FixLuminance

Deprecated: see discussion

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)

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)