Sound film
The primary steps in the commercialization of sound cinema were taken in the mid- to late 1920s. At first, the sound films which included synchronized dialogue, known as "talking pictures", or "talkies", were exclusively shorts. The earliest feature-length movies with recorded sound included only music and effects. The first feature film originally presented as a talkie was "The Jazz Singer", released in October 1927. A major hit, it was made with Vitaphone, which was at the time the leading brand of sound-on-disc technology. Sound-on-film, however, would soon become the standard for talking pictures.
Audio commentary
The first audio commentary was featured on the Criterion Collection release of the original "King Kong" movie, on laserdisc in December 1984. It featured film historian Ronald Haver and his first words were:
The idea for the commentary track arose in the film-to-tape transfer room when laserdisc producers, Peter Crown and Jennifer Scanlin of Romulus Productions, Inc., thrilled by Haver's incredible commentary, suggested to Bob Stein and Roger Smith that this material needed to be included on the disc. They played back the completed movie as Ron watched and ad libbed his comments.