diff --git a/packager/media/formats/mp4/mp4_media_parser.cc b/packager/media/formats/mp4/mp4_media_parser.cc
index 4a02112578..98de99bfa6 100644
--- a/packager/media/formats/mp4/mp4_media_parser.cc
+++ b/packager/media/formats/mp4/mp4_media_parser.cc
@@ -410,9 +410,12 @@ bool MP4MediaParser::ParseMoov(BoxReader* reader) {
 
     // Calculate duration (based on timescale).
     int64_t duration = 0;
-    if (track->media.header.duration > 0) {
+    if (track->media.header.duration > 0 &&
+        track->media.header.duration != std::numeric_limits<uint64_t>::max()) {
       duration = track->media.header.duration;
-    } else if (moov_->extends.header.fragment_duration > 0) {
+    } else if (moov_->extends.header.fragment_duration > 0 &&
+               moov_->extends.header.fragment_duration !=
+                   std::numeric_limits<uint64_t>::max()) {
       DCHECK(moov_->header.timescale != 0);
       duration = Rescale(moov_->extends.header.fragment_duration,
                          moov_->header.timescale, timescale);
diff --git a/packager/media/formats/mp4/mp4_muxer.cc b/packager/media/formats/mp4/mp4_muxer.cc
index c7425b8b44..64f0465780 100644
--- a/packager/media/formats/mp4/mp4_muxer.cc
+++ b/packager/media/formats/mp4/mp4_muxer.cc
@@ -248,7 +248,9 @@ Status MP4Muxer::DelayInitializeMuxer() {
       ftyp->compatible_brands.push_back(FOURCC_cmfc);
 
     // Carry over movie extends header duration from init segment.
-    moov->extends.header.fragment_duration = streams()[0].get()->duration();
+    if (streams()[0].get()->duration() > 0) {
+      moov->extends.header.fragment_duration = streams()[0].get()->duration();
+    }
   }
 
   moov->header.creation_time = IsoTimeNow();