The "Audio" tab permits to manage the following audio formats for the tracks of an asset:
Audio tab
L - Left mono 1
R - Right mono 1
B - Bi-mono 1 + 1
S - Stereo 2
C - Dolby AC3 5.1 (Dolby Digital)
E - Dolby 5.1 + 1 + 1
U - Unknown ?
N - No audio 0
For instance:
Channel 1-2 - Stereo
Channel 3-4 - Stereo (in the same language than channel 1&2)
Channel 5-6 - Left Mono (in the same language than channel 1&2)
Channel 7-8 - Right Mono (in the same language than channel 1&2).