How to compile and build SilentPhone

SilentPhone consists of two major parts: the Android Java modules and their associated layout files, resources files, and generated source and resource files. The second part is C/C++ based the phone engine which includes the SIP, RTP, ZRTP, TLS, and codec handling among some other functions. The Java part uses standard JNI techniques to communicate with the C/C++ parts.

Prerequisites

This short description assumes that you have a good understanding of the Android SDK, the Android NDK, and their build procedures.

To compile and build SilentPhone you require a full Android development environment that includes the Android Java SDK and the Android NDK (Native Development Kit). Because SilentPhone shall support Android API 10 (Gingerbread 2.3.x) make sure you also download and install the necessary SDK modules. Furthermore I recommend to use the Eclipse Android SDK extensions.

Directory structure

SilentPhone uses a set of sources that must be compiled and linked together. To simplify development we have set up a specific directory structure that contains the sources and build files. In the following figure $SRC_ROOT denotes the root directory of this specific directory layout. The figure does not show every directory, only the top level and relevant directories.

$SRC_ROOT
 |
 |-- tivi                       # Root for SilentPhone, Tivi C/C++ sources
 |   |-- libs
 |   |   |-- polarssl-1.1.1     # PolarSSL 1.1.1 sources
 |   |   `-- libzrtptivi-3.0.0  # ZRTP lib sources (see remark below)
 |   |-- scandroid              # SilentPhone Android main directory
 |   |   |-- assets
 |   |   |-- bin
 |   |   |-- gen
 |   |   |-- jni
 |   |   |-- libs
 |   |   |-- obj
 |   |   |-- res
 |   |   |-- src
 |   |-- sources                # Main directory for C/C++ sources
 |   |   |-- android
 |   |   |-- apple
 |   |   |-- audio
 |   |   |-- baseclasses
 |   |   |-- codecs
 |   |   |-- encrypt
 |   |   |-- gui
 |   |   |-- ios
 |   |   |-- os
 |   |   |-- rtp
 |   |   |-- sdp
 |   |   |-- sipparser
 |   |   |-- stun
 |   |   |-- tiviandroid
 |   |   |-- tiviengine
 |   |   |-- tools
 |   |   |-- uml
 |   |   |-- utils
 |   |   |-- video
 |   |   |-- winpc
 |   |   `-- xml
 |   `-- tina
 `-- zrtpcpp                    # Development directory for ZRTP
     |-- bnlib
     |-- clients
     |   |-- ccrtp
     |   `-- tivi               # Tivi (iOS, Android) extensions
     |-- cmake
     |-- common
     |-- cryptcommon
     |-- demo
     |-- doc
     |-- srtp
     `-- zrtp

NOTES:

• Depending on the development environment you may either use the libs/libzrtptivi-3.0.0 directory or the main zrtpcpp directory. The libs subdirectory shall contain a stable version of the ZRTP/SRTP sources and the zrtpcpp directory may contain a development version. In any case the ZRTP directories must contain the non-public extensions for the Tivi client.
• The directory name scandroid is not fixed and you may choose a different name. However, this directory shall be at this position in the directory structure.
• The directory names tivi, zrtpcpp, and libzrtptivi-3.0.0 are not fixed. If you use different names you must adapt the names in the Android NDK build files.

Building the SilentPhone client from exising Git repository

SilentPhone's Git repository contains all necessary shared libraries to build the required shared library and to install it. After cloning the repository you should perform a build for the shared libraries to make sure all libraries are installed in their correct places.

After that step you can build SilentPhone. Either setup an Eclipse Android project or use the ant command line tools to generate the application package.

NOTE: After the SilentPhone code basis becomes more stable we may put the libraries also into the Git repository. This saves the extra build step.

Building the shared libraries

After you built the library once it's usually not necessary to re-build it, except you need to fix a problem inside the library code.

The directory scandroid/jni contains the build files to compile and link the shared libraries for SilentPhone. Depending on your directory setup and naming you need to adapt some lines in jni/Android.mk. The build files assumes the shown directory structure.

The Android.mk file contains two ifeq sections that show how to define the path names for different environments. Use this as a template to setup your own path names.

If required you may also adapt the line that defines ZRTP_SRC_PATH to point to the correct ZRTP source directory. Some comments in Android.mk already show two different configurations.

After you adapted the build files you may just run ndk-build from the command line. The NDK build script copies the shared libraries to their correct places inside the Android project. Now you can build the SilentPhone client with either the Eclipse Android extensions and with the ant command line tool.