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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 color_yuv AVS+])

int  left, top, right, bottom = (required)
Border width in pixels.
  • For YUY2 and YV16 sources, left and right must be mod2 (divisible by 2).
  • For YV411 sources, left and right must be mod4 (divisible by 4).
  • 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).
int  color_yuv =
Specifies the color of the border using YUV values. It requires setting pixel_type to one of the YUV formats; otherwise it doesn't do anything.
Similar to color_yuv in BlankClip

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) 

## full scale black border using color_yuv hex color notation
AddBorders(0, 86, 0, 86, color_yuv = $008080) 
  • 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.
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