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| − | <div {{BlueBox2|40|0|3px solid purple}} >
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| − | {{AvsPlusFullname}}<br>
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| − | Up-to-date documentation: [https://avisynthplus.readthedocs.io/en/latest/avisynthdoc/corefilters/fixluminance.html https://avisynthplus.readthedocs.io]
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| − | </div>
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| − | ''Deprecated: see [[Talk:FixLuminance|discussion]]''
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| | {{Template:FuncDef|FixLuminance(clip ''clip'', int ''intercept'', int ''slope'')}} | | {{Template:FuncDef|FixLuminance(clip ''clip'', int ''intercept'', int ''slope'')}} |
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| − | :{{Par2|intercept|int|(required)}}
| + | My VCR has the annoying habit of making the top of each frame brighter than the bottom. The purpose of this filter is to progressively darken the top of the image to compensate for this. If you've noticed a similar problem with your VCR, email me and I'll finish this explanation of how the filter works. Otherwise, you can pretend it doesn't exist. |
| − | ::Bottom line at which to start correction. {{FuncArg|intercept}} should be equal to or smaller than the height of the image.
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| − | :{{Par2|slope|int|(required)}}
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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.
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| − | ::Maximum darkening (at top line) = {{FuncArg|intercept}} / {{FuncArg|slope}}
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| − | 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. In practice it only works for NTSC content and it needs its fields separated. | + | |
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| − | When applying it to an image with height > 255 pixels, you will see a repetitive gradient. So it doesn't work for field-separated PAL content.
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| − | This filter works requires [[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.
| + | This filter works only with YUY2 input. |
| − | <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]]
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