Video Quality Lost - Input to Output

[Zoltán]

Well, if you rotate the 10x10 px slice without scaling, you can see the bleed on your output still, even with pixel perfectly aligned slices.

In v5 you could choose between tri-linear and nearest neighbor scaling in preferences. Resolume now uses tri-linear on the output (since v6). With the nearest neighbor mode, the bleed doesn't seem to happen in 5.

Switching back to nearest neighbor scaling would have pixelated scaling results, it could be worse than having 1 px of bleed.

If you'd need to choose, - and as this hasn't come up in the few years where Resolume 6 an 7 was out, - I'd guess the bleed is a lesser issue than pixelation, right?

240x200px slice scaled up to 1080p:
tri-linear:

nearest neighbor:

[Joris]

Ooooooh, that's interesting. Sure, smoother scaling is probably the better option for the majority of the Resolume user base.

When you're trying to work pixel accurate on LED, the difference between a color accurate pixel and a pixel with bleed is pretty noticeable. I've spent a lot of time fudging slices by half a pixel to get rid of strange colors at edges and weird black seams where slices were stitched together. At least good to know what the cause is, this has had a few of us baffled for a while now. It was especially weird because at a festival with a setup that had this problem, every VJ running Resolume needed the same fudging, but those with other systems didn't.

[francoe]

I've spent a lot of time fudging slices by half a pixel to get rid of strange colors at edges and weird black seams where slices were stitched together.

Yes!! When people send me the leds pixel map's scheme I allways redesign my output to deal with those bleedings. I use to make all my slices 4px smaller to avoid the color overflow.

[Zoltán]

Hmm, so it would be better to have the option to choose...

[Zyper]

I was sure this will end on some interesting discussions. Zoltan you're so right ! good point, didn't check the output.

For Res 5 i was using the no blend solution as I was working a lot with P40 and P20 Led walls. Was looking much better with custom made content. But didn't use it since.

The windows scaling option should be better mentionned in resolume, I'm sure this happen to a lot of people without knowing where the problem comes from.

Up to my next Question about video quality :

4k comp with 4k layer playing 4k content with/without 4k slice transform.

Without slice transform quality is perfect.
With slice transform (who doesn't scale anythin) I'm loosing quality.

Is that an algorithm thing or I'm missing something ?

[Zoltán]

Without slice transform quality is perfect.
With slice transform (who doesn't scale anythin) I'm loosing quality.

Could you post a screenshot of how the slice transform effect is set up?
Thanks!

[avclubvids]

There does not seem to be a lot of recent info on this so I guess I am re-opening this topic somewhat. I have an LED surface that I want to send pixel-accurate video to. The LED is 896px * 840px, so I created a new Screen with this exact resolution and sent some video to it, but everything is getting a ~1px filter applied to it despite no scaling being applied anywhere. See attached screenshots below of a crisp checkerboard grid input and a fuzzy filtered checkerboard output. I see mention of filter selection in earlier versions of Arena; specifically, I would like to turn on Nearest Neighbor but I cannot find where this option is in the current version of the software.

Is there a way to turn off this output filtering, or to guarantee that the input and output are identical?

[Christoph]

No scaling applied anywhere applies to everything inside Arena I guess. Did you also make sure that ALL displays are set to 100% display scaling in Windows display settings?

[Menno]

I believe all the edge issues posted here in 2020 have been resolved in the meantime. The screen setup is now no longer sampling anywhere near neighboring pixels outside of the slice, preventing those pixels from being filtered in. I believe this is the best of both worlds, no bleeding while using linear filtering for scaling. If anyone still has this bleeding or needs to apply their half-pixel offset workarounds or any other kind of shenannigans please let us know.

There's three issues closely related to this thread i'd like to solve but cannot reproduce without involving external devices:

• The one that breaks most shows is the one where users of led-processors are still getting the bleeding between slices. This is especially noticable there because the layout in the output does not match the physical layout in the real world, and thus the bleeding will include colors from the other side of the stage.

• Another one which i cannot reproduce is some kind of fuzzyness when using HDMI outputs. I cannot get this just with displays attached to my gpu. The latest hunch here is that this might be related to some optimus based setups with the output connected to the gpu not being used by Resolume. For this one i'd like to get a repro where screenshotting a display also shows the fuzzyness. The problem here is that once a frame is handed of to the OS for presentation to the display it's out of our hands what it's doing with our pixels.

• The last issue is that of the multi-monitor dpi awareness. You can have multiple monitors connected all with different dpi which you can then apply scaling to on the OS level to make applications end up with the same physical size again. Applications that are not aware of dpi are automatically scaled by the OS. Currently Resolume is not DPI aware and so you have to use 100% desktop scaling for all outputs (including the ui display).

@avclubvids: It seems you are experiencing a slightly different filtering issue. This time inside the slice, instead of on the edges. This is very interesting as i can see the screensetup itself already experiences this issue so no external devices involved. I believe it may be a bug. We no longer support turning of filtering but you may be able to turn it off in the driver settings while this issue is being investigated.

[avclubvids]

Do you have a manual page or guidance on which driver settings to adjust in which manner to temporarily solve the filtering issues I posted? I am currently running on an M3 Macbook Pro so if it is an NVIDIA driver or preferences that is not applicable. But perhaps the M3 / metal thing is a clue as to why this is happening?