Just leaving this here for potential importers of the Hong Kong (Snapdragon 855) variant of this phone. This is a problem I've run into recently which I've barely seen any mention of. WARNING: Lengthy post ahead.
For owners of the SM-G9750 (S10+ CN / HK model), I'm trying to get some verification here on a possible software issue. I'm trying to play a 4K video file locally (specifically a 4K HDR H.265 / HEVC MKV @ 24fps video, but I believe this bug may apply to all UHD video playback - I'm not sure as I haven't done enough testing) and it seems to be dropping frames and stuttering throughout. I cannot get it to play smoothly despite trying all of the following:
Setting the phone to Performance mode.
Trying different players - in this case, the default video player, MX Player Pro and VLC.
Moving the video player app to Game Launcher and optimizing them for performance.
Forced 2D GPU Rendering in Developer Options.
Changing display resolution from WQHD to FHD.
Moving the video file from SD card to internal storage.
Disabling / uninstalling all apps which use Accessibility Services.
None of these worked. ---UNTIL--- I tried using the screen recorder, from the Game Launcher settings, whilst watching the video. Playback was then perfect! No dropped frames, completely smooth, like it should be. The other alternative was to use software decoding but then colours would appear muted and battery life takes a huge hit.
So what's the deal here? Is the CPU or GPU not kicking in / being throttled whenever I launch a video player app? I'm assuming this is the case as the screen recorder seems to boost playback performance once I activate it. I'm on the June update and I'm not sure if this bug was introduced recently (I never tested 4K playback until now).
Owners of this particular model, could you please confirm if you are having this issue? Try watching a 4K video with lots of action and camera panning movements - that's where you can detect dropped frames or stuttering easily. I could provide the file I'm using for reference but it's a clip from a movie and I'm not sure if I'm allowed to share it here.