vu-transpose		transpose frames
vu-blur			gaussian blur, -c to only blur chroma
vu-transform		transformation by matrix multiplication, -t for tiling, -s for improve quality
				on downscaling (pixels' neighbours must not change)
vu-chroma-key		replace a chroma with transparency
vu-primary-key		replace a primary with transparency, -g for greyscaled images
vu-from-video		use ffmpeg to convert from another format
vu-to-video		use ffmpeg to convert to another format
vu-primaries		given three selectable primaries split the video into three side-by-side which
				only one primary active
vu-crop			crop video, -t for creating tiling instead of cropping
vu-extend		extend the video on which side with transparency, , -t for tiling
vu-distort-map		remap pixels using the X and Y values, -t for tiling, -s for improve quality
				on downscaling (pixels' neighbours must not change)