diff --git a/RELEASENOTES.md b/RELEASENOTES.md
index e7b383bc6a..8363c5fc08 100644
--- a/RELEASENOTES.md
+++ b/RELEASENOTES.md
@@ -8,6 +8,8 @@
 *   Extractors:
     *   Fix media duration parsing in `mdhd` box of MP4 files to handle `-1`
         values ([#1819](https://github.com/androidx/media/issues/1819)).
+    *   Add support for identifying `h263` box in MP4 files for H.263 video
+        ([#1821](https://github.com/androidx/media/issues/1821)).
 *   DataSource:
     *   `DataSourceContractTest`: Assert that `DataSource.getUri()` returns the
         resolved URI (as documented). Where this is different to the requested
diff --git a/libraries/container/src/main/java/androidx/media3/container/Mp4Box.java b/libraries/container/src/main/java/androidx/media3/container/Mp4Box.java
index a410436205..bdf4709096 100644
--- a/libraries/container/src/main/java/androidx/media3/container/Mp4Box.java
+++ b/libraries/container/src/main/java/androidx/media3/container/Mp4Box.java
@@ -116,6 +116,9 @@ public abstract class Mp4Box {
 
   public static final int TYPE_H263 = 0x48323633;
 
+  @SuppressWarnings("ConstantCaseForConstants")
+  public static final int TYPE_h263 = 0x68323633;
+
   @SuppressWarnings("ConstantCaseForConstants")
   public static final int TYPE_d263 = 0x64323633;
 
diff --git a/libraries/extractor/src/main/java/androidx/media3/extractor/mp4/BoxParser.java b/libraries/extractor/src/main/java/androidx/media3/extractor/mp4/BoxParser.java
index 8bc285fc2c..c4dc05e567 100644
--- a/libraries/extractor/src/main/java/androidx/media3/extractor/mp4/BoxParser.java
+++ b/libraries/extractor/src/main/java/androidx/media3/extractor/mp4/BoxParser.java
@@ -1026,6 +1026,7 @@ public final class BoxParser {
           || childAtomType == Mp4Box.TYPE_hev1
           || childAtomType == Mp4Box.TYPE_s263
           || childAtomType == Mp4Box.TYPE_H263
+          || childAtomType == Mp4Box.TYPE_h263
           || childAtomType == Mp4Box.TYPE_vp08
           || childAtomType == Mp4Box.TYPE_vp09
           || childAtomType == Mp4Box.TYPE_av01