--- a/dom/media/omx/MediaOmxReader.cpp
+++ b/dom/media/omx/MediaOmxReader.cpp
@@ -384,19 +384,18 @@ bool MediaOmxReader::DecodeVideoFrame(bo
       // and we will preserve the ratio of the crop rectangle as it
       // was reported relative to the picture size reported by the container.
       picture.x = (mPicture.x * frame.Y.mWidth) / mInitialFrame.width;
       picture.y = (mPicture.y * frame.Y.mHeight) / mInitialFrame.height;
       picture.width = (frame.Y.mWidth * mPicture.width) / mInitialFrame.width;
       picture.height = (frame.Y.mHeight * mPicture.height) / mInitialFrame.height;
     }
 
-    MOZ_ASSERT(mStreamSource);
     // This is the approximate byte position in the stream.
-    int64_t pos = mStreamSource->Tell();
+    int64_t pos = mStreamSource ? mStreamSource->Tell() : 0;
 
     nsRefPtr<VideoData> v;
     if (!frame.mGraphicBuffer) {
 
       VideoData::YCbCrBuffer b;
       b.mPlanes[0].mData = static_cast<uint8_t *>(frame.Y.mData);
       b.mPlanes[0].mStride = frame.Y.mStride;
       b.mPlanes[0].mHeight = frame.Y.mHeight;
@@ -487,19 +486,18 @@ void MediaOmxReader::NotifyDataArrivedIn
   }
 }
 
 bool MediaOmxReader::DecodeAudioData()
 {
   MOZ_ASSERT(OnTaskQueue());
   EnsureActive();
 
-  MOZ_ASSERT(mStreamSource);
   // This is the approximate byte position in the stream.
-  int64_t pos = mStreamSource->Tell();
+  int64_t pos = mStreamSource ? mStreamSource->Tell() : 0;
 
   // Read next frame
   MPAPI::AudioFrame source;
   if (!mOmxDecoder->ReadAudio(&source, mAudioSeekTimeUs)) {
     return false;
   }
   mAudioSeekTimeUs = -1;