MediaStreaming - Videocall

Repository for the Videocall of Media Streaming Module (T3.3).

Video Call

This part of the app creates a P2P video call between two users connected to the same signalling server. If the clients are communicating using different networks, this communication could be blocked, not offering well the video. To avoid tihs we use a Turn server.

This module accept the next parameters:

  • Room name
  • Signaling server
  • Turn Server
  • Turn User
  • Turn Credential
  • Stun Server

By default, if the parameters are not provided, the next configuration is used:

  • Signaling server:
  • TURN server: turn:
  • TURN user: user1
  • TURN credential: (See value in values/string.xml)
  • STUN server: stun:
  • Room Name: test_room

All these values can be modified in the values/strings.xml file.

This module can be tested using, e.g the MediaStreaming App through the VideoCall Option.

MediaStreaming App

Once selected the option, we can introduce the room name

VideoCall Room Name

and the rest of the parameters using the Setting option.

VideoCall Settings

After of this, we can Start the Call.

How to use Video Call

This module generates a .aar file to be included in your applications as a dependency. See more details at Multiproject dependencies chapter.

To call the extension from your application, include in your activity the room_name, signaling_url, turn_url, turn_user, turn_credential and stun_url parameters.

    Intent videoCallIntent = new Intent(MainActivity.this, VideoCallActivity.class);
	videoCallIntent.putExtra("room_name", "test_room");	
	videoCallIntent.putExtra("TURN_URL", TURN_URL);
	videoCallIntent.putExtra("TURN_user", TURN_user);
	videoCallIntent.putExtra("TURN_credential", TURN_credential);
	videoCallIntent.putExtra("STUN_URL", STUN_URL);
	videoCallIntent.putExtra("API_endpoint", API_endpoint);

Request permissions

Before start activity of the video call intent:

    if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED
    || ContextCompat.checkSelfPermission(this, Manifest.permission.RECORD_AUDIO) != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA, Manifest.permission.RECORD_AUDIO}, ALL_PERMISSIONS_CODE);

How to develope

Download VideoCall code

git clone

  • Open Android Studio and open an existing project from the directory of your code downloaded. To install Android Studio follow the next link:

  • To generate an aar file from the code, select the Build option in the Menu Bar, select ReBuild project or choose Make Project icon as you can see in the picture. Once generated, you can find the file in app/build/options/aar (you can rename the file as you like):

Build aar file

Multiproject dependencies

HELIOS software components are organized into different repositories so that these components can be developed separately avoiding many conflicts in code integration. However, the modules also depend on each other.

How to configure the dependencies

To manage project dependencies developed by the consortium, the approach proposed is to use a private Maven repository with Nexus.

To avoid clone all dependencies projects in local, to compile the "father" project. Otherwise, a developer should have all the projects locally to be able to compile. Using Nexus, the dependencies are located in a remote repository, available to compile, as described in the next section. Also to improve the automation for deploy, versioning and distribution of the project.

How to use the HELIOS Nexus

Similar to other dependencies available in Maven Central, Google or others repositories. In this case we specify the Nexus repository provided by Atos:

This URL makes the project dependencies available.

To access, we simply need credentials, that we will define locally in the variables heliosUser and heliosPassword.

The build.gradle of the project define the Nexus repository and the credential variables in this way:

repositories {
        maven {
            url ""
            credentials {
                username = heliosUser
                password = heliosPassword

And the variables of Nexus's credentials are stored locally at ~/.gradle/


To request Nexus username and password, contact with:

How to deploy a new version of the dependencies

Let's say that we want to deploy a new version of the videocall project. This project is a dependency of MediaStreaming. For Continuous Integration we use Jenkins. It deploys the configured projects (e.g., videocall) in different jobs, and the results are libraries packaged like AAR (Android ARchive). These packaged libraries are upload to Nexus and in this way, they are available to build the projects that depend on them (e.g., MediaStreaming). In the videocall example, Jenkins jobs generate automatically and aar library and store it at the Nexus repository to make it available.

Jenkins is the tool deployed by Atos (WP6 leader) in HELIOS to automate the generation of APKs, joining all the project modules. Due to the need of managing the dependencies, Atos has selected additional tools, as explained in this document.

After pushing a change to the master branch, the maintainer can builds the module by means of the job in the Jenkins interface. GitLab repositories are set to protect the master branch push and merge for the partner in charge of its module/project (maintainer).

To request Jenkins username and password, contact with:

How to use the dependencies

To use the dependency in build.gradle of the "father" project, you should specify the last version available in Nexus, related to the last Jenkins's deploy. For example, to declare the dependency on the videocall module and the respective version:

implementation 'eu.h2020.helios_social.modules.videocall:videocall:1.0.36'

For more info review:

Hot to use the dependencies locally

If you want to include the .aar file generated as a dependency in the application whitout use Nexus dependencies:

  • Go to your application code and create libs folder inside app folder:

libs folder

  • Open build.gradle at Project level and add flatDir{dirs 'libs'} :

Project build.gradle

allprojects {
   repositories {
      flatDir {
        dirs 'libs'
  • Open build.gradle at app level and add .aar file:

app build.gradle

dependencies {
     compile(name:'file_name', ext:'aar')

VideoCall module storage

The module implements a local storage system to communicate clients through the Signaling and Turn/Stun servers. These servers are packaged in Docker containers.

See more info at:

VideoCall local storage implementation

License: MIT