WikiPedia: Joint Stereo
http://en.wikipedia.org/wiki/Joint_(audio_engineering)
Az MP3 kódolásnál van egy opció, hogy stereo-ba, vagy joint stereoba tömörítsen.
Lame USAGE:
http://www.xmixahlx.com/oldsites/xmixahlxaudio/files/lameusage.txt
JOINT STEREO is the default mode for stereo files with fixed bitrates of 128 kbps or less. At higher fixed bitrates, the default is stereo.
For VBR encoding, jstereo is the default for VBR_q >4, and stereo is the default for VBR_q <=4. You can override all of these defaults by specifing the mode on the command line.
jstereo means the encoder can use (on a frame by frame bases) either regular stereo (just encode left and right channels independently) or mid/side stereo. In mid/side stereo, the mid (L+R) and side (L-R) channels are encoded, and more bits are allocated to the mid channel than the side channel . This will effectively increase the bandwidth if the signal does not have too much stereo separation .