Avisynth equivalent of VDub brightness/contrast/gamma

[Mephesto]

You should do brightness and contrast adjustments separately. Tweak can mirror your Vdub results with 99% accuracy, you just gotta figure out how to translate the numbers. Since we've already figured out how to do it for the filter I use, you should use it too if you wanna get your problem over with. Your tweak script should look something like this:

tweak(bright=-20)
tweak(cont=1.35, sat=1.35)

Saturation must be the same number as the contrast.

Appreciate input - No offense but its just got worse

Suddenly, I am in so love with vdub and filters - just wish I could do everything there!

Dude, I posted that script just to acquaint you with the proper syntax of the tool, I didn't mean for you to use those exact values.

These people say the Vdub filter you are using is % based. If that's true, time -55 by 2.56 and you get -141. That's your new Tweak number. Because of the RGB/YUV discrepancy, your number may be -121. Test it out.

For contrast, do some experimenting. Open a gray image in Vdub with a pixel value of 200. If your contrast setting changes the pixel to 240, your Tweak equivalent is 1.2.

[Mephesto]

That's not how they work in "regular" programs. Usually it's what you said: blacks blacker, whites whiter. There is a "contrast center" which is usually at the middle, but you can adjust it in some programs

How gay. Why did Vdub and Tweak take the weird route? I really hate experimenting with combos of more or less brightness, contrast and gamma just to fix a fudged up DVD (even Blu-ray) that release their shit highly under-saturated.

Also, before I forget: some values don't translate well to Tweak, such as 32 in my filter becoming 27.5. Does Tweak accept values with decimals? I input them in regardless but never did serious comparisons to see if they match.

[sreemv]

Provide some more information on the source format, what colorspace you are using (checkmark the show image formats box, in the video=>filters dialog box)

You should be able to get very very close with avisynth filters

Input is a MKV - used 4 filters total

- brightness/contrast shows YUV420
- levels, Color Mill and sharpen all show RGB32

[sreemv]

If you are only using brightness/contrast filter, you can stay in YUV in vdub

You can use x264vfw in vdub, you don't need external encoder (Unless you want aac audio). x264vfw can output mp4, mkv if you use the commandline box

Another option is to use vdub as a frameserver if you don't want large intermediate files (but it only frameserves RGB, not YUV)

I am not looking to process audio in vdub at all - Just want 2 pass x264 if I could.

Frameserve sounds like a good option - never used it. Will read up.

[sreemv]

Dude, I posted that script just to acquaint you with the proper syntax of the tool, I didn't mean for you to use those exact values.

These people say the Vdub filter you are using is % based. If that's true, time -55 by 2.56 and you get -141. That's your new Tweak number. Because of the RGB/YUV discrepancy, your number may be -121. Test it out.

For contrast, do some experimenting. Open a gray image in Vdub with a pixel value of 200. If your contrast setting changes the pixel to 240, your Tweak equivalent is 1.2.

Nothing personal, "dude" - Not sure what gave you the impression I tried your values literally - Not sure you are familiar with Avsp? It has sliders just like vdub filters and tried all different values...yes, I did get close but in darker scenes vdub looks cleaner than avs - just cant get any closer.

[jagabo]

Is this how Contrast generally works? I always thought increasing contrast meant widening the pixel differences, making blacks blacker and whites whiter. Both this Vdub and Tweak contrast formula actually make dark blacks a bit brighter.

That's not how they work in "regular" programs. Usually it's what you said: blacks blacker, whites whiter. There is a "contrast center" which is usually at the middle, but you can adjust it in some programs

VirtualDub's contrast/brightness filter works the way most analog TVs work. One control is the gain, the other the offset.

Y' = Y * Contrast + Brightness

[Mephesto]

Nothing personal, "dude" - Not sure what gave you the impression I tried your values literally - Not sure you are familiar with Avsp? It has sliders just like vdub filters and tried all different values...yes, I did get close but in darker scenes vdub looks cleaner than avs - just cant get any closer.

My bad. You said my script produced horrible results, so I assumed you couldn't have fine-tuned the script if it was that bad, and the numbers I inputted were far from what would yield close to what you were aiming for.

[jagabo]

tweak(bright=-20)
tweak(cont=1.35, sat=1.35)

Beware of doing this in two steps. If the first step crushes blacks or whites there is no restoring them in the second step. The order in which you perform the two steps is important (reversing the two commands will give different results). And "coring" is the default so you will lose anything below Y=16 or above Y=235 in each step if you don't specify coring=false.

The same is true for ColorYUV() except it doesn't core by default.