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spatial audio coding (MPEG) (SAC)

Spatial Audio Coding(SAC) is an audio compression in which the two stereo or several audio channels are combined into one mono channel. Additional information of the different audio channels is transmitted in another channel. This can be the phase positions, volume differences or other spatial sound information. SAC coding is one method that works with Parametric Stereo( PS), another is Binaural Cue Coding( BCC).

Due to the sophisticated SAC technique, the bit rates of 128 kbit/s to 192 kbit/s for spatial information are relatively low, which is related to the fact that the complete spatial information is placed in one channel and the single channel information in another channel. It is a multi-channel synthesis, which is stereo compatible and can be played back with normal stereo decoders. The algorithms used give the listener an illusion of spatial sound by exploiting psychoacoustic brain functions.

SAC compression is a standard of MPEG, it is independent of the audio file format used. So that existing audio devices can play surround sound with Spatial Audio Coding. It is a more flexible method than Joint-Stereo and can also be considered an extension of Binaural Cue Coding (BCC).

Informations:
Englisch: spatial audio coding (MPEG) - SAC
Updated at: 20.04.2008
#Words: 192
Links: audio compression, stereophone (stereo), monophone (mono), channel, information
Translations: DE
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