Wednesday, January 01, 2014

WebRTC app - C# / Xamarin - Part #1 - Building platform native webrtc library

This is a post in a series of postings

  1. WebRTC app - C# / Xamarin - Part #1 - Building platform native webrtc library
  2. WebRTC app - C# / Xamarin - Part #2 - Attempt #1 - failure to using a JNI .so file directly from C# / Mono
  3. WebRTC app - C# / Xamarin - Part #2 - Attempt #2 - success using a JNI .so file from C# / Mono
  4. WebRTC app - C# / Xamarin - (C# - JNI - C/C++) - Summary and GitHub repository
And finally the associated GitHub repository

I wish to build a cross platform app that supports WebRTC (real time communication - wikipedia article here). I would like to use Xamarin to achieve some level of code reuse between iOS and Android. There are several areas of the application that can use common code like the:
This series of blog postings will document my attempt at implementing the Android initial app (Mono.Android) and then I will attempt to move this to iOS (monotouch). Unlike some of my other postings this is a documentation project during the attempt to reach that goal.

Lets get started. 
Now building webrtc and all the associated libraries is not for the faint of heart, but luckily there are some pretty nice build tools available that does the job nicely. For both the Android and later the iOS edition we will need a C/C++ native compiled library that does all the heavy lifting with regards to audio/video rendering, decoding and encoding. So my first goal was to build a Android compatible library that I could include in my solution.

Here are some good links that got me started

and then I found this little gem at Ryazantsev's blog which basically walks you through the process step by step. I already had a Ubuntu 12.04 LTS virtual machine installed and configured so the below is the console commands run on my machine. I use some slightly modified commands compared to Ryazantsev's blog. Thanks to Ryazantsev for posting this great post.

##Installing JAVA (first install default JAVA)
sudo apt-get install python-software-properties
sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update && sudo apt-get install oracle-jdk7-installer
chmod a+x jdk-6u45-linux-x64.bin
mkdir /usr/lib/jvm
mv jdk1.6.0_45 /usr/lib/jvm/jdk1.6.0_45

##Update alternatives of java tools
sudo update-alternatives --install /usr/bin/javac javac /usr/lib/jvm/$jdir/bin/javac 1
sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/$jdir/bin/java 1
sudo update-alternatives --install /usr/bin/javaws javaws /usr/lib/jvm/$jdir/bin/javaws 1
sudo update-alternatives --install /usr/bin/jar jar /usr/lib/jvm/$jdir/bin/jar 1

##Check alternatives and java version
sudo update-alternatives --config javac
sudo update-alternatives --config java
sudo update-alternatives --config javaws
sudo update-alternatives --config jar
ls -la /etc/alternatives/{java,javac,javaws,jar}
java -version

echo 'export JAVA_HOME=/usr/lib/jvm/jdk1.6.0_45' >> ~/.bashrc
echo 'PATH="$PATH":`pwd`/depot_tools' >> ~/.bashrc
source ~/.bashrc
printenv | grep depot_tools
sudo apt-get install git subversion libpulse-dev g++ pkg-config gtk+-2.0 libnss3-dev
git clone

###Building WebRTC Trunk
cd ~
mkdir WebRTCDemo
cd WebRTCDemo/

gclient config
gclient sync
echo target_os = [\'android\', \'unix\'] >> .gclient
./trunk/build/  --no-chromeos-fonts
check  'sudo update-alternatives --config java ' for correct path
gclient sync
cd trunk
source ./build/android/
gclient runhooks
GYP_GENERATORS=ninja ./build/gyp_chromium --depth=. all.gyp 
ninja -C out/Debug -j10 All

After downloading all the files and building the project it takes up about 4.6GB on my disk in the virtual machine. Most source files in the project will show to be a good reference when we need to start using this in a Xamarin project. The really relevant parts through is the java sources for the Java version of the app (written by the WebRTC authors) as well as the Android compatible .so file.

The compiled .so file we need is available at 
The next posting will be attempt #1 in converting a Java app to a c# equivalent
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