Getting Started: Building for Android

1. Requirements
2. Build Preparation
3. Building PJSIP
   1. Building for other architectures
   2. Notes
4. Video Support
   1. Features
   2. Requirements
   3. Configuring
   4. Adding Video Capture Device to Your Application
   5. Using Video API
   6. Video capture orientation support
5. OpenSSL Support
6. Trying our sample application and creating your own
   1. Setting up the target device
   2. Building and running pjsua2 sample application
   3. Creating your own application
   4. Pjsua sample application with telnet interface
7. Important Issue(s) when Developing Android Apps
   1. Unable to Make or Receive Call (Problem with sending and receiving large (INVITE) requests over TCP)
   2. Garbage Collector May Crash Your App (Pjsua2 API)
   3. OpenSLES audio device deadlock upon shutdown
   4. Bad audio recording quality on some devices
   5. UnsatisfiedLinkError exception with "Native method not found: org.pjsip.pjsua2.pjsua2JNI.swig_module_init" message
   6. A review of Android audio output latency
8. Other Android projects

Requirements

• Besides the ​Android SDK, you will also need the ​Android NDK.
• Optional if you want to build and and run the sample applications (i.e: pjsua2 and pjsua):
  • ​SWIG
  • ​Android Studio

Build Preparation

1. Get the source code from repository, if you haven't already.
2. Set your config_site.h to the following:

   /* Activate Android specific settings in the 'config_site_sample.h' */
   #define PJ_CONFIG_ANDROID 1
   #include <pj/config_site_sample.h>
   

Building PJSIP

Just run:

$ cd /path/to/your/pjsip/dir
$ export ANDROID_NDK_ROOT=/path_to_android_ndk_dir 
$ ./configure-android
$ make dep && make clean && make

Tips: On MinGW32/MSys, use absolute path format D:/path/to/android/ndk instead of /D/path/to/android/ndk for setting ANDROID_NDK_ROOT.

This will build armeabi target, to build for other targets such as arm64-v8a, armeabi-v7a, x86 see next section.

Building for other architectures

• Make sure to cleanup all existing binary and intermediate files, e.g:

  $ cd /path/to/your/pjsip/dir
  $ make clean
  
  # cleanup pjsua sample app
  $ cd pjsip-apps/src/pjsua/android/jni
  $ make clean
  
  # also cleanup pjsua2 sample app (SWIG)
  $ cd /path/to/your/pjsip/dir
  $ cd pjsip-apps/src/swig
  $ make clean
  

• Specify the target arch in TARGET_ABI and run it with --use-ndk-cflags, for example:

  TARGET_ABI=arm64-v8a ./configure-android --use-ndk-cflags
  

  Also you should adjust ​Application.mk and ​library packaging path (see also #1803).

Notes

• The ./configure-android is a wrapper that calls the standard ./configure script with settings suitable for Android target. Standard ./configure options should be applicable to this script too. Please check ./configure-android --help for more info.
• Other customizations are similar to what is explained in Building with GNU page.

Video Support

Features

Video on Android will be supported since PJSIP version 2.4. It has the following features:

• native capture
• native OpenGL ES 2.0 renderer (requires Android 2.2 (API level 8) or higher).
• H.264 codec (via OpenH264 library or AMediaCodec, see below)

Requirements

OpenH264 (this is recommended if you need H264 codec)

Provides video codec H.264, alternatively you can use ffmpeg (together with libx264).

1. Follow the instructions in ticket #1947.
2. Copy all library .so files into your Android application project directory, for example:

   cp /Users/me/openh264/android/*.so /Users/me/pjproject-2.0/pjsip-apps/src/swig/java/android/libs/armeabi
   

libvpx (if you need VP8 or VP9 codec)

​libvpx.

ffmpeg (optional)

Provides format conversion and video manipulation as well as video codecs: H.264 (together with libx264) and H263P/H263-1998.

1. Follow the instructions from the web on how to build ffmpeg for android. We followed the instructions provided ​here and successfully built with Android NDK r10.
2. Copy all library .so files into your Android application project directory, for example:

   cp /Users/me/src/ffmpeg-2.5/android/arm/lib/*.so /Users/me/pjproject-2.0/pjsip-apps/src/swig/java/android/libs/armeabi
   

AMediaCodec, native Android codecs (experimental)

This is available since 2.11, it provides H264, VP8, and VP9 video codecs (also AMR-NB & AMR-WB audio codecs). Please check ​here for how to enable it.

Configuring

To enable video, append this into config_site.h:

#define PJMEDIA_HAS_VIDEO 1

Specify third-party video libraries when invoking ./configure-android, e.g:

$ ./configure-android --with-openh264=/Users/me/openh264/android

Make sure openh264 is detected by ./configure-android:

...
Using OpenH264 prefix... /Users/me/openh264/android
checking OpenH264 availability... ok
...

Note: if you use PJSIP before version 2.6, you need to specify external libyuv via the configure script param --with-libyuv, check ticket #1776 for more info.

