Digital windowing offers a distinct advantage over analog. it digitises the video image immediately, only converting it to analogue as it is sent to the CRT. Incoming composite video is digitised and decoded to produce a YUV data stream, which then enters the video-processing pipeline (color-space and format conversion, scaling and/or zooming). After processing, the data is stored in the frame buffer. At the appropriate time, the data moves to the overlay controller, which serves as a digital multiplexer.

Graphics data remains in digital form through the overlay controller; it is not converted to analogue until the final DAC that drives the CRT.