Pixelated/Blocky Effect in Smoke Render in Blender 2.82a?

Question

Here is my rendered output of a small sample to demonstrate the issue I'm having: https://gfycat.com/obedientkindlyguernseycow

When I look at any of this in Blender's rendered view, I don't see the blocky artifacts in the smoke that you see here. So I'm not sure how to fix this in my renders. Has anyone encountered this before? Viewport render is at 256 and the Render setting is 1024.

The domain was baked with 1024 Resolution Divisions with 12 max timesteps and 15 samplng substeps for the emitters.

I've also noticed that the effect is more pronounced in the animation output vs in my still renders. But I thought that each uses the same settings?

Answer 1

TL;DR,
Use png, exr, jpeg with high quality... image format to save as sequence and encode them in other program to video. eg. Adobe Premiere (Media Encoder), DaVinci Resolve

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Depend on your video encoder, keep in mind that most of the video format are lossy-compressed by default, which means some data are actually loss in the video from the source.

And most of the encoding algorithm assume that one frame should be similar to next frame, to reduce the space requisition for similar color. So if your explosion make "fast and high dynamic color change". Your video will perform a low resolution, or blur, chunk image sequence, if your video bit-rate is set as a relatively low value.

You can set your H.264 render parameter to lossless to suppress that mosaic effect:

Or you can use AVI Raw format to save a BMP-sequence-like video format.