auto lip sync : how to swap between mouth libraries on one track

how does one swap between different mouth libraries when auto lip-syncing to a track? e.g. in one track a character needs both ‘happy’ and ‘sad’ mouth phonemes, or both a front and 3/4 view. can one map to a selection of the track for one set of mouths, and then select a different part of the track to map a different set? or does the whole track get read with only one library, necessitating another method, like, i don’t know, mapping one line with the different phoneme libraries to different layers and then cutting between them? or chopping up the audio track isolating the sections that will use different libraries?

It’s possible to rig characters for one orientation or for
multiple orientations (full turnaround rig).

Each method has its benefits and drawbacks. For example
a full turnaround rig would have one mouth layer only,
however there would be more drawings (for all the mouth
shapes multiplied by the orientations). For separate orientation
rigs the structures must match and you would have multiple
mouth layers (one per orientation) each mapped to the same
audio file. Depending which way the character is facing you
enable/disable or show/hide the necessary view and do
any drawing replacement from the library in the appropriate
orientation mouth layer.

More info is available here: