For surround sound, there are some audio file formats that feature high audio quality and excellent separation of the individual channels. These include Dolby Digital and Digital Theatre Sound( DTS), but they require a high data rate and are often not backward compatible with existing mono and stereo receivers. Also, certain surround methods cannot be transmitted over the existing broadcast infrastructure. MPEG Surround is designed to eliminate these disadvantages.
MPEG Surround is an audio file format for the transmission of monophonic, stereophonic and surround sound, which can be combined with many audio coding methods; such as MPEG Layer-2, High Efficiency Advanced Audio Coding( HE-AAC) or MP3. Surround sound can be transmitted in all variants from 5.1 to 7.1 and 10.2 with minimal additional data rates of a few kilobits.
In principle, a multi- channel signal is mixed from the various audio channels, which can be played back in mono and stereo receivers. The additional surround information contains the information for the side and rear speakers and is obtained from the level differences, coherence and correlation values between the individual channels. This surround information can only be evaluated by appropriate surround receivers. The surround information is extracted during encoding, it contains the characteristic differences between the individual audio channels and is transmitted as pure data signals.
MPEG Surround is scalable and is characterized by high audio quality.