diff --git a/RELEASENOTES.md b/RELEASENOTES.md
index 271641431b8..e7b383bc6ab 100644
--- a/RELEASENOTES.md
+++ b/RELEASENOTES.md
@@ -5,6 +5,9 @@
 *   Common Library:
 *   ExoPlayer:
 *   Transformer:
+*   Extractors:
+    *   Fix media duration parsing in `mdhd` box of MP4 files to handle `-1`
+        values ([#1819](https://github.com/androidx/media/issues/1819)).
 *   DataSource:
     *   `DataSourceContractTest`: Assert that `DataSource.getUri()` returns the
         resolved URI (as documented). Where this is different to the requested
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 9b51d089d5b..8bc285fc2cc 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
@@ -958,14 +958,28 @@ private static MdhdData parseMdhd(ParsableByteArray mdhd) {
     int version = parseFullBoxVersion(fullAtom);
     mdhd.skipBytes(version == 0 ? 8 : 16);
     long timescale = mdhd.readUnsignedInt();
-    long mediaDuration = version == 0 ? mdhd.readUnsignedInt() : mdhd.readUnsignedLongToLong();
+    boolean mediaDurationUnknown = true;
+    int mediaDurationPosition = mdhd.getPosition();
+    int mediaDurationByteCount = version == 0 ? 4 : 8;
+    for (int i = 0; i < mediaDurationByteCount; i++) {
+      if (mdhd.getData()[mediaDurationPosition + i] != -1) {
+        mediaDurationUnknown = false;
+        break;
+      }
+    }
     long mediaDurationUs;
-    if (mediaDuration == 0) {
-      // 0 duration normally indicates that the file is fully fragmented (i.e. all of the media
-      // samples are in fragments). Treat as unknown.
+    if (mediaDurationUnknown) {
+      mdhd.skipBytes(mediaDurationByteCount);
       mediaDurationUs = C.TIME_UNSET;
     } else {
-      mediaDurationUs = Util.scaleLargeTimestamp(mediaDuration, C.MICROS_PER_SECOND, timescale);
+      long mediaDuration = version == 0 ? mdhd.readUnsignedInt() : mdhd.readUnsignedLongToLong();
+      if (mediaDuration == 0) {
+        // 0 duration normally indicates that the file is fully fragmented (i.e. all of the media
+        // samples are in fragments). Treat as unknown.
+        mediaDurationUs = C.TIME_UNSET;
+      } else {
+        mediaDurationUs = Util.scaleLargeTimestamp(mediaDuration, C.MICROS_PER_SECOND, timescale);
+      }
     }
     int languageCode = mdhd.readUnsignedShort();
     String language =