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Reference Number: AA-01850 Views: 11449 0 Rating/ Voters

Returns the number of text-to-speech visemes available in the active synthesis result. 

Visemes represent facial expressions related to the pronunciation of certain phonemes.  This information can be used to align visual cues to audio playback.  This may be useful in applications such as lip-syncing. When viseme generation is enabled, these markers will be generated whenever synthesis is performed. For each viseme, there will be an offset (in bytes) within the audio buffer along with a name for each.

Please refer to the phoneme tables associated with the TTS language you are using to look up the viseme that corresponds with each phoneme produced during synthesis.

This functionality was added in LumenVox version 11.3.100 (August 2013)


  • LV_TTS_RETURN_CODE GetVisemesCount(int *return_count)




Memory location of an integer variable into which the number of visemes is to be copied.

Return Values



No errors.


The TTS client handle is invalid (either Initialize has not been called or Destroy has already been called).


An exception occurred while processing the request.



If results are not available yet, the value returned in return_count will be zero even if the method returns LV_SUCCESS.

Also note that visemes will only be generated if viseme generation is enabled,