Yet another newbie w/ capture problem but at least its the last one...

[fumigator]

Hi everyone!
Got an amazing, used Philips VCR, with great picture quality, so I want to back up my vhs collection, History of aviation, soccer, birthdays, cartoons etc...

unluckly I have had many problems with my capture card but I won't bore you, lets make it short:

What I get is an overbrightened/overcontrasted area in the image, at the bottom as you can see in these pictures:

http://img181.imageshack.us/img181/8914/test29ek.jpg

http://img388.imageshack.us/img388/8703/test16tu.jpg

The solution I'm thinking after lot of searching is to use that Avisynthesizer thing, and to apply "tweak" to the strangely affected area. So I learned about it a bit and as I program in Pascal, I found the avisynth language quite easy, so I "programed" a script that goes like follows:

-------------------------------------------------------
#Dividing the image into clips A (top "good"-area)
#and B (bottom "too bright"-area)
A=crop(avisource("f:\captura\20060503-090458.avi",false),0,0,-0,-68)
B=crop(avisource("f:\captura\20060503-090458.avi",false),0,316,0,-0)

#Now, lower the brightness of the bottom part
tweak(B,0,0,-40,0)

#Stacking both together
source=StackVertical(A,B)

#returning the final video
return(source)
-------------------------------------------------------

So, far, it doesn't work:
I get the same picture untouched. Seems that "tweak" isn't working at all, I tried it by returning B only, I get the piece of image but no changes on it, no matter which number do I put in tweak.

So I tried to put tweak into "B=crop..." line and what I got is a black and white piece of bottom image (?!?!?!)

Couldn't have time to tweak anything else, hopefully someone could help me in this, maybe you can tell me a better way to treat this problem... or maybe you know the problem to my script.

Thank you :D

[AVIL]

Hi fumigator,

the line :

tweak(B,0,0,-40,0)

left clip B untouched (generally all avisynth filter left main clip untouched). Filtered clip, if no assignation is done, is left in a special clip called last.

sou if you changes

source=StackVertical(A,B) by source=StackVertical(A,last)

you get a changed clip.

After you are happy with the result you can optimize the script:

s=avisource("f:\captura\20060503-090458.avi",false)
A=crop(s,0,0,-0,-68)
B=crop(s,0,316,0,-0)


#Now, lower the brightness of the bottom part
#And stacking both together
source=StackVertical(A,tweak(B,0,0,-40,0))

#returning the final video
return(source)


Best regards

[fumigator]

Thank you very much AVIL, I tested out and at least I get something changed, but the B clip I get is total black, I even tried with 0 (unchanged brightness) without luck:

s=avisource("f:\captura\20060503-090458.avi",false)
A=crop(s,0,0,-0,-68)
B=crop(s,0,316,0,-0)
source=StackVertical(A,tweak(B,0,0,0,0))
return(source)

and I get a totally black B clip... where's the error? I'll try other things, I feel I get close to the final solution.

Also, can anyone recommend me which parameters to tweak because I feel its more of contrast than brightness... maybe both, or maybe other things?... who knows... I'll keep trying, thanks and waiting for comments :D

[AVIL]

Hi fumigator:

try with:

tweak(B,0,1,-40,1)

or more directly

tweak(B,bright=-40)

With tweak(B,0,0,-40,0)

you are setting saturation and contrast to minimum values (black image).

I recommend you to read avisynth documentation at

C:\Archivos de programa\AviSynth 2.5\Docs\english\index.htm

(in spanish)

in english perhaps :

C:\Program files\AviSynth 2.5\Docs\english\index.htm

Good luck.