Caption: Axel Petersen and Arnold Poulsen, 1923.

Optic Sound

Optic sound for film was first demonstrated by the Danes Axel Petersen and Arnold Poulsen in 1923 (October 10). At this time, images were on one film, and the sound was printed on another. Later, both mono sound and images reached the same strip of film.
Dolby Stereo was introduced in 1975 as an analog, optical track on the film.
Dolby Digital + Spectral Recording for analog tracks was introduced in 1992.
DTS, Digital Theatre Systems, demonstrated digital audio for movies in 1993. The first movie with DTS was Jurassic Park, released in 1993. 
SDDS, Sony Dynamic Digital Sound, was introduced in 1991. The first film was published with SDDS: Last Action Hero on June 17, 1993. 

Magnetic Sound

Magnetic Sound on film has been used for 70 mm (6 tracks) or the consumer format 8 mm Super 8 (one track). The problem with the magnetic sound was primarily the durability due to wear and tear of the magnetic coating of the celluloid-based film.

Digital Sound

As mentioned above, the first digital soundtracks for the film were printed as optical information or an optically printed timecode.
Today, the film is stored on hard discs and streamed from the film company to the movie theatre, where it is stored locally for presentation. No physical media is used.

Caption:
A: SDDS (corresponding tracks are found on the opposite edge of the film).
B: Dolby Digital
C: Analog soundtracks (Dolby Stereo).
D: DTS soundtracks (timecode for CD-ROM) on 35 mm film.