View Full Version : gamma on resizers


Dogway
2nd January 2011, 03:43
long ago I came to this (http://www.4p8.com/eric.brasseur/gamma.html) page where was explained the flaws of average scaling methods. So when I wanted high quality resizes Id choose float point based resizing in Photoshop, although narrowing the options to bilinear. Now that there are wonderful resizers in avisynth and some plugins work in float point (smoothadjust,dfttest), wouldn't it be possible to implement this?

PD: didn't want to dig grave the splineresize thread.

Lyris
2nd January 2011, 05:49
+1 - has anyone implemented linear light scaling in AviSynth?

jmac698
2nd January 2011, 08:39
I'm sure it could be done in masktools.
I doubt avisynth is gamma-aware.

LaTo
2nd January 2011, 11:26
Yes it's possible to implement this, but it will be slower...

Because all calculations will be at least in 16bits instead of 8bits (to avoid big rounding errors with gamma)

And most of the time the difference is small on real videos.

Gavino
2nd January 2011, 11:56
This has been discussed in the past:
http://forum.doom9.org/showthread.php?t=134192

Dogway
2nd January 2011, 13:38
Thanks for the link, I tried the photoresize function. Ignoring the scaling quality comparison many artifacts were introduced (ringing,red blocking in darks)
spline64 (http://img42.imageshack.us/img42/5585/spline64.png)
Photoresize (http://img337.imageshack.us/img337/7877/photoresize.png)
I guess they are waiting for Avisynth 2.6 (?)
I like using avisynth as an still image processor, I know I could do better moving to matlabs, but I come from the CG field, coding is not my strong...