A minor thing I noticed today… Playing a 4K HDR 60fps file (the HEVC version of “The World in HDR”) there are not one but two HDMI mode switches before the video starts playing: the first switch is from the desktop resolution to 2160p/59.94Hz/SDR (the screen goes black, then the picture comes back up); then there’s a slight pause; then there’s a second mode switch to 2160p/59.94Hz/HDR (which makes the screen go black again); and then finally the video comes up.
I would have thought it ought to switch directly to 2160p/59.94Hz/HDR in a single transition…?
I think it’s connected to the “Delay after change of refresh rate” setting in Settings / System / Display. If I make that setting longer (15 seconds, say) then the first mode switch happens immediately, and I eventually get back to the UI; the second mode switch happens 15 seconds after I first tell the video to play, right at the moment it actually starts playing.
It seems to be affecting all of my HDR test clips at the moment.
Just to recap, when I start playing (say) a 4K HDR 24fps video, there are two separate mode switches: there’s an immediate change to 4K 24Hz SDR, then there’s the delay associated with the “Delay after change of refresh rate” setting in Settings / System / Display, then there’s a second switch from SDR to HDR at the moment the video actually starts playing. This means that the delay setting isn’t quite working the way it should, because the screen is still going black after playback starts, no matter how long the delay setting is.