GSR | CVP | External SRGS Grammar File | Error : Unsupported Grammar Format

Subin Sunderdas

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Sep 6, 2019, 12:16:30 PM9/6/19

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Hi All,

Issue : GSR | External SRGS Grammar file | Error : Unsupported Grammar Format

We have integrated CVP with UniMRCP. We are using GSR for speech transcription and GSS for Synthesized speech. We have developed IVR application which works as expected when we use builtin grammar for voice and DTMF.

However when we try to use external srgs grammar (grxml), we are observing UniMRCP server is throwing Unsupported Grammar Format error.

Findings from UniMRCP log:

In DEFINE-GRAMMAR method, Content-Type is set to text/uri-list instead of application/srgs+xml. From IVR application we are sending grammar type as application/srgs+xml.

UniMRCP Log:

2019-09-05 03:10:31:314452 [INFO] Receive MRCPv2 Data 10.38.244.162:1544 <-> 10.38.244.153:54997 [360 bytes]

MRCP/2.0 358 DEFINE-GRAMMAR 100

Channel-Identifier: a94b600c55e84066@speechrecog

Fetch-Timeout:10000

Cache-Control:max-stale=0,max-age=300

Content-Base:http://10.38.244.134:7000/CVP/Server

Content-Type:text/uri-list

Speech-Language:en-US

Content-Id:fie...@field.grammar

Content-Length: 56

http://10.38.244.134/grammars/unimrcp/UniMRCPVoice.grxml

IVR application assigning proper grammar type:

</prompt>

I have attached UniMRCP log and grammar file for your reference.

grxml.log

UniMRCPVoice.grxml

Doug Rylaarsdam

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Sep 6, 2019, 1:50:50 PM9/6/19

to UniMRCP

The text/uri-list looks okay (that is the payload type of the DEFINE-GRAMMAR request). The server does not support http fetching of grammar files, so that is likely the cause of the 004 grammar-load-failure. Try using an in-line SRGS grammar.

On Friday, September 6, 2019 at 11:16:30 AM UTC-5, Subin Sunderdas wrote:

Hi All,

Issue : GSR | External SRGS Grammar file | Error : Unsupported Grammar Format

We have integrated CVP with UniMRCP. We are using GSR for speech transcription and GSS for Synthesized speech. We have developed IVR application which works as expected when we use builtin grammar for voice and DTMF.

However when we try to use external srgs grammar (grxml), we are observing UniMRCP server is throwing Unsupported Grammar Format error.

Findings from UniMRCP log:

In DEFINE-GRAMMAR method, Content-Type is set to text/uri-list instead of application/srgs+xml. From IVR application we are sending grammar type as application/srgs+xml.

UniMRCP Log:

2019-09-05 03:10:31:314452 [INFO] Receive MRCPv2 Data 10.38.244.162:1544 <-> 10.38.244.153:54997 [360 bytes]
MRCP/2.0 358 DEFINE-GRAMMAR 100
Channel-Identifier: a94b600c55e84066@speechrecog
Fetch-Timeout:10000
Cache-Control:max-stale=0,max-age=300
Content-Base:http://10.38.244.134:7000/CVP/Server
Content-Type:text/uri-list
Speech-Language:en-US

Content-Id:field1@field.grammar

Michael Levy

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Sep 6, 2019, 8:21:25 PM9/6/19

to UniMRCP

Yes, the define-grammar looks correct.

VXML tags get mapped to MRCP commands.

The MRCP define-grammar uses content-type text/uri-list when the body of the define-grammar command is a URI or a list of URIs. This is the case in this example.

The MRCP define-grammar command would specify the content-type application/srgs+xml when the body of the define-grammar command included the text of the grammar. This is typically the case when VXML includes grammars inline (the grammar is specified in the <grammar> tag and not just a src URI).

Arsen Chaloyan

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Sep 10, 2019, 9:23:06 PM9/10/19

to UniMRCP

Although the message flow is correct, fetching grammars via HTTP is not currently supported by the SR plugins.

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