Which resize to use

[jpsdr]

Hello.

i've a question.
About the several resize avaible :
LanczosResize (=lanczos 3)
Lanczos4Resize
Spline16Resize
Spline36Resize
Spline64Resize

Wich one is good? (If there is one). Speed is not an issue.
Is there one better for upsampling, and another better for
downsampling ?

For doing :
Upscale 480 -> 576, wich one is good?
Upscale 480 -> 720 : Same as 576, or another ?
Downscale 1080 -> 576 ? Wich one is better ?
Same, downscale 720 -> 576 ?

:thanks:

[StainlessS]

No expert, and some of the newer resizers, I have never used, but,
I would use BilinearResize() for downsizing, and Lanczos4Resize()
or perhaps one of the Spline Resizers for upsize. Note however that
the upsizers mentioned do produce some sharpening and hence may
compress less well for a given bitrate. Maybe for upsizing with good
compression, it is still advisable to use BlinearResize or perhaps
BicubicResize() with args b and c both (1.0/3.0).
You cant really beat trying stuff out, use StackHorizontal() (or vertical)
to compare output side by side, there are rarely any hard and fast rules,
if there were, there would be little point in giving you a wide choice of
options.

Gud luk :)

[thetoof]

close to .5 downsize - .5 downsize with automttap3 (part of sssharp), very sharp with halo prevention, and then spline36 (neutral) to the desired size
close to 2x upscale - 2x with nnedi2_rpow + spline36 to the desired size

The rest - (small ajustments) = spline36

But heh, that's just my personal preferences... so yes, it'll be slow.

[jpsdr]

Thanks for these informations, i'll try this.
What are automttap3 and nnedi2_rpow, and where do you get them ?

Edit : I think i've find out things.
nnedi2_rpow is in nnedi2 v1.4, am i right ?
automttap3 is the script here : http://forum.doom9.org/showthread.php?p=1010146 (script post #49). Am i correct also ?
If yes, what paramater do you use for mtaps3 and thresh ?

[jpsdr]

For upscaling, for exemple, 720x480 -> 1280x720 would you do :

nnedi2_rpow2(2)
Spline36Resize(1280,720)

Or the following :
nnedi2_rpow2(rfactor=2,cshift="Spline36Resize",fwidth=1280,fheight=720)

For downscale (1080->575 for exemple) i think it's :
c=AVISource("File.avi")
automttap3(c.width*0.5,c.height*0.5)
Spline36Resize(720,576)

[thetoof]

nnedi2_rpow2(rfactor=2,cshift="Spline36Resize",fwidth=1280,fheight=720)This one.

For downscale i think it's :Yes.

[ronnylov]

For downscale (1080->575 for exemple) i think it's :
c=AVISource("File.avi")
automttap3(c.width*0.5,c.height*0.5)
Spline36Resize(720,576)

But then I think it is downscaling and then upscaling and loosing some resolution (1080/2=540 upscaled to 576). Is this really better than a straight spline36Resize directly from 1080 down to 576?

What about upscaling to 1152 first with Spline36Resize and then automttap3(c.width*0.5,c.height*0.5)?

[thetoof]

You'll have to test for that. (both straight spline36 vs automttap3 and upscale + automttap3 downscale)

When the source has great sharpness, you can notice the difference, otherwise not at all.

[jpsdr]

As it is intended for working in anime, i want to keek the sharpness as much as possible.
Thanks for these suggestions, i'll try and test them.