Converting 4k HDR to 1080 HDR

[strudo76]

Hi there

I have a couple of questions.

I have an EPSON TW9400 projector (Epson Pro Cinema 6050UB in USA), which is a non 4K projector but does the pixel shifting upscaling. I'm interested in opinions regarding whether it's worth using 4K source material, or if it's just wasting my time. To me, it would seem a waste as the machine would have to downscale to 1080 as that's what the hardware can process, but others have told me a 4K source will still provide a better experience in the end. Any thoughts on this would be appreciated.

Related to that, if I was to take a HDR source, which is usually a 4K video, and use ffmpeg to downscale to 1080 but keep the HDR information using the hdr-opt parameters, will that make a HDR compliant video, or are the HDR parameters specific to the resolution?

Thanks for reading.

[usually_quiet]

Your projector accepts 2160p HDR10 input via HDMI. If you have a playback device with HDMI 2.0 out or HDMI 2.1 out that can decode 2160p HDR10 video and pass through the HDR10 metadata, use 2160p HDR10 video when you have it available. Re-encoding 2160p files to 1080p just makes more work and doesn't improve quality.

[strudo76]

Sounds like good advice. Thanks.