| Stereo downmixes (or fold-downs)
Left total/Right total (Lt/Rt)
Lt/Rt is a downmix suitable for decoding with a Dolby
Lt = L + -3dBC - -3dB(Ls + Rs)
Rt = R + -3dBC + -3dB(Ls + Rs)
(Ls,Rs 90-degree phase shifted)
Left only/Right only (Lo/Ro)
Lo/Ro is a downmix suitable for stereo playback
Lo = L + -3dBC + attLs
Ro = R + -3dBC + attRs
(att=-3dB or -6dB or -9dB or 0)
5.1 downmix
5.1 to LR Ls to L drop 6 db (.5) , Rs to R drop 6 db (.5), C to L & R drop 3db (.707) , lose the sub.
or
Lt = FL + s*SL + c*C
Rt = FR + s*SR + c*C
where s (=surround mix) is usually something between 0.5 and 1
and c (=center mix) is usually 0.7. This would be a "normal" stereo downmix.
or
Lt = FL + s*(SL+SR) + c*C
Rt = FR - s*(SL+SR) + c*C // 180° phase shift SL+SR
with s=0.5 and c=0.7.
cheers
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