Strange color artifacts in rendered video

Question

I'm seeing strange color artifacts and blurriness in a CGI video exported by Premiere Pro 25.6.3 under Windows 11, export format H264 (see short video clip below). The scene features a gradual lighting change that goesfrom green to red while the camera is in motion. However, when rendered the video's colors appear blotchy and steppy with intermittent blurriness overall.

I've examined the individual CGI frames and they show no such artifacts, as well as when previewing the video in Premiere. Any suggestions? Thanks.

https://vimeo.com/1146661155/708d6171e8?fl=pl&fe=cm

Averdahl · Accepted Answer

Yes, that looks great! &#128578; I think I've resolved the issue by exporting the video as HEVC (H.265) instead of H.264.By @XilburQost

R Neil Haugen · Answer

Watching that, I was seeing some macro-blocking going on especially in some of the 'general' shadow areas, those place with a smooth surface. That's due to the way long-GOP compression works.

It looks at blocks of pixels, something like four, six, nine, whatever ... and if they are all pretty close ... say something like 25/29/42, 25/27/43, 23/29/44 ... it will probably 'simplify' data keeping by making them all just 25/29/42.

So slight gradients get lost, and you get adjacent pixel blocks of slightly different tone.

Which is where Averdahl's suggestions save your bacon ... and your pixels!

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