AddBorders

Add black or colored borders, increasing frame size. This has several common uses:

• Adjust the aspect ratio (make a 4:3 clip into 16:9 without stretching)
• Splice a smaller resolution clip to a larger one without resizing
• Together with Crop, shift a clip horizontally or vertically – see below.

See also: Letterbox, which adds borders without changing frame size.

Syntax and Parameters

AddBorders( clip clip, int left, int top, int right, int bottom [, int color ] )

int  left, top, right, bottom = (required)

Border width in pixels.

• For YUY2 sources, left and right must be mod2 (divisible by 2).
• For YV12 sources, all four border widths must be mod2.

int  color = (black)

Border color; specified as an RGB value. See this page for more information on specifying colors.

• For YUV clips, colors are converted from full-range (0–255) to tv-range (16–235).

Examples and Notes

• Add letterbox (top and bottom) borders:

## add dark blue borders, using hex color notation
AddBorders(0, 86, 0, 86, $00008B) 

## same as above, using named preset color
AddBorders(0, 86, 0, 86, color_darkblue) 

• Be aware that many older lossy compression algorithms don't deal well with solid-color borders, unless the border happens to fall on a macroblock boundary (16 pixels for MPEG).

• Use AddBorders in combination with Crop to shift an image without changing the frame size:

# Shift an image 2 pixels to the right
Crop(0, 0, Width-2, Height)
AddBorders(2, 0, 0, 0)

Note, shifting this way must be done in 1- or 2-pixel increments, depending on color format.

You can shift in sub-pixel increments with Resize.