Note that many albums (especially live shows) seem to have this type of surround channel information; I believe it's either intentional or a side-effect of the way 2.1 decoding interprets the audio.
My problem with the encoding quality is not so much the preservation of the surround channel, but the fact that it can contain very annoying artifacts if not properly encoded. Dolby surround or mere side-effect, I'd prefer not to hear distortion behind my head.
The funny thing is that --ms 15 seemed to provide better quality for one particular portion of the sample than --ms 0. There's a patch at 0.4s to 0.7s that sounds "rougher" on --ms 0 than --ms 15. Possibly just coincidence.
--ms 0 disables Mid/Side coding. This reduces significantlyquality for signal with high channel correlation.This effect is called stereo unmasking. First mentioned in 1953.A related effect is the "cocktail party effect".
Maybe someone should add this to the recommend MPC command lines. CiTay?
please correct me if i am wrong but, just because you dont have a "surround" recording doesnt necessarily mean that your recordings dont contain any surround information.