diff --git a/packager/media/formats/webm/segmenter.cc b/packager/media/formats/webm/segmenter.cc
index e9efa6bc98..b3ffdcfb18 100644
--- a/packager/media/formats/webm/segmenter.cc
+++ b/packager/media/formats/webm/segmenter.cc
@@ -150,9 +150,11 @@ Status Segmenter::Initialize(const StreamInfo& info,
 }
 
 Status Segmenter::Finalize() {
-  uint64_t duration =
-      prev_sample_->pts() - first_timestamp_ + prev_sample_->duration();
-  segment_info_.set_duration(FromBmffTimestamp(duration));
+  if (prev_sample_) {
+    uint64_t duration =
+        prev_sample_->pts() - first_timestamp_ + prev_sample_->duration();
+    segment_info_.set_duration(FromBmffTimestamp(duration));
+  }
   return DoFinalize();
 }