BTW, something for this debate- some of the newer formats like aac/mp4 eliminated the option for 'stereo' completely as far as I know.
Also from
this page titled
Popular MISCONCEPTIONS about mp3-
mp3 192 kbps CBR stereo is the best and optimal quality/filesize option
NOT TRUE! This is simple. Such opinions were spread after many users realized that 128 kbps mp3s were not perfect and tried the existing encoders with higher bit-rates (CBR and VBR). But at that time implementations of VBR and joint stereo algorithms were far from perfect too (especially Xing encoders which still do not shine, but also Fraunhofer VBR -- refer to ff123's evaluation). So this misconception arose, saying that only CBR full stereo at high enough bit-rate can provide good quality.
Now, as we have Lame developed virtually to the edge, with tuned-up ABR and VBR alt-presets and smart joint stereo, there is no good reason to use either CBR or full stereo any more. It's just a waste of bits. Standard VBR alt-preset averages at the bit-rates around 192, and the sound quality is better than CBR 192, and better than any other encoders at similar bitrates. It was proven with numerous listening tests by many (those with better ears than average!) of the members of HydrogenAudio community.
mp3 320 kbps CBR Stereo is the upper limit quality you can get with mp3
Not exactly true. Yes, 320 kbps is the maximum possible bit-rate according to mp3 standard. But Joint Stereo can be effectively utilized also at 320 kbps, thus providing more bits for encoding audio content. If an audio source has low stereo separation, encoding it in full stereo 320 kbps is simply inefficient.
VBR makes mp3 sound awful.
NOT TRUE! A properly designed VBR algorithm can only improve sound quality, not wasting bits for "easy-to-encode" pieces but saving them for "difficult" ones.
The spread of the misconception was probably caused by the older buggy implementations of VBR in FhG encoders, and too imperfect Xing VBR. There is no problem of any kind using VBR with recent Lame encoder, because its VBR algorithms were tuned considerably to handle even "difficult" samples. Please refer to HydrogenAudio mp3 fora for more up-to-date information on VBR alt-presets.
Joint Stereo degrades the stereo image and overall sound quality and kills off "surround" information.
NOT TRUE! The state-of-the-art encoders (Lame, Musepack, PsyTEL AACenc, Ogg-Vorbis) exploit the so called smart joint stereo algorithms, which practically never damage stereo image at higher bit-rates. Please refer to this more technical explanations by the Lame alt-preset developer 'Dibrom' and also to this discussion of safe js.
Even more so with MPC, as Frank Klemm says here. Restricting the mpc encoder to full stereo will actually degrade overall quality.
There can be certain stereo problems with Ogg-Vorbis unless Vorbis lossless stereo-coupling is used (which is in fact a kind of smart joint stereo).
Regarding surround: this is a somewhat contraversial topic. In theory, lossy encoders are not obliged to take care of surround data, because surround stereo systems perform intensive digital sound processing (DSP) to make the sound "surround", and lossy compression is not intended to be used in any DSP. However, in practice, a proper joint stereo implementation is usually capable of preserving surround info.
Please refer to this discussion, and this discussion of surround in musepack.
NOTE: At lower bit-rates, all encoders use a more "aggressive" joint stereo modes. If you plan to listen to encoded files on a surround sound system, then you might need a higher bitrate preset: --alt-preset extreme or insane for mp3 (these presets make use of "safe joint stereo" switch); --quality 6 (--xtreme) or higher for musepack.
Those presets activate less agressive joint stereo modes, preserving the signal components that are not audible on an ordinary stereo system, but might be audible on a surround system.