http://www.pcgamer.com/amds-crimson-relive-1791-driver-fixes-a-video-playback-issue-with-vega-cards/

AMD is getting ready to release a new Crimson ReLive driver (17.9.1), which may already be available by the time you read this. The GPU driver update does not deliver any specific game optimizations, as new drivers often do, and instead is focused on fixing a handful of issues Radeon graphics card owners have been having.

One of them applies specifically to Radeon RX Vega graphics cards. In some instances, resuming from sleep and then attempting to play back a video could cause a system to hang. This driver is supposed to fix that annoying issue.