TTS engine properties SpeedNorm and VolumeNorm for SAPI 4 inconsistent
Last reviewed: 5/12/2003
PRB Article ID: P050302
The information in this article applies to:
Setting a SAPI 4 TTS engine speed and volume using the SpeedNorm and VolumeNorm properties results in inconsistent settings.
SAPI 4 specification allows for large range (DWORD) of values for the vendor to support scaling speed and volume of synthesis playback. The excessive range was addressed in the SAPI 5 specification with smaller ranges. The ChantTTS component provides a SpeedNorm and VolumeNorm property to be able to map SAPI 4 ranges to the SAPI 5 ranges so an application can use the normalized property and not have to check whether a TTS engine (i.e., voice) is SAPI 4 or SAPI 5.
SAPI 4 doesn't always set the value exactly as requested, however, the mapping mechanism has been updated to ensure the requested range is correct in all situations.
Fixed in SpeechKit 4 build 126.96.36.199.
Component Formats Impacted