TMPGEnc sound settings?

[disastermaster]

Hi, I`ve been playing with the settings on TMPGEnc (trying to get longer mpegs on to xvcd) and I was wondering what the different,audio/channel mode settings did.
What is the difference between stereo, joint-stereo and dual -channel and what difference do they make to file size/quality

[DrP]

Stereo = two separate audio channels one left, one right, no attempt to find common info between the channels to save bits. If you do VBR audio (not for mpegs of course), one channel is able to steal bits from another channel if the other channel doesnt require all the bits it has been allocated to encode the stream

Joint Stereo = Left and right are compared for common info, audio is encoded as (most commonly) side + middle. Allows better allocation of bits for high frequency as most stereo audio has lots of common audio in both channels. Can result in fluttering effects if there is too much separation between left and right.

Mono = i think that says it all

Dual = two competely separate mono audio channels. Usually multilanguage support etc.

All in all most people recommend using JS for rates of 192 and below and stereo for rates over 192 (ie 224) for quality of audio.

Since mpegs have CBR audio, the size of any stereo audio track will be the same, just the quality changes (assuming same bitrate).