Topic: SVP introducing some banding

I'm fairly new to SVP.  I'm using the AVI Synth Filter with the latest Madvr.  I've noticed some banding appear in scenes that don't show banding when "Temporarily disable SVP" is enabled.  I've included some screen snips that will hopefully demonstrate it.  Look at the sky.  Any ideas?

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svp-disabled.jpg, 48.05 kb, 626 x 431
svp-disabled.jpg 48.05 kb, 254 downloads since 2021-02-25 

svp-enabled.jpg, 68.89 kb, 611 x 529
svp-enabled.jpg 68.89 kb, 250 downloads since 2021-02-25 

Re: SVP introducing some banding

10-bit encoding? if yes, then check SVP -> App. settings -> Add. options -> Allow output in 10-bit color depth
note that 10-bit output doesn't work with EVR renderer

3 Reply by youngm (edited by youngm 25-02-2021 16:28:47)

Re: SVP introducing some banding

Same issue no matter how I set that 10-bit setting.  I'm using MPC-HC as the player and MadVR.  I think I only see the issue with 10-bit videos.  I didn't make that connection till I saw: https://www.svp-team.com/forum/viewtopic.php?id=6102

Re: SVP introducing some banding

> I didn't make that connection till I saw

he is using ffdshow, not AVSF, and ffdshow doesn't support 10-bit at all

could you share this sample? (torrent/magnet url is good too)

5 Reply by youngm (edited by youngm 26-02-2021 18:44:03)

Re: SVP introducing some banding

Ah, I didn't notice that.  K, I'll do a bit more testing with a few other videos to see if I can narrow the scope a bit more and I'll post a sample of this.  Thanks, Chainik!

6 Reply by James D (edited by James D 27-02-2021 01:33:49)

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Re: SVP introducing some banding

Just post a sample and there will be no need to do anymore testing. Chainik is looking about tech side of the video and not from where, how or what that video is.

7 Reply by youngm (edited by youngm 01-03-2021 03:55:20)

Re: SVP introducing some banding

So, I did a little more research and found that the banding was linked to enabling MadVR's HDR "Highlight Recovery" feature.  If I have SVP enabled and Highlight Recovery disabled then the banding goes away.  If I disable SVP and enable Highlight Recovery then the banding goes away.  If both are enabled then the banding appears.

Given the link to a specific MadVR setting, I'd understand if you didn't find it worth your while to research further.  But here are steps to reproduce it if you are interested:
* I'm using this version of MadVR: https://www.avsforum.com/threads/improv … t-60520084
* I'm using MPC-HC with AVSF
* I've attached an image of my MadVR settings that duplicate the issue.
* I've PMed you a link to the video clip.  Though I expect just about any HDR source will duplicate the issue with Highlight Recovery enabled.

Thanks!  Let me know if I can help in any other way.

Post's attachments

madvrsettings.JPG 237.08 kb, 150 downloads since 2021-02-28 

Re: SVP introducing some banding

Hmm....this problem doesn't seem to be exclusive to "Highlight Recovery".  I have a different set of settings (Highlight Recovery disabled) that looks fine in that clip of Croods 2 but produces banding in a different movie.  But, like the other banding, it goes away when I disable SVP.  If you want I can grab a clip and settings for that one as well.

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Re: SVP introducing some banding

dunno, I can't see any banding in 10-bit mode

---
note that by default SVP only allows 10-bit output up to 72 fps (because of performance issues)

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btw I just found that 10-to-8-bits conversion (if required) is made w/o dithering, it's probably a good idea to enable it
SVP 4\scrips\generate.js, line 356, replace

    AVS.push("ConvertBits(" + (media.p10 === true ? 16:8) + ")");

with

    AVS.push("ConvertBits(" + (media.p10 === true ? 16:8) + ", dither=0)");

or "dither=1"

If 0, add ordered dither;
If 1, add error diffusion (Floyd-Steinberg) dither doom9

Re: SVP introducing some banding

Well, I'm sad that you couldn't duplicate the issue.  But, turning on dithering seems to have fix the problem anyway!  So, thanks!

However, with dithering enabled, when I watch an 8-bit source I get the error "dithering is allowed only for 10-16 bit sources".  Perhaps there is some way to only enable that setting if it is a 10-bit video?

Re: SVP introducing some banding

> But, turning on dithering seems to have fix the problem anyway!

... which means you aren't using 10-bit output actually

> Perhaps there is some way to only enable that setting if it is a 10-bit video?

as a quick fix:

    AVS.push("ConvertBits(" + (media.p10 === true ? 16:8) + (media.src_fmt.endsWith("10") ? ", dither=0":"") + ")");

Re: SVP introducing some banding

Chainik wrote:

... which means you aren't using 10-bit output actually

Can you please help me understand what you mean by this?  I have "Allow output in 10-bit color depth" set to always.  Yet, in madVr stats it lists "l420,8 bit, 4:2:0" with SVP enabled.  With SVP "Temporarily Disabled" MadVR shows "P010, 10 bit, 4:2:0".  Is that what you are referring to? Do I have something configured wrong in SVP causing it to change the video from 10-bit to 8-bit?

My Display output is set to 8-bit in madvr.  But, I think I'd rather have madVR do the dithering over AVSF if possible.

Re: SVP introducing some banding

> Do I have something configured wrong in SVP causing it to change the video from 10-bit to 8-bit?

dunno... show SVP's log

Re: SVP introducing some banding

Thanks for confirming that it shouldn't be converting to 8 bit.  That gives me a concrete improvement to work towards.  I've attached some logs.  LMK if they are the wrong ones.  The plugins and media player wasn't installed by SVP.  If you think a stock install of all that would help I can give that a try.

Post's attachments

active.log 4.67 kb, 290 downloads since 2021-03-03 

opencl.log 7.3 kb, 280 downloads since 2021-03-03 

Re: SVP introducing some banding

Ah, I figured it out!  I had "GPU Acceleration" turned off.  Once I turn that on then SVP doesn't convert the video to 8-bit.