--- a/dom/media/AccurateSeekTask.cpp
+++ b/dom/media/AccurateSeekTask.cpp
@@ -90,17 +90,22 @@ AccurateSeekTask::CalculateNewCurrentTim
   // the real decoded samples' start time.
   if (mTarget.IsAccurate()) {
     return seekTime;
   }
 
   // For the fast seek, we update the newCurrentTime with the decoded audio and
   // video samples, set it to be the one which is closet to the seekTime.
   if (mTarget.IsFast()) {
-    MOZ_ASSERT(mSeekedAudioData || mSeekedVideoData);
+
+    // A situation that both audio and video approaches the end.
+    if (!mSeekedAudioData && !mSeekedVideoData) {
+      return seekTime;
+    }
+
     const int64_t audioStart = mSeekedAudioData ? mSeekedAudioData->mTime : INT64_MAX;
     const int64_t videoStart = mSeekedVideoData ? mSeekedVideoData->mTime : INT64_MAX;
     const int64_t audioGap = std::abs(audioStart - seekTime);
     const int64_t videoGap = std::abs(videoStart - seekTime);
     return audioGap <= videoGap ? audioStart : videoStart;
   }
 
   MOZ_ASSERT(false, "AccurateSeekTask doesn't handle other seek types.");