PINE64

Full Version: is 4K Really 4K?
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I'm using ayufan's latest image with the ROCK64 connected to a 4K display and the display says the input is 4K resolution. 
image: android-7.1-rock-64-rock64_atv-v0.3.4-r86-raw_sd2emmc.img.xz

However if you issue the command 
     "adb shell dumpsys SurfaceFlinger"

The framebuffer is 1920x1080.  When playing a 4K video using VLC (or any other player) you will see the video is 4K, but is scaled to the framebuffer 1920x1080 and then the HDMI display logic would scale it back to 3840x2160.   When issuing the same commands on a NVIDIA shield the framebuffer is 3840x2160, so no down and up scaling occurs. 

Admittedly behind the scenes the scaling might not be happening.  Does anyone know if this is the case?

Steve
(06-19-2018, 01:55 PM)sbakke Wrote: [ -> ]I'm using ayufan's latest image with the ROCK64 connected to a 4K display and the display says the input is 4K resolution. 
image: android-7.1-rock-64-rock64_atv-v0.3.4-r86-raw_sd2emmc.img.xz

However if you issue the command 
     "adb shell dumpsys SurfaceFlinger"

The framebuffer is 1920x1080.  When playing a 4K video using VLC (or any other player) you will see the video is 4K, but is scaled to the framebuffer 1920x1080 and then the HDMI display logic would scale it back to 3840x2160.   When issuing the same commands on a NVIDIA shield the framebuffer is 3840x2160, so no down and up scaling occurs. 

Admittedly behind the scenes the scaling might not be happening.  Does anyone know if this is the case?

Steve

Yes, everything is downscaled to 1080p.
The only app not downscaling is Kodi 18 if you enable auto frame-rate switching.
But the Rock64 only supports 4K@25hz or 4K@30hz in Kodi 18 not 4K@50hz or 4K@60hz or HDR like the Shield.
Only LibreELEC supports 4K@50hz or 4K@60hz.
VLC will play everything at 1080p at the wrong frame-rate too.

The Shield is the only Android device that has both a 4K framebuffer and 4K resolution.