Bug 945645 - Only init WMF video decoding if we have a video container. r=padenot.

content/media/wmf/WMFReader.cpp

@@ -105,6 +105,7 @@ WMFReader::InitializeDXVA()
   if (!Preferences::GetBool("media.windows-media-foundation.use-dxva", false)) {
     return false;
   }
+  MOZ_ASSERT(mDecoder->GetImageContainer());
 
   // Extract the layer manager backend type so that we can determine
   // whether it's worthwhile using DXVA. If we're not running with a D3D
@@ -151,7 +152,8 @@ WMFReader::Init(MediaDecoderReader* aCloneDonor)
   rv = mByteStream->Init();
   NS_ENSURE_SUCCESS(rv, rv);
 
-  if (IsVideoContentType(mDecoder->GetResource()->GetContentType())) {
+  if (mDecoder->GetImageContainer() != nullptr &&
+      IsVideoContentType(mDecoder->GetResource()->GetContentType())) {
     mUseHwAccel = InitializeDXVA();
   } else {
     mUseHwAccel = false;
@@ -345,6 +347,11 @@ WMFReader::ConfigureVideoDecoder()
     return S_OK;
   }
 
+  if (!mDecoder->GetImageContainer()) {
+    // We can't display the video, so don't bother to decode; disable the stream.
+    return mSourceReader->SetStreamSelection(MF_SOURCE_READER_FIRST_VIDEO_STREAM, FALSE);
+  }
+
   static const GUID MP4VideoTypes[] = {
     MFVideoFormat_H264
   };