx.media3.common.util.Util.contains;
+import static androidx.media3.effect.DebugTraceUtil.COMPONENT_TRANSFORMER_INTERNAL;
+import static androidx.media3.effect.DebugTraceUtil.EVENT_START;
 import static androidx.media3.transformer.AssetLoader.SUPPORTED_OUTPUT_TYPE_DECODED;
 import static androidx.media3.transformer.AssetLoader.SUPPORTED_OUTPUT_TYPE_ENCODED;
 import static androidx.media3.transformer.Composition.HDR_MODE_TONE_MAP_HDR_TO_SDR_USING_MEDIACODEC;
@@ -62,6 +64,7 @@ import androidx.media3.common.util.Clock;
 import androidx.media3.common.util.ConditionVariable;
 import androidx.media3.common.util.HandlerWrapper;
 import androidx.media3.common.util.Util;
+import androidx.media3.effect.DebugTraceUtil;
 import androidx.media3.muxer.Muxer.MuxerException;
 import androidx.media3.transformer.AssetLoader.CompositionSettings;
 import com.google.common.collect.ImmutableList;
@@ -272,6 +275,12 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
       progressState = Transformer.PROGRESS_STATE_WAITING_FOR_AVAILABILITY;
       progressValue = 0;
     }
+    DebugTraceUtil.logEvent(
+        COMPONENT_TRANSFORMER_INTERNAL,
+        EVENT_START,
+        /* presentationTimeUs= */ C.TIME_UNSET,
+        /* extraFormat= */ "%s",
+        /* extraArgs...= */ Util.DEVICE_DEBUG_INFO);
   }
 
   public @Transformer.ProgressState int getProgress(ProgressHolder progressHolder) {