Color Fringes with DXV

[rolandmc]

The short of it: Does encoding to DXV cause color fringing/video moires in content? See the attached photo for an example of what I mean. It's an exaggerated example, but we have all seen those "ridges" pop up in certain types of content, usually when viewing the sky.

The long of it: I recently had 1080p content delivered to me for a film shoot and, upon playback on the LED wall, similar "ridges" (or video moires, whatever you want to call them) showed up in the sky portion of the content and it sparked a big discussion: The content creation team of course wanted to blame the DXV codec for this and, while I'm skeptical that that's true, I wanted to ask about it here.

What causes this? I know it has to do with compressing the video, but is it endemic with the DXV codec? Is there a way to avoid this in the future?

For some background information: The content creation team encoded it with a different codec (not sure which one) and then used Alley to get it into the DXV codec.

Thank you for any insight you can give.

[resolumejunkie]

I work in filmmaking, but am not an LED wall expert. Arvol is and will chime in.

A couple of thoughts:

(1) I am of the opinion that even the 10-bit version of HAP isn't good enough for this.

(2) 8-bit DXV is definitely not good enough for this.

(3) It's not just the file format. It's the software, hardware, cables, video processor, and LED tiles.

Bottom line:

Eliminating banding is quite expensive. And, they likely will have sticker shock.

EDIT:

Question... how did you create the banding example? I like that effect. Is that from ShaderToy?

2ND EDIT:

Some scientific findings:

https://help.disguise.one/Content/Getti ... Codec.html

https://dandelion-burdock.com/articles/ ... -viability

[Arvol]

Could you share the original file and then the dxv converted file? Looks to be an encoding issue to me.

[Zoltán]

Try DXV HQ.

[rolandmc]

I have shared the final file with Arvol, although unfortunately I do not know what the content team started out with, I just know that they encoded it to something (probably ProRes), then used Alley to get it into DXV. You can definitely notice these moires in the sky when playing back with Alley (although they're quite subtle).

I was also of the mind that it has a lot to do with the LED wall and processing as well, but I'm not sure how much. Can Resolume play TIFF files at 1080p? Even if it has to be at a smaller resolution to play smoothly, it might make sense to try that with some other content to see if I can replicate the effect.

@resolumejunkie, I did not make the banding example myself, someone else made it, sorry! Thank you for the Dandelion link, it's been really helpful.

@Zoltan What is DXV HQ? I am not familiar.

Thank you all for your input.

[He2neg]

DXV does exist with different "quality" lvls... HQ is the highter one... you can chose inside alley to what you want to convert... Filesize will be bigger.

other points here mentioned are also need to take care off: Hunting down this fail to the exact point is a long way

do you see these effect on your screen as well or only on the led wall?
what is the resolution of the led wall... mostly their is some scaling happening and this can couse some bad results as well...
does them apear in moving picture only or also inside a still frame?


you also can run some test content and look if you see a misstake as well, like TESTCARD

[rolandmc]

Oh of course. Yes, it was rendered in High Quality... I read DXV HQ as DXV Headquarters

@he2neg The fringes are apparent on my laptop screen right now, and also when I pause the content. I can't remember the LED wall resolution, but it was significantly smaller than 1080p. I mapped it natively with Resolume and then scaled the content down with the software.

[He2neg]

Oh of course. Yes, it was rendered in High Quality... I read DXV HQ as DXV Headquarters

@he2neg The fringes are apparent on my laptop screen right now, and also when I pause the content. I can't remember the LED wall resolution, but it was significantly smaller than 1080p. I mapped it natively with Resolume and then scaled the content down with the software.

Also when some scale down is performed its possible to have strange behaviours... but when you see the same on all outputs and screens then its not a scaling thing. you can plug a native 1080p screen and use this as test output if you want to be sure. also the hz should match (content - output - screen)

How did you recive the file? I once had a download via some online storage and it was so hard compressed while downloading the file was trash after download.

Somewhere in the history of the file something went wrong Can be a lot of stuff...

[Zoltán]

So, got your file from Arvol, indeed really hard to say where things went wrong with the colors. The video is also looking quite underexposed. Is it supposed to be HDR? Looks a lot like the shot on the right here http://resolume.com/forum/viewtopic.php?p=85381#p85381

Can you upload the original file your team converted to DXV?