Adding Video Capture Device to Your Application

Copy the java part of PJSIP Android capture device to the application's source directory:

cp pjmedia/src/pjmedia-videodev/android/PjCamera*.java [your_app]/src/org/pjsip/

Using Video API

Please check Video User's Guide.

Video capture orientation support

To send video in the proper orientation (i.e. head always up regardless of the device orientation), application needs to do the following:

1. Setup the application to get orientation change notification (by adding android:configChanges="orientation|keyboardHidden|screenSize" in the application manifest file and override the callback onConfigurationChanged()).
2. Inside the callback, call PJSUA2 API VidDevManager.setCaptureOrient() to set the video device to the correct orientation.

For sample usage, please refer to pjsua2 sample app. Ticket #1861 explains this feature in detail.

OpenSSL Support

1. Build OpenSSL (tested with OpenSSL 1.0.2s) for Android. The instruction provided here is specifically for arm64. For other architectures, modify accordingly. Please visit ​this page for reference and some examples. Note: you need to change the NDK path and the API platform level below.

   cd openssl-1.0.2s
   
   export NDK=[your_android_ndk_path]/android-ndk-r17b
   
   $NDK/build/tools/make-standalone-toolchain.sh --platform=android-28 --toolchain=aarch64-linux-android-4.9 --install-dir=`pwd`/android-toolchain-arm64
   export TOOLCHAIN_PATH=`pwd`/android-toolchain-arm64/bin
   export TOOL=aarch64-linux-android
   export NDK_TOOLCHAIN_BASENAME=${TOOLCHAIN_PATH}/${TOOL}
   export CC=$NDK_TOOLCHAIN_BASENAME-gcc
   export CXX=$NDK_TOOLCHAIN_BASENAME-g++
   export LINK=${CXX}
   export LD=$NDK_TOOLCHAIN_BASENAME-ld
   export AR=$NDK_TOOLCHAIN_BASENAME-ar
   export RANLIB=$NDK_TOOLCHAIN_BASENAME-ranlib
   export STRIP=$NDK_TOOLCHAIN_BASENAME-strip
   export ARCH_FLAGS=
   export ARCH_LINK=
   export CPPFLAGS=" ${ARCH_FLAGS} -fpic -ffunction-sections -funwind-tables -fstack-protector -fno-strict-aliasing -finline-limit=64 "
   export CXXFLAGS=" ${ARCH_FLAGS} -fpic -ffunction-sections -funwind-tables -fstack-protector -fno-strict-aliasing -finline-limit=64 -frtti -fexceptions "
   export CFLAGS=" ${ARCH_FLAGS} -fpic -ffunction-sections -funwind-tables -fstack-protector -fno-strict-aliasing -finline-limit=64 "
   export LDFLAGS=" ${ARCH_LINK} "
   
   ./Configure android
   make
   

   Then copy the libraries into lib folder:

   mkdir lib
   cp lib*.a lib/
   

2. Specify OpenSSL location when running configure-android, for example (with Bash): (change the openssl path folder)

   TARGET_ABI=arm64-v8a ./configure-android --use-ndk-cflags --with-ssl=[your_openssl_path]/openssl-1.0.2a
   

   And check that OpenSSL is detected by the configure script:

   ...
   checking for OpenSSL installations..
   checking openssl/ssl.h usability... yes
   checking openssl/ssl.h presence... no
   aconfigure: WARNING: openssl/ssl.h: accepted by the compiler, rejected by the preprocessor!
   aconfigure: WARNING: openssl/ssl.h: proceeding with the compiler's result
   checking for openssl/ssl.h... yes
   checking for ERR_load_BIO_strings in -lcrypto... yes
   checking for SSL_library_init in -lssl... yes
   OpenSSL library found, SSL support enabled
   ...
   

3. Build the libraries:

   make dep && make
   

   If you encounter linking errors, you need to add this in user.mak:

   export LIBS += "-ldl -lz"
   

Trying our sample application and creating your own

Setting up the target device

To run or debug application (such as the sample applications below), first we need to setup the target device:

• using virtual device: ​http://developer.android.com/tools/devices/index.html
• using real device: ​http://developer.android.com/tools/device.html

Building and running pjsua2 sample application

A sample application using ​pjsua2 API with SWIG Java binding, is located under pjsip-apps/src/swig/java/android. It is not built by default, and you need ​SWIG to build it.

Follow these steps to build pjsua2 sample application:

1. Make sure SWIG is in the build environment PATH.
2. Run make from directory $PJDIR/pjsip-apps/src/swig (note that the Android NDK root should be in the PATH), e.g:

   $ cd /path/to/your/pjsip/dir
   $ cd pjsip-apps/src/swig
   $ make
   

   This step should produce:
   • native library libpjsua2.so in pjsip-apps/src/swig/java/android/app/src/main/jniLibs/armeabi
     • note: if you are building for other target ABI, you'll need to manually move libpjsua2.so to the appropriate target ABI directory, e.g: jniLibs/armeabi-v7a, please check ​here for target ABI directory names.
   • pjsua2 Java interface (a lot of .java files) in pjsip-apps/src/swig/java/android/app/src/main/java/org/pjsip/pjsua2
3. Make sure any library dependencies are copied to pjsip-apps/src/swig/java/android/app/src/main/jniLibs/armeabi (or the appropriate target ABI directory), e.g: libopenh264.so for video support.
4. Open pjsua2 app project in Android Studio, it is located in pjsip-apps/src/swig/java/android.
5. Run it.

