Avisynth: what's wrong?

[PeterNL]

Hi,

Trying to get the max RGB levels of a clip.
I have this after splitting the clip into RGB:

Scriptclip(clip,"
r = YplaneMax(RE)
g = YplaneMax(GR)	
b = YplaneMax(BL)

max = (r >= g && r >= b) ? r : (g >= b) ? g : b)
")

Somehow the conditional will not work. What I'm doing wrong?

[LigH.de]

ScriptClip allows calling one function. One function. Your example might work if you declare this whole snippet as a function to call it.

But wait ... what does it do? The function YPlaneMax() returns the maximum of the Y plane. Are the clips RE, GR, and BL calculated before? Is the value in max used in further calculations?

[raffriff42]

It works if you make the following changes:

clip=clip.ConvertToRGB32
RE=clip.ShowRed  ("YV12")
GR=clip.ShowGreen("YV12")
BL=clip.ShowBlue ("YV12")

Scriptclip(clip,"""
r = YplaneMax(RE)
g = YplaneMax(GR)   
b = YplaneMax(BL)

max = (r >= g && r >= b) ? r : (g >= b) ? g : b #) ## extra closing paren omitted 
""")

BTW, the last line can be replaced with

max=Max(r, g, b)

And you won't see any result out of this ScriptClip unless you insert something that uses max, like for example:

Subtitle("max="+String(max))

EDIT added triple quotes (""") around ScriptClip, always recommended

[jagabo]

And keep in mind that the scope of the variable max is only within ScriptClip.

[PeterNL]

But wait ... what does it do? The function YPlaneMax() returns the maximum of the Y plane. Are the clips RE, GR, and BL calculated before? Is the value in max used in further calculations?

I use it for sort of autochroma leveling. The clip is splitted in RGB parts first (RE,GR,BL). Then I need to know which of the three has the highest level R, G or B.
After that I use autolevels to adjust all three with a same amount so the relation between R,G and B stays the same but optimized.
Say the clip has a RGB of 220,230,240. After leveling it will be 235,245,255 (I use full range).

So, I need to find which channel (R,G,or B) has the highest value.

Here's the complete script:

LoadPlugin("plugins/Autolevels_06.dll")

#clip=Avisource("D:/temp/test.avi")
clip=Avisource("F:/Videos/Bronmateriaal/amerika 1983/amerika_origineel.avi")


clip=clip.ConvertToRGB24()
#source=source.ConverttoYV12()

RE = clip.ShowRed().converttoYV24()
GR = clip.ShowGreen().converttoYV24()
BL = clip.ShowBlue().converttoYV24()

Scriptclip(clip,"
r = YplaneMax(RE)
g = YplaneMax(GR)	
b = YplaneMax(BL)

r >= g && r >= b ? max=r : g >= b ? max=g : max=b)	# find greatest channel
subtitle(string(max),size=48)		#test

diff = 255 - max

RE = RE.Autolevels(coring=true,sceneChgThresh=100,filterRadius=5,output_low=0,output_high=r+diff,ignore_low=0.005,ignore_high=0.0001)
GR = GR.Autolevels(coring=true,sceneChgThresh=100,filterRadius=5,output_low=0,output_high=g+diff,ignore_low=0.005,ignore_high=0.0001)
BL = BL.Autolevels(coring=true,sceneChgThresh=100,filterRadius=5,output_low=0,output_high=b+diff,ignore_low=0.005,ignore_high=0.0001)

MergeRGB(RE,GR,BL)

")

[PeterNL]

It works if you make the following changes:

clip=clip.ConvertToRGB32
RE=clip.ShowRed  ("YV12")
GR=clip.ShowGreen("YV12")
BL=clip.ShowBlue ("YV12")

Scriptclip(clip,"""
r = YplaneMax(RE)
g = YplaneMax(GR)   
b = YplaneMax(BL)

max = (r >= g && r >= b) ? r : (g >= b) ? g : b #) ## extra closing paren omitted 
""")

BTW, the last line can be replaced with

max=Max(r, g, b)

And you won't see any result out of this ScriptClip unless you insert something that uses max, like for example:

Subtitle("max="+String(max))

EDIT added triple quotes (""") around ScriptClip, always recommended

Thanks for your tips!
Never thought of that "Max". Much easier than the crap I had....

[PeterNL]

And keep in mind that the scope of the variable max is only within ScriptClip.

....and no way to get it out? Global? Would make life easier....

[raffriff42]

RE = clip.ShowRed().converttoYV24()
GR = clip.ShowGreen().converttoYV24()
BL = clip.ShowBlue().converttoYV24()

Scriptclip(clip,"
r = YplaneMax(RE)
g = YplaneMax(GR)   
b = YplaneMax(BL)

/*
r >= g && r >= b ? max=r : g >= b ? max=g : max=b)  # find greatest channel
#                     ^                ^       ^ ^  ## (4 syntax errors)
*/
## REWRITTEN
max = (r>=g && r>=b) ? r : (g>=b) ? g : b  # find greatest channel

## REWRITTEN AGAIN
max = Max(r, g, b)  # find greatest channel

subtitle(string(max),size=48)       #test
## ABOVE HAS NO EFFECT (OVERRIDDEN BY MergeRGB BELOW)

diff = 255 - max

RE = RE.Autolevels(coring=true,sceneChgThresh=100,filterRadius=5,output_low=0,output_high=r+diff,ignore_low=0.005,ignore_high=0.0001)
GR = GR.Autolevels(coring=true,sceneChgThresh=100,filterRadius=5,output_low=0,output_high=g+diff,ignore_low=0.005,ignore_high=0.0001)
BL = BL.Autolevels(coring=true,sceneChgThresh=100,filterRadius=5,output_low=0,output_high=b+diff,ignore_low=0.005,ignore_high=0.0001)

MergeRGB(RE,GR,BL)
subtitle(string(max),size=48)       #test (MOVED DOWN)

")

And keep in mind that the scope of the variable max is only within ScriptClip.

....and no way to get it out? Global? Would make life easier....

It is a per-frame variable, therefore it must be used in a run-time filter like ScriptClip.


EDIT by the way, it sounds like you might want to try ColorYUV(autowhite=true, autogain=true) or, for nicer results, GamMac ["Gamma Machine"].