Recently I needed to check if Picture on a slide is actually embedded video, so I implemented method isSetVideoFile() of XSLFPictureShape instance. Also added method for getting Link attribute to video.
Created attachment 38083 [details] Patch with a test presentation file
Thanks - I added r1894860 - I renamed your methods a little - if you feel strongly about the method comments, please get back to us
Setting to resolved as the core change is done now, please reopen if there is still something missing.