The 1924 introduction of an editing machine called the Moviola facilitated movie production . This machine, which used a variable-speed electric motor and pedal control, was an innovation that made it much easier to splice footage together. As a result, movies became faster-paced, with a shorter average shot-length.
Multi-track sound was introduced in some cinemas for the first run of "Fantasia" in 1940, but thereafter was used little until stereophonic sound came in with CinemaScope and other widescreen formats in the 1950s. At about the same time, use of magnetic recording began. In addition to having higher fidelity than optical recording, it had the significant advantage of instant playback on the set. In the 1970s, Dolby noise reduction techniques came into use, both in movie-making and cinema presentation.