Intensity stereo

Intensity stereo coding is a method that achieves a saving in bitrate by replacing the left and the right signal by a single representing signal plus directional information. This replacement is psychoacoustically justified in the higher frequency range since the human auditory system is insensitive to the signal phase at frequencies above approximately 20kHz.

Intensity stereo is by definition a lossy coding method thus it is primarily useful at low bitrates. It does not keep the phase information of the signal. for coding at higher bitrates m/s-stereo or stereo -coding should be used.