Phonofilm is an optical sound-on-film system developed by inventors Lee de Forest and Theodore Case in the early 1920s.
Phonofilm is an optical sound-on-film system developed by inventors Lee de Forest and Theodore Case in the early 1920s.
In 1919 and 1920, de Forest, inventor of the audion tube, filed his first patents on a sound-on-film process, DeForest Phonofilm, which recorded sound directly onto film as parallel lines. These parallel lines photographically recorded electrical waveforms from a microphone, which were translated back into sound waves when the movie was projected.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).