Crop area with size 100x100 at position (12,34).

crop=100:100:12:34

Using named options, the example above becomes:

crop=w=100:h=100:x=12:y=34

Crop the central input area with size 100x100:

crop=100:100

Crop the central input area with size 2/3 of the input video:

crop=2/3*in_w:2/3*in_h

Crop the input video central square:

crop=out_w=in_h
crop=in_h

Delimit the rectangle with the top-left corner placed at position 100:100 and the right-bottom corner corresponding to the right-bottom corner of the input image.

crop=in_w-100:in_h-100:100:100

Crop 10 pixels from the left and right borders, and 20 pixels from the top and bottom borders

crop=in_w-2*10:in_h-2*20

Keep only the bottom right quarter of the input image:

crop=in_w/2:in_h/2:in_w/2:in_h/2

Crop height for getting Greek harmony:

crop=in_w:1/PHI*in_w

Apply trembling effect:

crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(n/10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(n/7)

Apply erratic camera effect depending on timestamp:

crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(t*10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(t*13)"

Set x depending on the value of y:

crop=in_w/2:in_h/2:y:10+10*sin(n/10)