diff --git a/libraries/transformer/src/androidTest/java/androidx/media3/transformer/AndroidTestUtil.java b/libraries/transformer/src/androidTest/java/androidx/media3/transformer/AndroidTestUtil.java
index 17786b98ef..795632a139 100644
--- a/libraries/transformer/src/androidTest/java/androidx/media3/transformer/AndroidTestUtil.java
+++ b/libraries/transformer/src/androidTest/java/androidx/media3/transformer/AndroidTestUtil.java
@@ -57,6 +57,7 @@ import androidx.media3.effect.GlShaderProgram;
 import androidx.media3.effect.PassthroughShaderProgram;
 import androidx.media3.effect.ScaleAndRotateTransformation;
 import androidx.media3.exoplayer.mediacodec.MediaCodecUtil;
+import androidx.media3.muxer.Muxer;
 import androidx.media3.test.utils.BitmapPixelTestUtil;
 import androidx.media3.test.utils.VideoDecodingWrapper;
 import com.google.common.base.Ascii;
@@ -1200,6 +1201,12 @@ public final class AndroidTestUtil {
     throw new AssumptionViolatedException(skipReason);
   }
 
+  /** Returns a {@link Muxer.Factory} depending upon the API level. */
+  public static Muxer.Factory getMuxerFactoryBasedOnApi() {
+    // MediaMuxer supports B-frame from API > 24.
+    return SDK_INT > 24 ? new DefaultMuxer.Factory() : new InAppMuxer.Factory.Builder().build();
+  }
+
   private static boolean canDecode(Format format) {
     if (MimeTypes.isImage(format.sampleMimeType)) {
       return Util.isBitmapFactorySupportedMimeType(format.sampleMimeType);
diff --git a/libraries/transformer/src/androidTest/java/androidx/media3/transformer/ParameterizedItemExportAndroidTest.java b/libraries/transformer/src/androidTest/java/androidx/media3/transformer/ParameterizedItemExportAndroidTest.java
index 72686867cc..fb69f1f1c9 100644
--- a/libraries/transformer/src/androidTest/java/androidx/media3/transformer/ParameterizedItemExportAndroidTest.java
+++ b/libraries/transformer/src/androidTest/java/androidx/media3/transformer/ParameterizedItemExportAndroidTest.java
@@ -21,6 +21,7 @@ import static androidx.media3.transformer.AndroidTestUtil.JPG_ASSET;
 import static androidx.media3.transformer.AndroidTestUtil.MP4_ASSET;
 import static androidx.media3.transformer.AndroidTestUtil.PNG_ASSET;
 import static androidx.media3.transformer.AndroidTestUtil.assumeFormatsSupported;
+import static androidx.media3.transformer.AndroidTestUtil.getMuxerFactoryBasedOnApi;
 import static com.google.common.truth.Truth.assertThat;
 
 import android.content.Context;
@@ -120,6 +121,7 @@ public final class ParameterizedItemExportAndroidTest {
     assumeFormatsSupported(context, testId, itemConfig.format, itemConfig.outputFormat);
     Transformer transformer =
         new Transformer.Builder(context)
+            .setMuxerFactory(getMuxerFactoryBasedOnApi())
             .setEncoderFactory(
                 new DefaultEncoderFactory.Builder(context).setEnableFallback(false).build())
             .build();
diff --git a/libraries/transformer/src/androidTest/java/androidx/media3/transformer/TransformerEndToEndTest.java b/libraries/transformer/src/androidTest/java/androidx/media3/transformer/TransformerEndToEndTest.java
index 27a34ced98..195f830817 100644
--- a/libraries/transformer/src/androidTest/java/androidx/media3/transformer/TransformerEndToEndTest.java
+++ b/libraries/transformer/src/androidTest/java/androidx/media3/transformer/TransformerEndToEndTest.java
@@ -33,6 +33,7 @@ import static androidx.media3.transformer.AndroidTestUtil.assumeFormatsSupported
 import static androidx.media3.transformer.AndroidTestUtil.createFrameCountingEffect;
 import static androidx.media3.transformer.AndroidTestUtil.createOpenGlObjects;
 import static androidx.media3.transformer.AndroidTestUtil.generateTextureFromBitmap;
+import static androidx.media3.transformer.AndroidTestUtil.getMuxerFactoryBasedOnApi;
 import static androidx.media3.transformer.AndroidTestUtil.recordTestSkipped;
 import static androidx.media3.transformer.ExportResult.CONVERSION_PROCESS_NA;
 import static androidx.media3.transformer.ExportResult.CONVERSION_PROCESS_TRANSCODED;
@@ -679,7 +680,10 @@ public class TransformerEndToEndTest {
         /* outputFormat= */ MP4_ASSET_PHOTOS_TRIM_OPTIMIZATION_VIDEO.videoFormat);
 
     Transformer transformer =
-        new Transformer.Builder(context).experimentalSetTrimOptimizationEnabled(true).build();
+        new Transformer.Builder(context)
+            .experimentalSetTrimOptimizationEnabled(true)
+            .setMuxerFactory(getMuxerFactoryBasedOnApi())
+            .build();
 
     // The previous sample is at 1137 and the next sample (which is a sync sample) is at 1171.
     long clippingStartMs = 1138;