...
The timeline preview player will always mix odd channel to the left side, and even channels to the right side of the players output audio signal. The user therefore does not need to take care about any audio routing options and the stereo mix is generated automatically. Also the user has the possibility to mute channels (compare Mute and Hide Tracks [INT VE 21.3 UG] ) that will be ignored on timeline playback.
...
While the preview is based on 2 channels, the publish phase will haven more options based on the output format. For example, imagine a output into a XDCAMHD file that has 8 audio channels. In this scenario it might make sense to store the mix on channel 1 and 2, but the voice over on channel 3 and 4. This can be done in the transcoder preset (shape tag) configuration. Please refer to https://vidispine.atlassian.net/wiki/pages/createpage.action?spaceKey=ITSFP&title=Publish%20Transcoding%20Preset%20Configuration%20%5BINT%20VE%2021.3%20OG%5D and https://vidispine.atlassian.net/wiki/pages/createpage.action?spaceKey=ITSFP&title=Direct%20Out%20Publish%20Configuration%20%5BINT%20VE%2021.3%20OG%5D Publish Transcoding Preset Configuration [VE 21.3 OG] and Direct Out Publish Configuration [VE 21.3 OG] for an introduction about this configuration.
...