How to clip brightness with VirtualDub?

[FredThompson]

I'm looking for something like an inverse core routine that will limit the brightness. Level won't do the job properly, it rescales the entire frame. Is there a filter to do this or must I use AviSynth?

[rfmmars]

What you want is EOD's "Autolevels" many presets!

Can be found on Donald Graft's site. http://neuron2.net/index.html

richard
photorecall.net

[Guest]

Originally posted by rfmmars
Can be found on Donald Graft's site. EOD's site is gone. :(

[rfmmars]

Did it just go down like yesterday? I think I download it again yesterday from your site. OK i will make a note of it.

thanks

richard

[FredThompson]

That's a little different than what I'm looking for. I just want to clip the brightness, not rescale.

The site has moved to: http://eodvdf.narod.ru

There's an improved version as well.

[trevlac]

@Fred

Would 2 Levels in a row work for you?

1st move black level up. This should clip the white.
2nd move black back down. White is still clipped.


Something like:
Levels(input_low=0,output_low=16)
Levels(input_low=16,output_low=0)

[FredThompson]

That just might work and it's quite appealing because it's a clever use of internal routines. I'll give it a shot. Thanks.

[rfmmars]

I notice the site is down......If you can't find it, give me a e-mail at rfmmars@cox.net

richard

[FredThompson]

Which site is down? EOD moved the page to the address I showed above.

I played with the levels command and it does do the task. Unfortunately, there was too much flattenging going on so now I'm going to experiment with the value-specific filter whose name escapes me at the present time. Basically, you put a new value in for each of the possible existing brightnesses. Perhaps a weighted-scale reduction will help lower the overall brightness and maintain a little more detail then just clipping. Settings all those values by hand is a pain int he butt, though.

[rfmmars]

Please keep me infromed on the filters you like, the one you just mention sounds neat. The site listed on Donald Graft's site was the one down as of yesterday.

thx

richard

[trevlac]

I think Fred is speaking of the gradation curves filter by BugsBunny.

If he would only fix the interface. :)


Actually, to do a proper curves interface, you have to know a lot. Drawing a curve would require the use of a spline (draging the line around). If you use built in windows functions, you would have to get the point values back out so you could use them in the filter. Not to mention the issue of determining if someone actually clicked on a curved line. Not as easy as one might think.

I'd like him to fix it so I can see how he does all of that.

[FredThompson]

Yeah, that's the filter, alright.