Flickering when playing upscaled/downscaled (1080P24 -> 4K24 -> 1080P24) video

My main viewing device is a 60" Pioneer Kuro TV, which does 1080P max. Recently i’ve added a JVC-X7500 4K projector. I use an Apple TV4 with Infuse and a Dune 4K player as sources. Now, for ‘regular’ watching and mostly during daytime, i will use the Kuro TV, for movies, and in the evening and at night, the projector screen is lowered in front of the Kuro and i watch stuff on the 120" screen using the JVC.

This means that IF i want to watch in daytime on the TV, i have to somehow downscale 4K material to 1080P, otherwise i can’t watch it on the telly. Or i need to change the output resolution of the Apple TV to 1080P, and change it back to 4K when i want to watch material on the JVC projector…

What i ended up with was an HDFury Vertex. This device has 2 HDMI inputs and 2 HDMI outputs, from which one can be used to scale down to 1080P. My Kuro is on the downscale HDMI port, the JVC on the ‘normal’ port… that way i can leave the Apple TV in 4K resolution, and play anything i want. I also use the Vertex to strip HDR metadata and have the JVC projector select a custom HDR mode etc). So far so good.

But… i noticed that if i have the Apple TV’s output resolution set to 4K, and i play a 1080P24 MKV file, the image on the Kuro TV has some sort of faint brightness flickering in the image. In this case, the Apple TV basically upscales the 1080P24 MKV to 4K24, outputs it to the Vertex, and the Vertex downscales it back to 1080P24 and sends it to the TV… a lot of unneccesary down/up/downscaling, i know.

If i set the Apple TV’s resolution to 1080P24 (or 1080P60…), so there is no upscaling by the ATV and downscaling by the Vertex, the flickering is gone. Also, on the JVC there is no flickering (the JVC will display the original 4K24 or 1080P without processing, from the ATV) Now, you would suspect that the flickering may be caused by the Vertex, but i don’t think that is the case. If i replace the Apple TV with my Dune 4K player, and configure the same scenario, so Dune is set to 4K24, is playing a 1080P24 file which it will upscale to 4K24, send it to the Vertex, which downscales it back to 1080P24, the resulting video is perfect… no flickering at all.

This makes me think this is either Apple TV or Infuse related. I hope i explained it clearly :slight_smile: Offcourse the workaround in this case is to manually set the AppleTV’s resolution to 1080P if i’m watching it on the TV, and back to 4K if i watch it on the projector… but it would be nice if i could just leave the ATV in 4K and watch anything anywhere all the time :slight_smile: