FixLuminance

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::Slope of correction function. The top of the picture is made darker by 1 (on a 0-255 scale) every {{FuncArg|slope}} lines.
 
::Slope of correction function. The top of the picture is made darker by 1 (on a 0-255 scale) every {{FuncArg|slope}} lines.
 
::Maximum darkening (at top line) = {{FuncArg|intercept}} / {{FuncArg|slope}}
 
::Maximum darkening (at top line) = {{FuncArg|intercept}} / {{FuncArg|slope}}
 
  
 
The purpose of this filter is to progressively darken the top of the image; for example, to compensate for certain VCRs which make the top of each frame brighter than the bottom. This filter works only with [[YUY2]] input.
 
The purpose of this filter is to progressively darken the top of the image; for example, to compensate for certain VCRs which make the top of each frame brighter than the bottom. This filter works only with [[YUY2]] input.
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==== Examples ====
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*Progressively darken top lines.
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<div {{BoxWidthIndent|48|2}} >
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[[ColorBars]](pixel_type="YUY2")
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[[Crop]](0, 0, 0, 256)
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FixLuminance(100, 4)
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[[File:FixLuminance1.png]]<br>
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Line 99 is normal; line 0, the topmost line, is darker by 25 ({{FuncArg|intercept}}/{{FuncArg|slope}} = 100/4 = 25)
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</div>
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*Make a ''ramp'' test image.
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<div {{BoxWidthIndent|48|2}} >
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[[BlankClip]](height=256, pixel_type="YUY2", color_yuv=$ff8080)
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FixLuminance(255, 1)
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[[File:FixLuminance2.png]]
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</div>
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[[Category:Internal filters]]
 
[[Category:Internal filters]]
 
[[Category:Levels_and_Chroma_filters]]
 
[[Category:Levels_and_Chroma_filters]]

Revision as of 03:51, 17 January 2016

FixLuminance(clip clip, int intercept, int slope)

int  intercept = (required)
Line at which to start correction.
int  slope = (required)
Slope of correction function. The top of the picture is made darker by 1 (on a 0-255 scale) every slope lines.
Maximum darkening (at top line) = intercept / slope

The purpose of this filter is to progressively darken the top of the image; for example, to compensate for certain VCRs which make the top of each frame brighter than the bottom. This filter works only with YUY2 input.

Examples

  • Progressively darken top lines.
ColorBars(pixel_type="YUY2")
Crop(0, 0, 0, 256)
FixLuminance(100, 4)

FixLuminance1.png
Line 99 is normal; line 0, the topmost line, is darker by 25 (intercept/slope = 100/4 = 25)


  • Make a ramp test image.
BlankClip(height=256, pixel_type="YUY2", color_yuv=$ff8080)
FixLuminance(255, 1)

FixLuminance2.png

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