--- a/dom/media/mediasource/TrackBuffersManager.cpp
+++ b/dom/media/mediasource/TrackBuffersManager.cpp
@@ -2255,28 +2255,38 @@ TrackBuffersManager::FindCurrentPosition
     const RefPtr<MediaRawData>& sample = track[i];
     TimeInterval sampleInterval{
       TimeUnit::FromMicroseconds(sample->mTimecode),
       TimeUnit::FromMicroseconds(sample->mTimecode + sample->mDuration)};
 
     if (sampleInterval.ContainsStrict(trackData.mNextSampleTimecode)) {
       return i;
     }
+    if (sampleInterval.mStart > trackData.mNextSampleTimecode) {
+      // Samples are ordered by timecode. There's no need to search
+      // any further.
+      break;
+    }
   }
 
   for (uint32_t i = 0; i < track.Length(); i++) {
     const RefPtr<MediaRawData>& sample = track[i];
     TimeInterval sampleInterval{
       TimeUnit::FromMicroseconds(sample->mTimecode),
       TimeUnit::FromMicroseconds(sample->mTimecode + sample->mDuration),
       aFuzz};
 
     if (sampleInterval.ContainsWithStrictEnd(trackData.mNextSampleTimecode)) {
       return i;
     }
+    if (sampleInterval.mStart - aFuzz > trackData.mNextSampleTimecode) {
+      // Samples are ordered by timecode. There's no need to search
+      // any further.
+      break;
+    }
   }
 
   // We couldn't find our sample by decode timestamp. Attempt to find it using
   // presentation timestamp. There will likely be small jerkiness.
   for (uint32_t i = 0; i < track.Length(); i++) {
     const RefPtr<MediaRawData>& sample = track[i];
     TimeInterval sampleInterval{
       TimeUnit::FromMicroseconds(sample->mTime),