diff --git a/libraries/muxer/src/main/java/androidx/media3/muxer/Boxes.java b/libraries/muxer/src/main/java/androidx/media3/muxer/Boxes.java
index 7bd9bcb26f..9c1829a838 100644
--- a/libraries/muxer/src/main/java/androidx/media3/muxer/Boxes.java
+++ b/libraries/muxer/src/main/java/androidx/media3/muxer/Boxes.java
@@ -56,7 +56,10 @@ import java.util.List;
   private static final int BYTES_PER_INTEGER = 4;
 
   // Box size (4 bytes) + Box name (4 bytes)
-  public static final int BOX_HEADER_SIZE = 2 * BYTES_PER_INTEGER;
+  public static final int BOX_HEADER_SIZE = 8;
+
+  // Box size = 1 to indicate 64-bit box size (4 bytes) + Box name (4 bytes) + actual size (8 bytes)
+  public static final int LARGE_SIZE_BOX_HEADER_SIZE = 16;
 
   public static final int MFHD_BOX_CONTENT_SIZE = 2 * BYTES_PER_INTEGER;
 
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 a280085a03..d06e131b96 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 static androidx.media3.container.Mp4Util.EDITABLE_TRACK_TYPE_DEPTH_INVERS
 import static androidx.media3.container.Mp4Util.EDITABLE_TRACK_TYPE_DEPTH_LINEAR;
 import static androidx.media3.container.Mp4Util.EDITABLE_TRACK_TYPE_DEPTH_METADATA;
 import static androidx.media3.container.Mp4Util.EDITABLE_TRACK_TYPE_SHARP;
+import static androidx.media3.muxer.Boxes.LARGE_SIZE_BOX_HEADER_SIZE;
 import static java.lang.annotation.ElementType.TYPE_USE;
 
 import android.media.MediaCodec.BufferInfo;
@@ -278,9 +279,6 @@ public final class Mp4Muxer implements Muxer {
 
   private static final String TAG = "Mp4Muxer";
 
-  // 4 bytes (indicating a 64-bit length field) + 4 byte (box type) + 8 bytes (actual length)
-  private static final int EDVD_BOX_HEADER_SIZE_BYTE = 16;
-
   private final FileOutputStream outputStream;
   private final FileChannel outputChannel;
   private final @LastFrameDurationBehavior int lastFrameDurationBehavior;
@@ -553,7 +551,7 @@ public final class Mp4Muxer implements Muxer {
             MdtaMetadataEntry.TYPE_INDICATOR_UNSIGNED_INT64);
     if (editableVideoMp4Writer != null) {
       long editableVideoDataSize = checkNotNull(cacheFileOutputStream).getChannel().size();
-      long edvdBoxSize = EDVD_BOX_HEADER_SIZE_BYTE + editableVideoDataSize;
+      long edvdBoxSize = LARGE_SIZE_BOX_HEADER_SIZE + editableVideoDataSize;
       metadataCollector.addMetadata(
           new MdtaMetadataEntry(
               MdtaMetadataEntry.KEY_EDITABLE_TRACKS_LENGTH,
@@ -584,11 +582,11 @@ public final class Mp4Muxer implements Muxer {
     }
     outputChannel.position(outputChannel.size());
     FileInputStream inputStream = new FileInputStream(checkNotNull(cacheFilePath));
-    ByteBuffer edvdBoxHeader = ByteBuffer.allocate(EDVD_BOX_HEADER_SIZE_BYTE);
+    ByteBuffer edvdBoxHeader = ByteBuffer.allocate(LARGE_SIZE_BOX_HEADER_SIZE);
     edvdBoxHeader.putInt(1); // indicating a 64-bit length field
     edvdBoxHeader.put(Util.getUtf8Bytes("edvd"));
     edvdBoxHeader.putLong(
-        EDVD_BOX_HEADER_SIZE_BYTE + inputStream.getChannel().size()); // the actual length
+        LARGE_SIZE_BOX_HEADER_SIZE + inputStream.getChannel().size()); // the actual length
     edvdBoxHeader.flip();
     outputChannel.write(edvdBoxHeader);
     ByteStreams.copy(inputStream, outputStream);
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 949ba92ffd..02f1864c8d 100644
--- a/libraries/muxer/src/main/java/androidx/media3/muxer/Mp4Writer.java
+++ b/libraries/muxer/src/main/java/androidx/media3/muxer/Mp4Writer.java
@@ -20,6 +20,7 @@ import static androidx.media3.common.util.Assertions.checkNotNull;
 import static androidx.media3.common.util.Assertions.checkState;
 import static androidx.media3.muxer.AnnexBUtils.doesSampleContainAnnexBNalUnits;
 import static androidx.media3.muxer.Boxes.BOX_HEADER_SIZE;
+import static androidx.media3.muxer.Boxes.LARGE_SIZE_BOX_HEADER_SIZE;
 import static java.lang.Math.max;
 import static java.lang.Math.min;
 
@@ -218,7 +219,7 @@ import java.util.concurrent.atomic.AtomicBoolean;
 
     // Start with an empty mdat box.
     mdatStart = outputFileChannel.position();
-    ByteBuffer header = ByteBuffer.allocate(4 + 4 + 8);
+    ByteBuffer header = ByteBuffer.allocate(LARGE_SIZE_BOX_HEADER_SIZE);
     header.putInt(1); // 4 bytes, indicating a 64-bit length field
     header.put(Util.getUtf8Bytes("mdat")); // 4 bytes
     header.putLong(16); // 8 bytes (the actual length)