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Streaming Media Properties (MRCPV1)

Reference Number: AA-01107 Views: 1241 0 Rating/ Voters

Streaming Media Properties

The following parameters are part of the MRCPv1 specification, and can be controlled via the mrcp.config file, located in the config directory of the MRCPv1 installation folder. By default, this location is C:\Program Files\Lumenvox\MRCPServer\config\

They may also be set with the appropriate header as part of a RECOGNITION or SET-PARAMS method. Refer to the MRCPv1 RFC, section 8.4, for more information about changing the parameters using recognizer headers.

See Configuring Parameters for general information about changing various MRCPv1 parameters.

dtmf_payload_type

This parameter may be used to customize the DTMF RTP payload type. Different vendors have used their own DTMF payload types. We allow this to be configurable.

Default: 96

nbest_length

When the recognizer matches audio with a grammar, it may come up with more than one alternative match because of confidence levels in certain words or conversation paths. By default, the Speech Engine will only return the best match above the confidence threshold. The nbest_length parameter determines how many different results to return. All alternatives must still be above the confidence-threshold. A value greater than one does not guarantee that the recognizer will send the requested number of alternatives. The minimum value for this field is 1.

Default: 1

confidence_thrsld

When a recognition resource recognizes an utterance with some portion of the grammar, it associates a confidence level with that conclusion. The confidence-threshold parameter tells the recognizer resource what confidence level should be considered a successful match. This is an integer from 0-100 indicating the recognizer's confidence in the recognition. If the recognizer determines that its confidence in all its recognition results is less than the confidence threshold, then it returns no-match as the recognition result.

Default: 20

sensitivity_lvl

Controls the sensitivity level for barge-in. It is set on a scale of 0 to 100; the higher the value, the more easily the system will barge-in. For a similar value, see snr_sensitivity in our vendor-specific Recognizer Properties.

Default: 50

speed_vs_accuracy

At this time, this parameter is unused.

speech_incomplete_timeout

At this time, this parameter is unused.

no_input_timeout

After recognition has started, if there is no speech detected for a certain period of time, the recognizer will send a RECOGNITION-COMPLETE event to the client and terminate the recognition operation. The no-input-timeout parameter controls the length of this time period. The value is in milliseconds.

Default: 20000

dtmf_term_char

This parameter specifies the terminating DTMF character for DTMF input recognition. When the specified character is received, the system will immediately stop waiting for DTMF input.

Default: #

dtmf_termination_timeout

The terminating timeout to use when recognizing DTMF input. When no DTMF input has been detected for the length of time set by this parameter, the system will stop waiting for DTMF input. The value is in milliseconds. The value for this field ranges from 0 to MAXTIMEOUT, where MAXTIMEOUT is platform specific. Refer to the VoiceXML 2.0 specification, Appendix D for detailed information.

Default: 10000

dtmf_inter_digit_timeout

This parameter specifies the inter-digit timeout value to use when recognizing DTMF input. The value is in milliseconds. The value for this field ranges from 0 to MAXTIMEOUT, where MAXTIMEOUT is platform specific. Refer to the VoiceXML 2.0 specification, Appendix D for detailed information.

Default: 5000

recognizer_start_timers

If set, the recognizer will not start the timers until the client sends a RECOGNITION-START-TIMERS method to the recognizer.

Default: false

recognition_timeout

After recognition has started and there is no match for a certain period of time, the recognizer can send a RECOGNITION-COMPLETE event to the client and terminate the recognition operation. The recognition-timeout parameter field sets this timeout value. The value is in milliseconds. The value for this field ranges from 0 to MAXTIMEOUT, where MAXTIMEOUT is platform specific.

Default: 10000

save_waveform

The MRCP server can save the audio stream that was used for a recognition if the client sets this parameter to true. The server records the audio and makes it available to the client in the form of a URI returned in the waveform-uri header field in the RECOGNITION-COMPLETE event. If there is an error in recording the stream, the recognizer returns a blank waveform-uri header field.

Default: false

waveform_url_location

This parameter is used in conjunction with the save-waveform parameter. This tells the MRCP server where to put the recorded audio-stream. It is only used if the save_waveform parameter is set to true.

Default: "" (empty string)