-do_lavfi "crop" "crop=100:100"
-do_lavfi "crop_scale" "crop=100:100,scale=400:-1"
-do_lavfi "crop_scale_vflip" "null,null,crop=200:200,crop=20:20,scale=200:200,scale=250:250,vflip,vflip,null,scale=200:200,crop=100:100,vflip,scale=200:200,null,vflip,crop=100:100,null"
-do_lavfi "crop_vflip" "crop=100:100,vflip"
+do_lavfi "crop" "crop=iw-100:ih-100:100:100"
+do_lavfi "crop_scale" "crop=iw-100:ih-100:100:100,scale=400:-1"
+do_lavfi "crop_scale_vflip" "null,null,crop=iw-200:ih-200:200:200,crop=iw-20:ih-20:20:20,scale=200:200,scale=250:250,vflip,vflip,null,scale=200:200,crop=iw-100:ih-100:100:100,vflip,scale=200:200,null,vflip,crop=iw-100:ih-100:100:100,null"
+do_lavfi "crop_vflip" "crop=iw-100:ih-100:100:100,vflip"