std.CropAbs(clip clip, int width, int height[, int left=0, int top=0])
std.CropRel(clip clip[, int left=0, int right=0, int top=0, int bottom=0])

Crops the frames in a clip.

CropRel is the simplest to use of the two. The arguments specify how many pixels to crop from each side.

CropAbs, on the other hand, is special, because it can accept clips with variable frame sizes and crop out a fixed size area, thus making it a fixed size clip.

Both functions return an error if the whole picture is cropped away, if the cropped area extends beyond the input or if the subsampling restrictions aren’t met.