--- a/dom/media/MediaCache.cpp
+++ b/dom/media/MediaCache.cpp
@@ -2911,16 +2911,20 @@ MediaCacheStream::InitAsCloneInternal(Me
   mResourceID = aOriginal->mResourceID;
 
   // Grab cache blocks from aOriginal as readahead blocks for our stream
   mStreamLength = aOriginal->mStreamLength;
   mIsTransportSeekable = aOriginal->mIsTransportSeekable;
   mDownloadStatistics = aOriginal->mDownloadStatistics;
   mDownloadStatistics.Stop();
 
+  // Notify the client that we have new data so the decoder has a chance to
+  // compute 'canplaythrough' and buffer ranges.
+  mClient->CacheClientNotifyDataReceived();
+
   if (aOriginal->mDidNotifyDataEnded &&
       NS_SUCCEEDED(aOriginal->mNotifyDataEndedStatus)) {
     mNotifyDataEndedStatus = aOriginal->mNotifyDataEndedStatus;
     mDidNotifyDataEnded = true;
     mClient->CacheClientNotifyDataEnded(mNotifyDataEndedStatus);
   }
 
   for (uint32_t i = 0; i < aOriginal->mBlocks.Length(); ++i) {