There are two tracks on 35mm stereo optical prints, referred to as Lt –Rt, on which are matrixed four channels of information. The 4:2 encoding is done during the print mastering, with the 2:4 decoding occurring at playback (at the theater). All of the stereo optical prints: Dolby Stereo (A-Type), Dolby-SR, DTS Stereo, and Ultra-Stereo occupy the same area as standard mono optical prints. The degree of mono compatibility is mix-dependent.
