Intel® Collaboration Suite for WebRTC  version 4.3
Open WebRTC Toolkit (OWT) Client SDK for Android*
Open WebRTC Toolkit Client Android SDK Documentation

1 Introduction

Open WebRTC Toolkit Client SDK for Android, OWT Android briefly, provides helpful tools (including a sample Android application) for developing Android native WebRTC applications using Java APIs. The SDK is distributed in the CS_WebRTC_Client_SDK_Android.<ver>.zip release package.

Please refer to the Release Notes for the latest information in the SDK release package, including new features, fixed bugs and known issues.

2 Supported platforms

OWT Android requires using Android SDK API level 16 or above. In order to use hardware media codec, API level 19 is recommended.

The following devices have been validated with our SDK:

  • Huawei* Mate20 (Android 9.0)
  • Huawei* Mate9 (Android 7.0)
  • Huawei* NXT-AL10 (Android 6.0)
  • Huawei* P20 (Android 8.1)
  • Huawei* P8 (Android 5.0)
  • Nexus 5X (Android 7.1.1)
  • Nexus 6P (Android 8.0.0)
  • OPPO* R17 (Android 8.1.0)
  • Sumsung* S8 (Android 7.0)
  • Sumsung* S6 (Android 6.0.1)
  • vivo* X23 (Android 8.1.0)

Note: Some HUAWEI devices should adding white-listed video codecs in extra config file in /sdcard/mediaCodec.xml example in section 4.1.

3 Development

3.1 Prerequisite

First, be sure to install the prerequisite software.

  1. Download Android Studio*
  2. Install the Android SDK with target API level 16 or above
  3. Configure Android SDK path for gradle: create file in project root directory and add the following line to it:

3.2 Sample applications

Sample Android application projects are provided along with OWT Android release package, including a peer-to-peer application and a conference application. To build and run sample apps, please follow below steps: Please notice that there are some linux format link files in sample dependency folders, modify them before you run on a different platform.

3.2.1 Run samples with Android Studio

  1. Open Android Studio
  2. Import sample project by "Open an existing Android Studio project"
  3. Build and run samples

3.2.2 Run samples with Gradle in the console

  cd /path/to/dist/samples/folder
  ./gradlew assembleRelease

Apk files will be located in build/outputs/apk folder.

3.3 Developing Android applications with OWT Android

Follow these general steps to create an Android application using OWT Android:

  1. Create an Android Application project in Android Studio.
  2. Create a libs/ folder under the project directory.
  3. Copy owt_base.jar and owt_p2p.jar(or owt_conference.jar) from the libs/ folder in release package to the libs/ folder created in step 2.
  4. Create jniLibs/ folder under project/src/main directory.
  5. Copy the from libs/webrtc/<target_arch> of our Android client SDKto jniLibs/<target_arch> folders.
  6. Add all the JAR (Java archive) files dependencies in your project build.gradle.
  7. Now start to develop your own Android application using the P2P and/or Conference APIs.

Note: Upon initialization, ContextInitialization.initialize() is required to be called. The Context parameter should be the launch activity your application runs, and you should create an EglBase object in your launch activity and then pass the EGLContext to the second parameter. More details please refer to the sample applications.

Note: You may need to add or require specific permissions for your application.

4 Media codecs

4.1 Video codecs

OWT Android supports VP8, VP9, H.264 and HEVC video codecs depending on the device hardware. Use the following APIs to set the preferred video codec:

  • owt.conference.PublishOptions.addVideoParameter
  • owt.conference.SubscribeOptions.setVideoOption
  • owt.p2p.P2PClientConfiguration.addVideoParameters

Note: Hardware encoder/decoder requires Android API level 19 or fabove.

OWT AndroidSDK supports adding white-listed video codecs in extra config file in /sdcard/mediaCodec.xml; A sample config file is shown below:

        <MediaCodec name="OMX.IMG.TOPAZ.VIDEO.Encoder" type="video/avc">
        <MediaCodec name="OMX.MTK.VIDEO.ENCODER.VPX" type="video/x-vnd.on2.vp8">
        <MediaCodec name="" type="video/hevc">
        <MediaCodec name="" type="video/x-vnd.on2.vp9">
        <MediaCodec name="OMX.IMG.MSVDX.Decoder.AVC" type="video/avc">
        <MediaCodec name="OMX.MTK.VIDEO.DECODER.VPX" type="video/x-vnd.on2.vp8">
        <MediaCodec name="OMX.MTK.VIDEO.DECODER.HEVC" type="video/hevc"> 

4.2 Audio codecs

OWT Android supports PCMU, OPUS and other codecs depending on the device hardware. Use the following API to set the preferred audio codec for recording:

  • owt.conference.PublishOptions.addAudioParameter
  • owt.conference.SubscribeOptions.setAudioOption
  • owt.p2p.P2PClientConfiguration.addAudioParameters

5 NAT and firewall traversal

OWT Android fully supports NAT and firewall traversal with STUN / TURN / ICE. The Coturn TURN server could be one choice.

6 Customize signaling channel

Signaling channel is an implementation to transmit signaling data for creating a WebRTC session. Signaling channel for P2P sessions can be customized by implementing SignalingChannelInterface. We provide a default SocketSignalingChannel in sample which works with PeerServer in the release package.

P2PClient implements SignalingChannelObserver, so you can invoke its methods to notify P2PClient when a new message is coming or the connection is lost.

7 Customize renderer

OWT Android uses org.webrtc.SurfaceViewRenderer in the sample apps, which can be used to render a stream on a SurfaceView. If you would like to customize your own renderer, follow these steps:

  1. Create your own renderer class which implements the interface org.webrtc.VideoRenderer.Callbacks;
  2. In the renderer class you have to implement the method renderFrame(org.webrtc.VideoRenderer.I420Frame);
  3. The frames will be passed to renderFrame(). So in this method you can use your own way to render each frame;
  4. Every time you finish rendering a frame, you must call org.webrtc.VideoRenderer.renderFrameDone(frame).

8 Customize SSL context

Conference SDK allows customized SSL context when connecting to MCU server. That means you can change the behavior of how client verifies server's certificate. This may be useful if you want to use self-signed certificate during development. Make sure your SSL context is secure enough when using it in production environment. To use a customized SSL context, please use APIs below:

  • owt.conference.ConferenceClientConfiguration.setSSLContext
  • owt.conference.ConferenceClientConfiguration.setHostnameVerifier

Please refer to detailed description of SSL/TLS.

9 Customize video input

Instead of getting video frames from device camera, OWT Android allows customizing video input which enables media stream to get video frames from the source that application customizes. To set a customized video input, please follow these steps:

  1. Implement owt.base.VideoCapturer interface;
  2. Create owt.base.LocalStream with the object instance of the class implemented in step 1;

10 Customize video encoder/decoder

Instead of using Android mediacodec APIs to utilize hardware codes on the devices, OWT Android allows customizing video encoder/decoder to encode/decode video streams.

11 Privacy and security

SDK will send operation system's name and version, libwebrtc version and abilities, SDK name and version to conference server and P2P endpoints it tries to make connection. SDK does not store this information on disk.

Note: * Other names and brands may be claimed as the property of others.