Configuring MRCPv2 speech recognizer services

Example: Single provider configuration that uses MRCPv2

In the following example, a single provider is configured to use an MRCPv2 connection with a speech recognizer, an alternative to using a Speech to Text service instance. Similarly, the configuration properties are formatted for both single and multiple provider configurations, but they use different root level properties. For example, single tenant provider format requires only providerType while the multiple provider configurations include providerSelectionPolicy and providers at the root level.

```JSON {: codeblock}

{ "stt": { "providerType": "mrcpv2", "config": { "mrcpv2ProfileID": "MRCP #1", "recognizeHeaders": { "Speech-Language": "en-US", "Confidence-Threshold": 0.9 }, "recognizeBody": { "contentType": "text/uri", "body": "builtin:grammar/digits?language=en-us\nbuiltin:grammar/boolean?language=en-us" } }, "bargeInResume": true } }

### Example: Multiple provider configuration that uses MRCPv2 {: #MRCP_recognizer_multiple}

In the following example, one provider is shown in a multiple provider formatted JSON configuration file. Unlike the single provider configuration, the multiple provider configuration has `providerSelectionPolicy` and `providers` at the root level.

```json
{
"stt": {
  "providerSelectionPolicy" : "sequential",
  "providers" : [
      {
        "name" : "mrcp-primary",
        "providerType": "mrcpv2",
        "config": {
          "mrcpv2ProfileID": "MRCP #1",
          "recognizeHeaders": {
            "Speech-Language": "en-US",
            "Confidence-Threshold": 0.9,
          },
          "recognizeBody": {
            "contentType": "text/uri",
            "body": "builtin:grammar/digits?language=en-us\nbuiltin:grammar/boolean?language=en-us"
          }
        },
        "bargeInResume": true
      }
  ]
}
}

|

Changes to Speech to Text configuration variables for MRCPv2

The top-level Voice Gateway configuration for the Speech to Text has equivalent values for when you configure an MRCPv2 speech recognizer.

MRCPv2 Recognizer configuration parameters

There are also configuration parameters that are specific to the mrcpv2 provider configuration.

Grammars

Programming an MRCPv2 recognizer usually implies the use of grammars. The MRCPv2 speech recognizer uses grammars to specify the words and patterns that it listens for. Generally, you can use inline grammars, external grammars, and built-in grammars to specify the grammars to be used for the speech recognition.

{
    "vgwAction": {
        "command": "vgwActSetSTTConfig",
        "parameters": {
            "updateMethod": "mergeOnce",
            "config": {
                "recognizeHeaders": {
                    "No-Input-Timeout": 10000
                },
                "recognizeBody": {
                    "contentType": "application/srgs+xml",
                    "body": "<grammar version=\"1.0\" xml:lang=\"en-US\" root=\"digits\"> <rule id=\"confirmations\"> <one-of> <item> affirmative </item> <item> nah </item> <item> no </item> <item> nope </item> <item> yeah </item> <item> yep </item> <item> yes </item> <item> yup </item> <item> fine </item> <item> negative </item> <item> OK </item> <item> sure </item> </one-of> </rule> </grammar>"
                }
            }
        }
    }
 }

{
    "vgwAction": {
    "command": "vgwActSetSTTConfig",
    "parameters": {
      "updateMethod": "mergeOnce",
      "config": {
        "recognizeBody": {
          "body": ["http://example-grammar-server.com/grammars/basic_grammar.xml", "file://grammars/example_file_system_grammar.xml"],
          "contentType": "text/uri-list"
        }
      }
    }
  }
}

{
    "vgwAction": {
    "command": "vgwActSetSTTConfig",
    "parameters": {
      "updateMethod": "mergeOnce",
      "config": {
        "recognizeBody": {
          "body": ["builtin:grammar/digits?language=en-US;length=9"],
          "contentType": "text/uri-list"
        }
      }
    }
  }
}

Handling Recognizer Results

If recognition completes successfully, the result with the highest confidence is used as the input for the Watson Assistant conversation turn. Additionally, the Voice Gateway state variable vgwSTTResponse is set to the resulting JSON, which includes the list of other alternatives as well as the original response from the server. The following example shows that the original response of the MRCPv2 recognizer is set to the mrcpv2RecognizerResult field of the vgwSTTResponse context state variable.

{
  "vgwSTTResponse": {
    "warnings": "",
    "error": "",
    "mrcpv2RecognizerResult": "<?xml version='1.0'?><result><interpretation grammar=\"https:\/\/raw.githubusercontent.com\/WASdev\/sample.voice.gateway\/54e662f18e67c6935e8c8b815b89b57014a37494\/mrcp\/grammar-samples\/store-hours_query.xml\" confidence=\"0.76\"><input mode=\"speech\">Are you open on Sunday<\/input><instance><SWI_literal>Are you open on Sunday<\/SWI_literal><SWI_grammarName>https:\/\/raw.githubusercontent.com\/WASdev\/sample.voice.gateway\/54e662f18e67c6935e8c8b815b89b57014a37494\/mrcp\/grammar-samples\/store-hours_query.xml<\/SWI_grammarName><SWI_meaning>{SWI_literal:Are you open on Sunday}<\/SWI_meaning><\/instance><\/interpretation><interpretation grammar=\"https:\/\/raw.githubusercontent.com\/WASdev\/sample.voice.gateway\/54e662f18e67c6935e8c8b815b89b57014a37494\/mrcp\/grammar-samples\/store-hours_query.xml\" confidence=\"0.29\"><input mode=\"speech\">Are you open on Monday<\/input><instance><SWI_literal>Are you open on Monday<\/SWI_literal><SWI_grammarName>https:\/\/raw.githubusercontent.com\/WASdev\/sample.voice.gateway\/54e662f18e67c6935e8c8b815b89b57014a37494\/mrcp\/grammar-samples\/store-hours_query.xml<\/SWI_grammarName><SWI_meaning>{SWI_literal:Are you open on Monday}<\/SWI_meaning><\/instance><\/interpretation><\/result>",
    "results": [{
      "final": true,
      "alternatives": [{
        "transcript": "Are you open on Sunday",
        "confidence": "0.76"
      }, {
        "transcript": "Are you open on Monday",
        "confidence": "0.29"
      }]
    }]
  }
}

In unsuccessful recognition results, the Voice Gateway sends the keyword as the user input,vgwMrcpRecognitionUnsuccessful, to inform Watson Assistant that recognition was not successful. In example case, the state variable, vgwMrcpRecognizerResponse, is set to the response of the MRCPv2 recognizer.

{
   "context": {
      "vgwMrcpRecognizerResponse": {
           "headers": {
                "Completion-Cause": "001 no-input-timeout"
            },
            "body": "<body of the recognition result>"
      }
   }

}

The conversation developer can check the response of the MRCPv2 recognizer vgwMrcpRecognizerResponse for insight on what occurred to the recognition request. For a full list of recognition completion causes, you can look into the MRCPv2 RFC.