4 ms·

I believe this is to some degree due to chroma key subsampling, where in a 4k stream you will only have 1080p worth of light intensity encoded (cluster of 4px).

I believe this is to some degree due to chroma key subsampling, where in a 4k stream you will only have 1080p worth of light intensity encoded (cluster of 4px). So if you play an 8k stream and downscale to 4k you actually have full chroma (1:1). There could of course be other factors involved as well but this is definitely a pretty big contributor.

olaulaja 3y ago
You have chroma and luma the wrong way around, chroma is color and luma is light intensity. Chroma is still the thing being subsampled. I've never really noticed effects from chroma subsampling so my guess would be the bitrate just being better with the higher resolution. Also "full res->compress->downsample" might be more efficient than "full res->downsample->compress" since downsampling is a (really bad) form of lossy compression as well.