Comment # 29 on bug 1139791 from Stakanov Schufter

So, there has been apparently no change in the situation. 
va-api with vlc works for vlc, but kaffeine and vidcutter seem to default to
vdpau? Even when setting vlc to use va-api, kaffeine does not honor this and
crashes. Vidcutter gives only green clutter instead of images for cutting. 
If you have any clue how to force kaffeine to use va-api as a work around then
I wold be thankful and try it.