 Beginning in 1922, the research branch of Western Electric began working intensively on recording technology for both sound-on-disc and sound-on film synchronised sound systems for motion-pictures.The engineers working on the sound-on-disc system were able to draw on expertise that Western Electric already had in electrical disc recording and were thus able to make faster initial progress.The main change required was to increase the playing time of the disc so that it could match that of a standard reel of 35 mm film.