E_ACCESSDENIED Error with Video File open with IMFSourceReader or IMFSourceResolver

I am trying to open video files using IMFSourceReader->MFCreateSourceReaderFromURL() orIMFSourceResolver->CreateObjectFromURL(). But both of them are returningE_ACCESSDENIED General Access denied error.

I am in windows 8.1 desktop and the video is in Pictures Library folder. I have the Capability for Pictures Library checked inPackage.appxmanifest page. But still I am getting access denied error.I am running the code in WinRT and I can open file using StorageFile->OpenAsync() to get the IRandomAccessStream. But Source Reader is not working.

any idea what is causing it and how I can get rid of this problem?