Dolby Digital film format, developed for encoding audio tracks for films. It supports up to 6 audio channels: left, right, front, rear, upper and lower. Because of this, it allows you to store “3-dimensional” audio tracks. It’s widely used both in movie theaters and by the users themselves for storing audio tracks in film libraries at home.

This format was originally intended for voice compression and is able to change the bit rates of encoded audio data. AMR is actively used for encoding and decoding voice while its being transmitted over network channels. The format allows one to consider network capacity and adapt it to channel loads. Due to this, the voice quality is practically undiminished.