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PocketSphinx Plugin

Administrator Guide


Revision: 5

Distribution: Debian / Ubuntu

Created: February 3, 2017

Last updated: August 30, 2017

Author: Arsen Chaloyan


Table of Contents

1 Overview.. 3

1.1 Applicable Versions. 3

1.2 Supported Distributions. 3

1.3 Authentication. 3

2 Installing Deb Packages Using Apt-Get 4

2.1 Repository Configuration. 4

2.2 GnuPG Key. 4

2.3 Repository Update. 4

2.4 PocketSphinx Plugin Installation. 4

3 Installing Deb Packages Manually. 6

3.1 Package List 6

3.2 Package Installation Order 7

4 Obtaining License. 8

4.1 License Type. 8

4.2 Node Information. 8

4.3 License Installation. 8

5 Configuring Server and Plugin. 9

5.1 Plugin Factory. 9

5.2 Logger 9

5.3 PocketSphinx. 9

6 Validating Setup. 10

6.1 Launching Server 10

6.2 Launching Client 10



1       Overview

This guide describes how to obtain and install binary packages for the PocketSphinx plugin to the UniMRCP server on Debian-based Linux distributions. The document is intended for system administrators and developers.

1.1      Applicable Versions

Instructions provided in this guide are applicable to the following versions.


UniMRCP 1.5.0 and above

UniMRCP PocketSphinx Plugin 1.0.0 and above

1.2      Supported Distributions

UniMRCP binary packages are currently available only for x86_64 (64-bit) architecture.


Operating System



Ubuntu 14.04 LTS (trusty)



Ubuntu 16.04 LTS (xenial)




Note: packages for other distributions can be made available upon request. For more information, contact services@unimrcp.org.

1.3      Authentication

UniMRCP binary packages are available to authenticated users only. In order to register a free account with UniMRCP, please visit the following page.




Note: a new account needs to be verified and activated prior further proceeding.

2       Installing Deb Packages Using Apt-Get

Using the APT package handling utility (apt-get) is recommended for installation of UniMRCP binary packages.

2.1      Repository Configuration

The content of a typical configuration file of the APT repository, to be placed in /etc/apt/sources.list.d/unimrcp.list, is provided below.


deb [arch=amd64] https://username:password@unimrcp.org/repo/apt/ distr main


The username and password fields included in the HTTPS URI must be replaced with the corresponding account credentials.

The distr field must be replaced with the corresponding distribution code name such as trusty, xenial, etc.

2.2      GnuPG Key

For verification of binary packages, UniMRCP provides a public GnuPG key, which can be retrieved and installed as follows.


wget -O - https://unimrcp.org/keys/unimrcp-gpg-key.public | sudo apt-key add -


2.3      Repository Update

In order to check for updates and apply the changes in the APT configuration, use the following command.


sudo apt-get update


2.4      PocketSphinx Plugin Installation

In order to install the PocketSphinx plugin package, including all the dependencies, use the following command.


sudo apt-get install unimrcp-pocketsphinx


As a result, apt-get will check and prompt to download all the required packages by installing them in the directory /opt/unimrcp.


In order to install the en-US model package for PocketSphinx, use the following command.


sudo apt-get install unimrcp-pocketsphinx-model-en-us


Note: this package provides acoustic data files required for the PocketSphinx engine to perform recognition for the en-US language. Packages for other languages can be made available upon request.


In order to install the additional data files for the sample client application umc, the following command can be used.


sudo apt-get install umc-addons


Note: this package is optional and provides additional data which can be used for validation of basic setup.

3       Installing Deb Packages Manually

UniMRCP deb packages can be installed manually using the dpkg utility. Note, however, that the system administrator should take care of package dependencies and install all the packages in appropriate order.


The deb packages have the following naming convention:





         packagename is the name of a package

         universion is the UniMRCP version

         distr is the distribution code name (trusty, xenial, )

         arch is the architecture (amd64, i386, all, )

3.1      Package List

The following is a list of UniMRCP deb packages required for the installation of PocketSphinx plugin.


Package Name



PocketSphinx plugin to the server.


PocketSphinx en-US language files.


Sample en-US data files used with umc. [Optional]


Node information retrieval tool, required for license deployment.


Shared library and application of the server.


Shared libraries and sample applications of the client. [Optional]


Set of demo plugins to the server. [Optional]


Data common for the client and the server.


UniMRCP edition of the Apache Portable Runtime (APR) library.


UniMRCP edition of the Apache Portable Runtime Utility (APR-Util) library.


UniMRCP edition of the Sofia SIP library.

