Dolby 3D Movie Return Trailer Flat 3D (2D) 4K DTS-HD MA 5.1 with download link

Dolby Digital is the name for audio compression technologies developed by Dolby Laboratories. Originally named Dolby Stereo Digital until 1994, except for Dolby TrueHD, the audio compression is lossy. The first use of Dolby Digital was to provide digital sound in cinemas from 35mm film prints; today, it is now also used for other applications such as TV broadcast, radio broadcast via satellite, DVDs, Blu-ray discs and game consoles.

Dolby Digital;

Dolby Digital is the common version containing up to six discrete channels of sound. The most elaborate mode in common use involves five channels for normal-range speakers (20 Hz – 20,000 Hz) (right, center, left, right surround, left surround) and one channel (20 Hz – 120 Hz allotted audio) for the subwoofer driven low-frequency effects.[11] Mono and stereo modes are also supported. AC-3 supports audio sample-rates up to 48 kHz.

This format has different names:

Dolby Digital
DD (an abbreviation for Dolby Digital, often combined with channel count; for instance, DD 2.0, DD 5.1)
AC-3 (Audio Codec 3, Advanced Codec 3, Acoustic Coder 3. [These are backronyms. Adaptive Transform Acoustic Coding 3 is a separate format developed by Sony.])[12]
ATSC A/52 (name of the standard)[13]
Before 1996, was marketed as Dolby Surround AC-3, Dolby Stereo Digital, and Dolby SRD.[14]

In 1991, a limited experimental release of Star Trek 6 in Dolby Digital played in 3 US theatres.[14] In 1992, Batman Returns is the first movie to be released in Dolby Digital.[15][16] In 1995, the LaserDisc version of Clear and Present Danger featured the first home theater Dolby Digital mix, quickly followed by True Lies, Stargate, Forrest Gump, and Interview with the Vampire among others.[17][18]