Properties in MRCP/VXML/API
One difficult thing about developing applications using standards such as MRCP and VXML is that the names of similar parameters are often slightly different between the standards. This is particularly important when tuning voice activity detection parameters.
The following table presents a comparison of VAD properties in MRCP and their equivalent name in VXML and the LumenVox API (used with LV_SRE_StreamSetParameter and LVSpeechPort::StreamSetParameter).
In some cases the parameters do not have direct matches, so the exact mappings may differ depending on how a platform interprets the meaning of one specification or the other. Thus you should consider this table an informational guide rather than as an official interpretation of the standards.
| MRCP | VXML | API |
| Sensitivity-Level 1 | sensitivity 1 | STREAM_PARM_VAD_VOLUME_SENSITIVITY |
| Speech-Complete-Timeout | completetimeout | STREAM_PARM_VAD_EOS_DELAY |
| Speech-Incomplete-Timeout 2 | incompletetimeout 2 | Partially supported by LumenVox 2 |
| com.lumenvox.end-of-speech-timeout | N/A | STREAM_PARM_END_OF_SPEECH_TIMEOUT |
| No-Input-Timeout | timeout | STREAM_PARM_BARGE_IN_TIMEOUT |
| Confidence-Threshold | confidencelevel | N/A (handled by application) |
| Speed-Vs-Accuracy | speedvsaccuracy | N/A |
| N-Best-List-Length | maxnbest | PROP_EX_MAX_NBEST_RETURNED |
| Recognition-Timeout | maxspeechtimeout | N/A |
| Waveform-URL | N/A | N/A |
| DTMF-Interdigit-Timeout | interdigittimeout | N/A |
| DTMF-Term-Timeout | termtimeout | N/A |
| DTMF-Term-Char | termchar | N/A |
1 Note that the sensitivity-level (sensitivity in VXML) works different with MRCP/VXML than in our API. In our API, setting this value higher makes it less sensitive to barge-in. MRCP and VXML are the opposite.
2 As of LumenVox versions 12.0, users can now elect to use the speech-incomplete-timeout value by enabling the 'use_speech_incomplete' option in the media_server.conf settings file. If enabled, the greater of speech-complete-timeout and speech-incomplete-timeout will be used.