(MPEG Surround) is efficient technology for multi-channel audio compression. Rather than performing a discrete coding of the individual audio input channels, MPEG Surround captures the spatial image of a multi-channel audio signal into a compact set of parameters that are used to synthesize a high quality multi-channel representation from a transmitted downmix signal. MPEG Surround extends traditional techniques for coding of two or more channels in a way that provides several significant advantages in terms of compression efficiency and user benefits. Firstly, it allows the transmission of multi-channel audio at bitrates, which so far have been used for the transmission of monophonic audio. Secondly, by its underlying structure, the multi-channel audio signal is transmitted in a backward compatible way, i.e. the technology can be used to upgrade existing distribution infrastructures for stereo or mono audio content (radio channels, Internet streaming, music downloads, etc.) towards the delivery of multi-channel audio while retaining full compatibility with existing receivers.
