Raspberry Pi, Pocketsphinx STT and Jasper Good Stuff...


  • Part of this documentation has been taken from the Jasper website.
  • Also take a look at Wolf Paulus’ Journal where you can find a tutorial for installing and run your local STT with customized Language Model.


Before starting you may want to install checkinstall:

$ sudo apt-get install checkinstall

Checkinstall create a deb package that can be easily installed and removed using dpkg or apt-get.

It might happen that checkinstall fail with some recursive thing messages. In that case just go with the normal make install and than try again with checkinstall.

Update the system

Before compiling and installing all the necessary packages let’s update the system with the following commands:

$ sudo apt-get update
$ sudo apt-get dist-upgrade
$ apt-get install rpi-update
$ sudo rpi-update

Take a look at your sound card information

$ cat /proc/asound/cards

it will returns something along the line:

0 [ALSA ]: bcm2835 - bcm2835 ALSA
bcm2835 ALSA
1 [AK5370 ]: USB-Audio - AK5370
AKM AK5370 at usb-bcm2708_usb-1.2, full speed

...showing that the microphone is visible and its usb extension.

Installing build tools and required libraries

$ sudo apt-get update
$ sudo apt-get upgrade
$ sudo apt-get install bison
$ sudo apt-get install libasound2-dev
$ sudo apt-get install swig
$ sudo apt-get install python-dev
$ sudo apt-get install mplayer

Recording Test

The current recording settings can be looked at with:

$ amixer -c 1 sget 'Mic',0

Simple mixer control 'Mic',0
Capabilities: cvolume cvolume-joined cswitch cswitch-joined penum
Capture channels: Mono
Limits: Capture 0 - 78

Mono: Capture 68 [87%] [10.00dB] [on]

alsamixer can be used to increase the capture levels. After an increase, it looks like this:

$ alsamixer -c 1

Mono: Capture 68 [87%] [10.00dB] [on]


For the version 0.8v of sphinxbase and pocketsphinx we need to recompile the C source files cause of some bugs. This process is important if you are going to use a Python Virtual Environment for Jasper.

Delete the python/sphinxbase.c in sphinxbase folder and python/pocketsphinx.c in pocketsphinx folder, these files will be generated again after you execute make from their respective folders.

Install cython if you don’t have it already, it is required in order to recompile the c files.

$ sudo apt-get install cython

Building Sphinxbase


Do not use 5prealpha with Jasper if you do not want to change Jasper source code

$ wget http://downloads.sourceforge.net/project/cmusphinx/sphinxbase/0.8/sphinxbase-0.8.tar.gz
$ tar -zxvf sphinxbase-0.8.tar.gz
$ cd ~/sphinxbase-0.8/
$ ./configure --enable-fixed
$ make clean all
$ sudo make install

Building PocketSphinx

$ wget http://downloads.sourceforge.net/project/cmusphinx/pocketsphinx/0.8/pocketsphinx-0.8.tar.gz
$ tar -zxvf pocketsphinx-0.8.tar.gz
$ cd ~/pocketsphinx-0.8/
$ ./configure
$ make clean all
$ sudo make install

Installing CMUCLMTK

Begin by installing some dependencies:

$ sudo apt-get install subversion autoconf libtool automake gfortran g++ --yes

Next, move into your home (or Jasper) directory to check out and install CMUCLMTK:

$ svn co https://svn.code.sf.net/p/cmusphinx/code/trunk/cmuclmtk/
$ cd cmuclmtk/
$ ./autogen.sh && make && sudo make install

Installing Phonetisaurus, m2m-aligner and MITLM


I had some problems compiling Phonetisaurus from Raspberry Pi 2 and this is how I resolved.

Check the version of your g++ compiler with the command:

$ g++ -v

Using built-in specs.
gcc version 4.6.3 (Debian 4.6.3-14+rpi1)

The gcc version 4.6.3 provide experimental support for C++0x (https://gcc.gnu.org/gcc-4.6/cxx0x_status.html) but in my case the build of Phonetisaurus fail.

The solution is to use the compiler c++03 in this situation.

If you have g++ 4.7 you still might have this problem and you should try with the compiler c++11 instead.

To change the compiler before the make just give this command:

// for g++-4.6
$ CPPFLAGS="-std=c++03" make

// for g++-4.7
$ CPPFLAGS="-std=c++11" make

reference: https://gcc.gnu.org/projects/cxx0x.html

To use the Pocketsphinx STT engine, you also need to install MIT Language Modeling Toolkit, m2m-aligner and Phonetisaurus (and thus OpenFST).:

$ wget http://distfiles.macports.org/openfst/openfst-1.3.3.tar.gz
$ wget https://mitlm.googlecode.com/files/mitlm-0.4.1.tar.gz
$ wget https://m2m-aligner.googlecode.com/files/m2m-aligner-1.2.tar.gz
$ wget https://phonetisaurus.googlecode.com/files/is2013-conversion.tgz (phonetisaurus)

Untar the downloads:

$ tar -xvf m2m-aligner-1.2.tar.gz
$ tar -xvf openfst-1.3.3.tar.gz
$ tar -xvf phonetisaurus-0.7.8.tgz
$ tar -xvf mitlm-0.4.1.tar.gz

Build OpenFST:

$ cd openfst-1.3.3/
$ ./configure --enable-compact-fsts --enable-const-fsts --enable-far --enable-lookahead-fsts --enable-pdt
$ sudo make install # come back after a really long time

Build M2M:

$ cd m2m-aligner-1.2/
$ make


$ cd mitlm-0.4.1/
$ ./configure
$ sudo make install

Build Phonetisaurus:

$ cd phonetisaurus-0.7.8/
$ cd src

// for 0.7.8
$ sudo make

// for 0.7.8a using g++-4.6
$ sudo CPPFLAGS="-std=c++03" make

// for 0.7.8a using g++-4.7
$ sudo CPPFLAGS="-std=c++11" make

Move some of the compiled files:

$ sudo cp ~/m2m-aligner-1.2/m2m-aligner /usr/local/bin/m2m-aligner
$ sudo cp ~/phonetisaurus-0.7.8/phonetisaurus-g2p /usr/local/bin/phonetisaurus-g2p

Building the Phonetisaurus FST model

$ wget https://www.dropbox.com/s/kfht75czdwucni1/g014b2b.tgz
$ tar -xvf g014b2b.tgz

Build Phonetisaurus model:

$ cd g014b2b/
$ ./compile-fst.sh

[optional] Finally, rename the following folder for convenience:

$ mv ~/g014b2b ~/phonetisaurus


Follow the configuration instructions on the Jasper website http://jasperproject.github.io/documentation/configuration/ to set your sphinx STT service.

Done! Enjoy!