copy timestamp & metadata in VideoFrame.clone(). reserve necessary size
add Frame.swap(). check planeCount
fix fps computation
players: set opengl backend in command line or app name
fix wrong plane size check
dxva: enable hevc. must use lavfilters' ffmpeg now
example: simpleplayer add simple ui
videooutput always check whether it renderer is available
player: fix text in head of windows
Merge remote-tracking branch 'upstream/master'