High Quality Content by WIKIPEDIA articles! RCA Photophone was the trade name given to one of four major competing technologies that emerged in the American film industry in the late 1920s for synchronizing electrically recorded audio to a motion picture image. RCA Photophone was a sound-on-film, "variable-area" film exposure system, in which the modulated area (width) corresponded to the amplitude of the audio signal. The three other major technologies were the Warner Brothers Vitaphone sound-on-disc system, as well as two "variable-density" sound-on-film systems, Lee De Forest's Phonofilm, and Fox-Case's Movietone. The patent was awarded to General Electric (GE) in 1925, which dubbed the process Photophone, a name that had been used in previous decades for other sound film processes. RCA, a GE subsidiary, took over the patent as part of a corporate competition with AT&T/Western Electric, a primary sponsor of both Vitaphone and Movietone.