Mesa commit 

commit 51227b41c6b026f5b0a3925093b91800cdfcc923
Author: Indrajit Das <indrajit-kumar.das@amd.com>
Date:   Fri May 27 18:27:15 2016 +0530

    radeon/uvd: fix overflow error while calculating bit stream buffer size

gets rid of the errors and so mpv/mplayer will attempt to use uvd, but no video
is displayed, just a black screen.