What's the Difference between Stereo, Joint-Stereo and Dual-Channel?

Joint-Stereo - This method of encoding combines duplicate (or "perceptually similar") information from the Right and Left channels in an effort to most efficiently compress the file. This way the duplicate information is only encoded *once* instead of twice (one time for each channel) and allows for more bits to be allocated to the other non-duplicate information. The problem with Joint-Stereo is that it occasionally produces a flanging or "swooshing" effect to the resulting MP3, which can be remedied by re-encoding with either Stereo or Dual-Channel. Hypothetically Joint-Stereo should produce the best sounding MP3s (because it so efficiently utilizes it's bits while encoding). The reality however is that Joint-Stereo all too frequently produces inferior sounding MP3s. Dual-Channel - Two independent channels. This method keeps the Right and Left channel information completely separate. The downside is that if there is very little information on the Left channel, there is some "waste" ...  more