--- a/dom/media/mediasource/TrackBuffersManager.cpp
+++ b/dom/media/mediasource/TrackBuffersManager.cpp
@@ -1393,21 +1393,16 @@ TrackBuffersManager::ProcessFrames(Track
     : TimeInterval(mAppendWindow.mStart, mAppendWindow.mEnd,
                    trackBuffer.mLongestFrameDuration.refOr(TimeUnit::FromMicroseconds(aSamples[0]->mDuration)));
 
   TimeIntervals samplesRange;
   uint32_t sizeNewSamples = 0;
   TrackBuffer samples; // array that will contain the frames to be added
                        // to our track buffer.
 
-  // We assume that no frames are contiguous within a media segment and as such
-  // don't need to check for discontinuity except for the first frame and should
-  // a frame be ignored due to the target window.
-  bool needDiscontinuityCheck = true;
-
   if (aSamples.Length()) {
     aTrackData.mLastParsedEndTime = TimeUnit();
   }
 
   for (auto& sample : aSamples) {
     SAMPLE_DEBUG("Processing %s frame(pts:%lld end:%lld, dts:%lld, duration:%lld, "
                "kf:%d)",
                aTrackData.mInfo->mMimeType.get(),
@@ -1458,17 +1453,17 @@ TrackBuffersManager::ProcessFrames(Track
       mSourceBufferAttributes->mGenerateTimestamps
         ? mSourceBufferAttributes->GetTimestampOffset()
         : TimeUnit::FromMicroseconds(sample->mTimecode) + mSourceBufferAttributes->GetTimestampOffset();
 
     // 6. If last decode timestamp for track buffer is set and decode timestamp is less than last decode timestamp:
     // OR
     // If last decode timestamp for track buffer is set and the difference between decode timestamp and last decode timestamp is greater than 2 times last frame duration:
 
-    if (needDiscontinuityCheck && trackBuffer.mLastDecodeTimestamp.isSome() &&
+    if (trackBuffer.mLastDecodeTimestamp.isSome() &&
         (decodeTimestamp < trackBuffer.mLastDecodeTimestamp.ref() ||
          decodeTimestamp - trackBuffer.mLastDecodeTimestamp.ref() > 2*trackBuffer.mLongestFrameDuration.ref())) {
       MSE_DEBUG("Discontinuity detected.");
       SourceBufferAppendMode appendMode = mSourceBufferAttributes->GetAppendMode();
 
       // 1a. If mode equals "segments":
       if (appendMode == SourceBufferAppendMode::Segments) {
         // Set group end timestamp to presentation timestamp.
@@ -1508,17 +1503,16 @@ TrackBuffersManager::ProcessFrames(Track
             : TimeInterval(TimeUnit::FromMicroseconds(sample->mTime) + mSourceBufferAttributes->GetTimestampOffset(),
                            TimeUnit::FromMicroseconds(sample->GetEndTime()) + mSourceBufferAttributes->GetTimestampOffset());
         decodeTimestamp =
           mSourceBufferAttributes->mGenerateTimestamps
             ? mSourceBufferAttributes->GetTimestampOffset()
             : TimeUnit::FromMicroseconds(sample->mTimecode) + mSourceBufferAttributes->GetTimestampOffset();
       }
       trackBuffer.mNeedRandomAccessPoint = false;
-      needDiscontinuityCheck = false;
     }
 
     // 7. Let frame end timestamp equal the sum of presentation timestamp and frame duration.
     // This is sampleInterval.mEnd
 
     // 8. If presentation timestamp is less than appendWindowStart, then set the need random access point flag to true, drop the coded frame, and jump to the top of the loop to start processing the next coded frame.
     // 9. If frame end timestamp is greater than appendWindowEnd, then set the need random access point flag to true, drop the coded frame, and jump to the top of the loop to start processing the next coded frame.
     if (!targetWindow.ContainsWithStrictEnd(sampleInterval)) {
@@ -1527,17 +1521,16 @@ TrackBuffersManager::ProcessFrames(Track
         // Insert the samples processed so far.
         InsertFrames(samples, samplesRange, trackBuffer);
         samples.Clear();
         samplesRange = TimeIntervals();
         trackBuffer.mSizeBuffer += sizeNewSamples;
         sizeNewSamples = 0;
       }
       trackBuffer.mNeedRandomAccessPoint = true;
-      needDiscontinuityCheck = true;
       continue;
     }
 
     samplesRange += sampleInterval;
     sizeNewSamples += sample->ComputedSizeOfIncludingThis();
     sample->mTime = sampleInterval.mStart.ToMicroseconds();
     sample->mTimecode = decodeTimestamp.ToMicroseconds();
     sample->mTrackInfo = trackBuffer.mLastInfo;