1 Topic by clidx (edited by clidx 16-01-2021 12:54:05)

Topic: Artifacts around lines

"artifacts" is the best way I have to describe it but maybe that's not accurate. Sometimes it looks like overshoot, sometimes stuttering/flickering but only specific parts of the frame, sometimes like somebody opened Photoshop and went mad with the liquify tool. Examples are attached. This doesn't happen with h.264 content - these stills are from a h.265 video transcoded from h.264 source. It happens with both the ffdshow raw filter and avisynth script but not with SVP closed. I use MPC-BE with madVR but it also happens in Plex and MPC with EVR instead of madVR. Specs are 5800X and RTX 3070 so performance is unlikely to be the problem. Plus the h.265 videos are much lower bitrate than the h.264 sources.
I think artifact masking helps a little bit but not much.
There's nothing of note in the event log.
Any way to fix this?

OK, just spotted it happening in an AVC file too. So it's not codec related and may just be coincidence that it happens more on my HEVC files. But I have noticed that it relates to lines... somehow. But I guess smoothing the movement of lines is how SVP works anyway.

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Re: Artifacts around lines

Anybody?

  • MAG79
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Re: Artifacts around lines

It is "waved" artifacts. All interpolation algorithms has artifacts. You can make the artifacts less visible but can't eliminate them completely.
More information in this forum:
Artifacts issue  1906
Subtitle flickering 1407
Waved artifacts on DVD 1312

I use some trick to get this artifacts less visible:
1.  72Hz and 75 Hz custom refresh rate with x3 interpolation ratio.
2. Another SVP-shader with "block" artifacts instead of "waved" artifacts. Them less visible to my eyes.
My SVP Profile settings:
- Frame interpolation mode: Uniform
- SVP shader: 10. By blocks
- Artifacts masking: Disabled
- Motion vectors precision: Half (But for anime it can be One or Two pixels)
- Motion vector grid: 12px (But for anime it can be 24px or 28px)
- Processing of scene changes: Blend adjacent frames

4 Reply by clidx (edited by clidx 23-01-2021 11:48:59)

Re: Artifacts around lines

Currently I have it set to fixed 60fps. It is a 4k tv which goes up to 60hz and refuses to run at 48hz via custom resolution. So double ratio or 48fps at 60hz will have to do. It's a bit better at x2 but still very noticeable.

Frame interpolation mode: couldn't find it in settings nor in the manual
fi_shader to 10. Is by blocks = 10 or a separate setting?
Arifacts masking I've left on medium for now because it's nearly unwatchable when off
I was unable to set fi_precision to 0.5 from 2, it needs to be an integer.
fi_grid is already 12
fi_scene_changes is an integer, not sure what number that setting is? It's not in the manual.

With these settings it's better but still very noticeable. I normally use svp on Linux and have done for several months and the artifacts have been very minimal on default settings and fixed 60fps. I started using svp on Windows for HDR and that's when I noticed it (although most of the videos I've tried haven't been HDR and that's not related to this issue). Maybe the default settings are different? I also upgraded my R5 2600 to R7 5800X almost exactly at the same time but the system passes all stress tests for a few hours (small FFTs prime95 etc) with the 5800X so I don't think it's instability.

  • MAG79
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Re: Artifacts around lines

You need to add new profile.
https://www.svp-team.com/wiki/Manual:FRC
Then you will find these profile setting.

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