Ambient Surround Imaging
With Ambient Surround Imaging (AMSI) one is proprietary virtual surround sound process referred that in the Berlin Emil Studios was developed.
The AMSI method is particularly important when remastering mainly classical music and is used to provide existing stereophonic masters (i.e. material that is only available in two tracks) with artificially generated surround sound information.
The resulting material can thus be decoded by surround-capable hi-fi systems.
The exact functional principle is not known; However, it can be assumed that, similar to the Dolby Surround principle , AMSI generates a monaural surround sound channel from the existing stereo information by forming the difference and adds it to the existing stereo signal.
A further development of the AMSI process is known under the name AMSI II , which is only used for audio data on DVD-Audio , DVD-Video or SACD . Here, six discrete surround sound channels are generated from existing stereo material, thus creating a 5.1 signal as a Dolby Digital or DTS track. The AMSI-II process can therefore be referred to as an upmix process.