With media-video/ffmpeg-3.2.4, any attempt to play a video or a stream with ffplay fails, with the error
SDL: could not set video mode - exiting
With media-video/ffmpeg-2.8.10, ffplay works as expected.
Does it work with the other versions?
ffplay from ffmpeg-3.3.2 (~amd64) does start and does not show that error, although it seems to be unable to play HLS streams as smoothly as ffmpeg-2.*.