diff --git a/libraries/muxer/src/main/java/androidx/media3/muxer/Mp4Muxer.java b/libraries/muxer/src/main/java/androidx/media3/muxer/Mp4Muxer.java
index 4d7a654f83..a3fe966ce7 100644
--- a/libraries/muxer/src/main/java/androidx/media3/muxer/Mp4Muxer.java
+++ b/libraries/muxer/src/main/java/androidx/media3/muxer/Mp4Muxer.java
@@ -24,6 +24,7 @@ import androidx.annotation.IntDef;
 import androidx.annotation.Nullable;
 import androidx.media3.common.Format;
 import androidx.media3.common.Metadata;
+import androidx.media3.common.util.Log;
 import androidx.media3.common.util.UnstableApi;
 import androidx.media3.container.MdtaMetadataEntry;
 import androidx.media3.container.Mp4LocationData;
@@ -38,6 +39,7 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 import java.nio.ByteBuffer;
+import java.nio.channels.FileChannel;
 
 /**
  * A muxer for creating an MP4 container file.
@@ -176,6 +178,10 @@ public final class Mp4Muxer implements Muxer {
     }
   }
 
+  private static final String TAG = "Mp4Muxer";
+
+  private final FileOutputStream fileOutputStream;
+  private final FileChannel fileChannel;
   private final MetadataCollector metadataCollector;
   private final Mp4Writer mp4Writer;
 
@@ -185,12 +191,14 @@ public final class Mp4Muxer implements Muxer {
       AnnexBToAvccConverter annexBToAvccConverter,
       boolean sampleCopyEnabled,
       boolean attemptStreamableOutputEnabled) {
+    this.fileOutputStream = fileOutputStream;
+    this.fileChannel = fileOutputStream.getChannel();
     metadataCollector = new MetadataCollector();
     Mp4MoovStructure moovStructure =
         new Mp4MoovStructure(metadataCollector, lastFrameDurationBehavior);
     mp4Writer =
         new Mp4Writer(
-            fileOutputStream,
+            fileChannel,
             moovStructure,
             annexBToAvccConverter,
             sampleCopyEnabled,
@@ -288,10 +296,32 @@ public final class Mp4Muxer implements Muxer {
 
   @Override
   public void close() throws MuxerException {
+    @Nullable MuxerException exception = null;
     try {
-      mp4Writer.close();
+      mp4Writer.finishWritingSamples();
     } catch (IOException e) {
-      throw new MuxerException("Failed to close the muxer", e);
+      exception = new MuxerException("Failed to finish writing samples", e);
+    }
+    try {
+      fileChannel.close();
+    } catch (IOException e) {
+      if (exception == null) {
+        exception = new MuxerException("Failed to close output channel", e);
+      } else {
+        Log.e(TAG, "Failed to close output channel", e);
+      }
+    }
+    try {
+      fileOutputStream.close();
+    } catch (IOException e) {
+      if (exception == null) {
+        exception = new MuxerException("Failed to close output stream", e);
+      } else {
+        Log.e(TAG, "Failed to close output stream", e);
+      }
+    }
+    if (exception != null) {
+      throw exception;
     }
   }
 }
diff --git a/libraries/muxer/src/main/java/androidx/media3/muxer/Mp4Writer.java b/libraries/muxer/src/main/java/androidx/media3/muxer/Mp4Writer.java
index 15b20b6376..4b4b94f0f8 100644
--- a/libraries/muxer/src/main/java/androidx/media3/muxer/Mp4Writer.java
+++ b/libraries/muxer/src/main/java/androidx/media3/muxer/Mp4Writer.java
@@ -28,7 +28,6 @@ import androidx.media3.common.Format;
 import androidx.media3.common.util.Util;
 import androidx.media3.muxer.Muxer.TrackToken;
 import com.google.common.collect.Range;
-import java.io.FileOutputStream;
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.nio.channels.FileChannel;
@@ -43,7 +42,6 @@ import java.util.concurrent.atomic.AtomicBoolean;
   private static final int DEFAULT_MOOV_BOX_SIZE_BYTES = 400_000;
   private static final String FREE_BOX_TYPE = "free";
 
-  private final FileOutputStream outputStream;
   private final FileChannel output;
   private final Mp4MoovStructure moovGenerator;
   private final AnnexBToAvccConverter annexBToAvccConverter;
@@ -66,7 +64,8 @@ import java.util.concurrent.atomic.AtomicBoolean;
   /**
    * Creates an instance.
    *
-   * @param outputStream The {@link FileOutputStream} to write the data to.
+   * @param fileChannel The {@link FileChannel} to write the data to. The {@link FileChannel} can be
+   *     closed after {@link #finishWritingSamples() finishing writing samples}.
    * @param moovGenerator An {@link Mp4MoovStructure} instance to generate the moov box.
    * @param annexBToAvccConverter The {@link AnnexBToAvccConverter} to be used to convert H.264 and
    *     H.265 NAL units from the Annex-B format (using start codes to delineate NAL units) to the
@@ -75,13 +74,12 @@ import java.util.concurrent.atomic.AtomicBoolean;
    * @param attemptStreamableOutputEnabled Whether to attempt to write a streamable output.
    */
   public Mp4Writer(
-      FileOutputStream outputStream,
+      FileChannel fileChannel,
       Mp4MoovStructure moovGenerator,
       AnnexBToAvccConverter annexBToAvccConverter,
       boolean sampleCopyEnabled,
       boolean attemptStreamableOutputEnabled) {
-    this.outputStream = outputStream;
-    this.output = outputStream.getChannel();
+    this.output = fileChannel;
     this.moovGenerator = moovGenerator;
     this.annexBToAvccConverter = annexBToAvccConverter;
     this.sampleCopyEnabled = sampleCopyEnabled;
@@ -105,19 +103,19 @@ import java.util.concurrent.atomic.AtomicBoolean;
     doInterleave();
   }
 
-  public void close() throws IOException {
-    try {
-      for (int i = 0; i < tracks.size(); i++) {
-        flushPending(tracks.get(i));
-      }
+  /**
+   * Writes all the pending samples and the final moov box to the disk.
+   *
+   * <p>The output {@link FileChannel} can be closed after calling this method.
+   */
+  public void finishWritingSamples() throws IOException {
+    for (int i = 0; i < tracks.size(); i++) {
+      flushPending(tracks.get(i));
+    }
 
-      // Leave the file empty if no samples are written.
-      if (hasWrittenSamples.get()) {
-        writeMoovAndTrim();
-      }
-    } finally {
-      output.close();
-      outputStream.close();
+    // Leave the file empty if no samples are written.
+    if (hasWrittenSamples.get()) {
+      writeMoovAndTrim();
     }
   }