What is "ortho (vert/horiz) downscaling (bicubic)" and how can I change it from bicubic? or does it matter?

[marat569]

So I was watching a 3840x1600 movie on my 3840x2160 monitor, and noticed I had two shaders active:

ortho (vert/horiz) downscaling (bicubic)

I have no idea where they're from, scale/dscale/cscale are ewa_lanczos4sharpest

mpy mpv.conf: https://github.com/marat569/mpv.conf/blob/main/mpv.conf

so two questions:

1. what is that ortho thing doing
2. does it matter that its bicubic? I have performance to spare for something fancier than bicubic

When I googled the effect, I found only github issue with no solid solution

Also shoutout to Kasper93 -- my dude helps out with every post and issue

[hooke007]

dup #11841

[marat569]

dup #11841

So quick question:

1. Is bicubic for the two scalers perfectly fine? or is there a conf flag I can use to use something fancier?

Like I don't mind the scaling being there, my question is the fact that its using bicubic instead of something nicer -- unless whatever its doing doesn't really need anything fancy

[hooke007]

You'd better ask in that issue instead. DEVS always know more than users.

[marat569]

copy will do

[norinoriko]

b-spline (bicubic) is a smoothing filter and its only applied to the luma plane for feature extraction. it has no effect on chroma/rgb scaling and it's hard-coded, so you can't change it even if you wanted to. the only thing it does is map out the high-frequency and low-frequency information on the luma plane.

most feature extraction algorithms typically use either nearest neighbor, bilinear or b-spline. and out of those three b-spline is smoother and higher quality for feature extraction because it preserves source details while also not producing any unnatural jagged edges.

[marat569]

copy

I assume if its hardcoded, the impact it has on the image is negligible vs. something more "heavy"

[norinoriko]

bicubic is already computationally more "heavy" than both nearest-neighbor and bilinear.

[marat569]

bicubic is already computationally more "heavy" than both nearest-neighbor and bilinear.

What about the quality

I'm trying to say heavier as in looks better ( since stuff that looks better tends to be heavier ;p )

[norinoriko]

like I already said, bicubic produces a higher quality feature map than the other aforementioned interpolation methods. its just blending the low-frequency information to extract out the high-frequency details.

[marat569]

copy, I misread mb !

well I have no issue with the functionality then! if there is no quality loss, I trust mpv to do its thang!