AprilCat / android-videostreamdecodingsample-webrtc

Android sample to obtain video from a DJI drone and transport that via WebRTC to a consumer

Android Video Stream Decoding Sample

Introduction

This project is derived from the original DJI sample project Android-VideoStreamDecodingSample. It utilizes the Mobile DJI Drone SDK for Android and the DJI Streamer Lib in order to enable WebRTC video streaming from the drone's camera via an Android device to another WebRTC client.

For details regarding the DJI sample app please refer to the original Android-VideoStreamDecodingSample.

Prerequisites

You need to have:

• a DJI drone with a Remote Control and an Android device running at least Android 7.
• a DJI developer account.
• a registered DJI SDK API key, you can use the original package name for registration (com.dji.videostreamdecodingsample). You need to configure this key in AndroidManifest.xml.
• a credential consisting of a user Id and a license key for being able to use the DJI Streamer Lib which brings WebRTC connectivity to the DJI drone . You can either contact our technical support for details or checkout the self-provisioning service at WebRTC Signalling Server.
• a bit of Android developer skills and a recent version of Android Studio plus the Android SDK installed on your machine.
• an Internet access.

What does this sample project do?

The sample demonstrates how to enable your Android device to be ready for incoming WebRTC calls from another party in order to forward the video from the connected drone in real-timeto a consumer. The other party can either use our WebRTC Signalling Server or any other WebRTC client (e.g. GStreamer). The easiest way for a first instant success it to use the WebRTC Signalling Server.

Whereas the ConnectionActivity.java class is widely the unchanged original, the MainActivity.java has been completely refactored. It now contains GLSurfaceView for displaying the decoded video and a Start button to enable WebRTC functionality.

On Start the app immediately begins to obtain H.264 from the drone's camera and displays the decoded YUV signal in the GLSurfaceView. In parallel it contacts a WebRTC signalling server, using the credential tuple (userId, licenseKey), which has been obtained earlier as described above. If the login process is successful, the app is ready for incoming calls, which can be issued by either the WebRTC Signalling Server.

You can hangup and call again from remote, but once you hit Stop, the library respectively the Android app will not respond to calls anymore, until the next Start happens.

In case the colors displayed look weird, play a bit with the StreamerConfig.setYuvFormat() function.

For details for the API provided by the DJI Streamer Lib please refer to the DJI Streamer Lib.

What are you supposed to do?

• Clone this repository and open it in Android Studio.
• Provide your DJI SDK key in AndroidManifest.xml. The place is marked.
• Provide your DJI Streamer Lib credential tuple in MainActivity.java. The place is marked.
• Compile and install the app on your Android device, which is connected to the Remote Control of the drone via USB. It goes without saying, that all connected devices should be powered up. You cannot run this app on an emulator.
• Once the app is installed, you will be asked whenever you plug the RC via USB, which application you would like to run. Choose this, but not as a permanent choice.
• Follow the little tutorial above regarding the Start/Stop functionality.

Note

Since this app deals with some large files it might be necessary to checkout the statement regarding git lfs from the original sample Android-VideoStreamDecodingSample. We haven't found a real reason for this requirement, since the largest file is about 50 MB "only", but you never know.

Status

This application as well as the DJI Streamer Lib is beta and has been successfully tested on a DJI Mavic Pro and a DJI Spark.