Log output

The pjsua2 sample application will write log messages to LogCat window.

Creating your own application

For developing Android application, you should use ​pjsua2 API whose Java interface available via SWIG Java binding.

1. First, build pjproject libraries as described above.
2. Also build pjsua2 sample application as described above, this step is required to generate the pjsua2 Java interface and the native library.
3. Create Android application outside the PJSIP sources for your project.
4. Get pjsua2 Java interface and native library from pjsua2 sample application:
   1. Copy pjsua2 Java interface files from pjsip-apps/src/swig/java/android/app/src/main/java to your project's app/src/main/java folder, e.g:

      $ cd $YOUR_PROJECT_DIR/app/src/main/java
      $ cp -r $PJSIP_DIR/pjsip-apps/src/swig/java/android/app/src/main/java .
      
      # Cleanup excess pjsua2 application sources.
      $ rm -r org/pjsip/pjsua2/app
      

   2. Copy native library libpjsua2.so from pjsip-apps/src/swig/java/android/app/src/main/jniLibs to your project's app/src/main/jniLibs folder:

      $ cd $YOUR_PROJECT_DIR/app/src/main/jniLibs
      $ cp -r $PJSIP_DIR/{pjsip-apps/src/swig/java/android/app/src/main/jniLibs .
      

5. Start writing your application, please check ​pjsua2 docs for reference.

Pjsua sample application with telnet interface

There is also the usual ​pjsua with telnet command line user interface, which is located under pjsip-apps/src/pjsua/android. It is not built by default and you need ​SWIG to build it. Application flow and user interface are handled mainly in the native level, so it doesn't use pjsua2 API with Java interface.

Follow these steps to build pjsua:

1. Make sure SWIG is in the build environment PATH.
   • Alternatively, update SWIG path in $PJDIR/pjsip-apps/src/pjsua/android/jni/Makefile file.
2. Run make from directory $PJDIR/pjsip-apps/src/pjsua/android/jni (note that the Android NDK root should be in the PATH), e.g:

   $ cd /path/to/your/pjsip/dir
   $ cd pjsip-apps/src/pjsua/android/jni
   $ make
   

3. Open pjsua2 app project in Android Studio, it is located in pjsip-apps/src/pjsua/android.
4. Run it.
5. You will see telnet instructions on the device's screen. Telnet to this address to operate the application. See PJSUA CLI Manual for command reference.

Important Issue(s) when Developing Android Apps

Unable to Make or Receive Call (Problem with sending and receiving large (INVITE) requests over TCP)

The issue is documented in #1488. The solution is to try using port other than 5060 in *both* client and server, and/or reducing the SIP message size by following our FAQ here.

Garbage Collector May Crash Your App (Pjsua2 API)

Please check this pjsua2 book page about ​problems with GC.

OpenSLES audio device deadlock upon shutdown

As reported in ​Android NDK forum, when shutting down OpenSLES sound device backend, it may block forever:

W/libOpenSLES(6434): frameworks/wilhelm/src/itf/IBufferQueue.c:57: pthread 0x5fce71c0 (tid 6670) sees object 0x5fcd0080 was locked by pthread 0x5f3a2cb0 (tid 6497) at frameworks/wilhelm/src/itf/IObject.c:411

Currently, the only workaround is to use PJSIP's Android JNI sound device instead (one way to do this is by defining PJMEDIA_AUDIO_DEV_HAS_ANDROID_JNI to 1 and PJMEDIA_AUDIO_DEV_HAS_OPENSL to 0).

Bad audio recording quality on some devices

Reported that audio quality recorded on the microphone is bad and the speed is twice what it should be, it only happens on some devices. It could be fixed by setting audio mode via AudioManager to MODE_IN_COMMUNICATION in the application, e.g:

AudioManager am = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
int original_mode = am.getMode();

/* Set audio mode before using audio device, for example before making/answering a SIP call */
am.setMode(AudioManager.MODE_IN_COMMUNICATION);
...
/* Restore back to the original mode after finished with audio device */
am.setMode(original_mode);

UnsatisfiedLinkError exception with "Native method not found: org.pjsip.pjsua2.pjsua2JNI.swig_module_init" message

The reason might be:

• The Java interface files and/or the native library wasn't copied to the appropriate folder. Please have a look at here
• You built the lib using newer APP_PLATFORM on an older device. Please have a look at here

A review of Android audio output latency

For a review of Android audio output latency, please have a look at ticket #1841.

Other Android projects

Also have a look at the following PJSIP Android project:

• ​csipsimple project, an Android port of pjsip.