3.2      Package Installation Order

Packages for APR, APR-Util and Sofia-SIP libraries must be installed first.


sudo dpkg --install uniapr_$aprversion-$distr_$arch.deb

sudo dpkg --install uniapr-util_$apuversion-$distr_$arch.deb

sudo dpkg --install unisofia-sip_$sofiaversion-$distr_$arch.deb


Then, a package containing common data for the client and the server, and a package for the server should follow.


sudo dpkg --install unimrcp-common_$universion-$distr_$arch.deb

sudo dpkg --install unimrcp-server_$universion-$distr_$arch.deb


Next, a package containing the utility tool unilicnodegen, required for license deployment.


sudo dpkg --install unilicnodegen_$toolversion-$distr_$arch.deb


Next, a package containing the PocketSphinx plugin should follow.


sudo dpkg --install unimrcp-pocketsphinx_$universion-$distr_$arch.deb


Finally, one or more packages corresponding to a particular language should follow.


sudo dpkg --install unimrcp-pocketsphinx-model-en-us_$universion-$distr_all.deb


4       Obtaining License

The PocketSphinx plugin to the UniMRCP server is a commercial product, which requires a license file to be installed.

4.1      License Type

The following license types are available:



         Test and Development

4.2      Node Information

The license files are bound to a node the product is installed on. In order to obtain a license, the corresponding node information needs to be retrieved and submitted for generation of a license file.


Use the installed tool unilicnodegen to retrieve the node information.


sudo /opt/unimrcp/bin/unilicnodegen


As a result, a text file uninode.info will be saved in the current directory. Submit the file uninode.info for license generation to services@unimrcp.org by mentioning the product name in the subject.

4.3      License Installation

The license file needs to be placed into the directory /opt/unimrcp/data.


sudo cp umspocketsphinx_*.lic /opt/unimrcp/data


5       Configuring Server and Plugin

5.1      Plugin Factory

In order to load the PocketSphinx plugin into the UniMRCP server, open the file unimrcpserver.xml, located in the directory /opt/unimrcp/conf, and add the following entry under the XML element <plugin-factory>. Disable other recognition plugins, if available. The remaining demo plugins might also be disabled, if not installed.


<!-- Factory of plugins (MRCP engines) -->


<engine id="Demo-Synth-1" name="demosynth" enable="true"/>

<engine id="Demo-Recog-1" name="demorecog" enable="false"/>

<engine id="Demo-Verifier-1" name="demoverifier" enable="true"/>

<engine id="Recorder-1" name="mrcprecorder" enable="true"/>

<engine id="PS-Recog-1" name="umspocketsphinx" enable="true"/>



5.2      Logger

In order to enable log output from the plugin and set filtering rules, open the configuration file logger.xml, located in the directory /opt/unimrcp/conf, and add the following entry under the element <sources>.


<source name="PS" priority="INFO" masking="NONE"/>


5.3      PocketSphinx

The configuration file of the plugin is located in /opt/unimrcp/conf/umspocketsphinx.xml and the data files are in the directory /opt/unimrcp/data/pocketsphinx.


Refer to the Usage Guide for more information.


6       Validating Setup

Validate your setup by using the sample UniMRCP client and server applications on the same host. The default configuration and data files should be sufficient for a basic test.

6.1      Launching Server

Launch the UniMRCP server application.


cd /opt/unimrcp/bin

sudo ./unimrcpserver


In the server log output, check whether the plugin is normally loaded.


[INFO] Load Plugin [PS-Recog-1] [/opt/unimrcp/plugin/umspocketsphinx.so]


Next, check for the license information.


[NOTICE] UniMRCP PocketSphinx License


-product name: umspocketsphinx

-product version: 1.0.0

-license owner: Name

-license type: trial

-issue date: 2017-01-28

-exp date: 2017-02-27

-channel count: 2

-feature set: 0


6.2      Launching Client

Note: the optional package umc-addons must be installed for this test to work.


Launch the sample UniMRCP client application umc.


cd /opt/unimrcp/bin



Run a typical speech recognition scenario by issuing the command run ps1 from the console of the umc client application.


run ps1


This command sends a RECOGNIZE request to the server and then starts streaming a sample audio input file callsteve.pcm to recognize.


Check for the NLSML results to be returned as expected.


<?xml version="1.0"?>


<interpretation grammar="request1@form-level" confidence="1.00">

<instance>call steve</instance>

<input mode="speech">call steve</input>




Visually inspect the log output for any possible warnings or errors.


Note that utterances are stored in the var directory, if the corresponding parameter is enabled in the configuration file umspocketsphinx.xml and/or requested by the client.