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Building PocketSphinxAndroidDemo (from CMUSphinx project)

This is done with CMUSphinx 0.7 (so sphinxbase 0.7 and pocketsphinx 0.7). The files are archived at the end of the article. The process also require access to a linux machine and the Eclipse IDE.

  1. Download Sphinx base and pocket sphinx (
  2. Create a directory somewhere, untar both to ./sphinxbase and ./pocketsphinx (lose the -0.x version suffix)
  3. For each of the two, do the usual ./ ./configure, make, make install (make install require root)
  4. Check ./pocketsphinx/swig has in it. If not, do a make in that directory
  5. Download the PocketSpinxAndroiDemo
  6. untar it to the same directory created in 2
  7. cp -r ./pocketsphinx/swig/edu ./PocketSphinxAndroidDemo/jni/
  8. cd ./PocketSphinxAndroidDemo/jni/
  9. Update SPHINX_PATH to the directory created in 2
  10. Open, edit LOCAL_STATIC_LIBRARIES from whatever it was before to “pocketsphinx sphinxlm sphinxfeat sphinxfe sphinxutil” (without qoutes)
  11. Install Android NDK (
  12. stay in the jni directory, do a ndk-build (see the ndk link about for instructions on building if it is not clear)

Now we are ready to open this in Eclipse

  1. Open eclipse and import the project, ignore any build warnings/errors
  2. Untick Project -> Build Automatically (This is personal choice, since the JNI build process is heavy I dont like it building all the time)
  3. Project -> Properties -> Builders
  4. Select SWIG -> Edit -> for Working Directory, select Browse Workspace and pick the jni directory, In the Refresh tab, select The folder containing the selected resource, in Build Options, untick Specify working set of relevant resources (This option may be hidden in the dialog, if you dont see it, maximize the Configuration window).
  5. Select NDK build -> Edit -> Set the correct location for ndk-build, select the correct Working directory (Browse workspace and then select the jni directory). In the Refresh tab, select The project containing the selected resource, in Build Options, untick Specify working set of relevant resources (This option may be hidden in the dialog, if you dont see it, maximize the Configuration window).
  6. Project -> Build Project. If you see any errors, check that step 4 and 5 are carried out correctly. The project should build without error. A console may appear with red texts, just confirm that they are warning messages from building the c code and you should be ok

We should now have a built Android application ready for testing

  1. In the emulator (or phone), create under primary storage (whatever is returned by the getExternalStorageDirectory). For example if you have a sdcard this would be /mnt/sdcard
  2. If using the emulator, call adb shell from a console window, and use mkdir command for the step below (to create directories on the emulator)
  3. Create directory structure: Android/edu.cmu.pocketsphinx/hmm/en_US/hub4wsj_sc_8k, Android/edu/edu.cmu.pocketsphinx/lm/en_US/
  4. Copy pocketsphinx/model/hmm/en_US/hub4wsj_sc_8k/* into the emulator/phone
  5. Copy pocketsphinx/model/lm/en_US/* into emulator/phone
  6. In eclipse, open the file, look for c.setString(“-lm”
  7. Make sure the files loaded in the code around step 6 exists (especially the .dict file may have a different name)
  8. Now we can run the application!

If the app crashes for any reason, go to sdcard/Android/edu.cmu.pocketsphinx and there should be a log file (pocketsphinx.log) from the native library.

Misc thought

  • On my machine (OpenSuSE 11.3) the swig directory was empty after make. Go into swig directory and call make, the errors will be displayed (for me it was because I didn’t have swig installed)
  • By default make install installs to /usr/local/lib which can cause problems on some systems. If you get errors with any of the sphinx stuff saying some library is not found, use the ldd and strace commands to see where they are looking for the libs, and symlink them. Alternatively supply another install location to make install
  • While working in eclipse, if you see any errors along the lines of “Refresh scope invalid”, check step 4 and 5 are carried out from the Eclipse section above.

Files required **Before downloading these archives, try using the latest build from the official website first**:

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