Getting Started: Building for Android

1. Requirements
2. Build Preparation
3. Building PJSIP
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. Setting up the target device
6. Building and running pjsua2 sample application
   1. Log output
7. Creating your own application
8. Pjsua application with telnet interface
9. OpenSSL Support
10. 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. Build failure or configure-android error with "--use-ndk-cflags" using android-ndk-r13 or later
    6. UnsatisfiedLinkError exception with "cannot locate 'rand'" message
    7. UnsatisfiedLinkError exception with "Native method not found: org.pjsip.pjsua2.pjsua2JNI.swig_module_init" message
    8. A review of Android audio output latency
11. 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
  • Eclipse with ​ADT Plugin (deprecated since 2.6)
  • ​Android Studio
  • Telnet application to interact with PJSUA command line. If you are not familiar with telnet, please find a tutorial suitable for your development platform.

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

Notes:

• It will build armeabi target, to build for other targets such as arm64-v8a, armeabi-v7a, x86, instead of just './configure-android', specify the target arch in TARGET_ABI and run it with --use-ndk-cflags, for example:

  TARGET_ABI=armeabi-v7a ./configure-android --use-ndk-cflags
  

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

Requirements

OpenH264 (recommended)

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

1. Follow the instructions in ticket #1947 (or ticket #1758 if you use PJSIP before version 2.6).
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
   

libyuv (recommended)

Provides format conversion and video manipulation, alternatively you can use ffmpeg. If you are using 2.5.5 or newer, libyuv should be built and enabled automatically, see ticket #1937 for more info. If you are using 2.5.1 or older:

1. Follow the instructions in ticket #1776
2. Copy all library .so files into your Android application project directory, for example:

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

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
   

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.

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 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.

OpenSSL Support

1. Build OpenSSL (tested with OpenSSL 1.0.2a) 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: change the NDK path below.

   cd openssl-1.0.2a
   
   export NDK=[your_android_ndk_path]/android-ndk-r10d
   
   $NDK/build/tools/make-standalone-toolchain.sh --platform=android-21 --toolchain=aarch64-linux-android-4.9 --install-dir=`pwd`/android-toolchain-arm64
   export TOOLCHAIN_PATH=`pwd`/android-toolchain-arm64/bin
   export TOOL=aarch64-linux-android
   export NDK_TOOLCHAIN_BASENAME=${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"
   

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);

Build failure or configure-android error with "--use-ndk-cflags" using android-ndk-r13 or later

Release notes to r13 stated that NDK_TOOLCHAIN_VERSION now defaults to Clang, resulting error on configure-android which expects gcc:

configure-android error: compiler not found, please check environment settings (TARGET_ABI, etc)

It can also cause PJSIP to fail to build on android-ndk-r15.

As a workaround, you can specify NDK_TOOLCHAIN_VERSION (to 4.9) to use gcc.

NDK_TOOLCHAIN_VERSION=4.9 TARGET_ABI=armeabi-v7a ./configure-android --use-ndk-cflags

UnsatisfiedLinkError exception with "cannot locate 'rand'" message

This may occur when running pjsua2 sample app:

Exception Ljava/lang/UnsatisfiedLinkError; thrown while initializing Lorg/pjsip/pjsua2/app/MyApp;
...
java.lang.UnsatisfiedLinkError: Cannot load library: reloc_library[1285]:    37 cannot locate 'rand'...

As described ​here, this happens if you've built your native components with the android-21 target, but are trying to run it on a device with an older Android version, so re-run configure with APP_PLATFORM set to lower platform version, e.g:

APP_PLATFORM=android-19 ./configure-android

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.