On the studio and production side, it was entirely different. HD-MAC bandwidth reduction techniques bring the HD pixel rate down to the level of SD. So in theory, it would have been possible to use an SD digital video recorder, assuming it provides enough room for the DATV assistance stream, which requires less than 1.1 Mbit/s. SD video using 4:2:0 format (12 bits per pixel) needs 720x576x25x12 bits per second, which is slightly less than 125 Mbit/s, to be compared with the 270 Mbit/s available from a D-1 machine.