An Android application that uses RTI Connext DDS and the open source gstreamer multimedia framework to send a live video stream from one Android device to another.
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RTI Video Demo For Android, rtivideodemo-android

An Android application that uses RTI Connext DDS and the open source gstreamer multimedia framework to send a live video stream from one Android device to another.

You can get the project for this demo with a precompiled .apk from github,

This demo is also compatible with the Distributed Video Demo that shows video streaming on a PC using RTI Connext. That demo is available from

NOTE: This demo uses GStreamer 1.0 to encode (compress) the raw video stream received from the Android device's camera using VP8. VP8 is the compression method that is used by WebM, which is use by HTML5.

NOTE: You will see a noticeable delay in the capture of the video on one device to the display on another device. The source of this delay is entirely within the VP8 encoding/decoding done entirely by GStreamer 1.0 VP8 software plugins. There is no delay due to the use of DDS itself.

If the demo was modified to take advantage of the hardware video processing capability offered by many modern video devices (phone and PC web cameras), there would be noticeable decrease in the delay. However, this demo was created to run on any generic Android device and does not require specific hardware video-processing support.

Getting Started

  1. Installing rtivideodemo-android.apk on a real Android Device

    It will show as the "Connext Video Demo" icon.

    A. Attach your Device via USB (to a PC where you have the .apk file)

    B. Enable your Device to install apps from unknown sources. On Device, use Settings -> Security -> Unknown Sources, check the checkbox

    C. Optional, enable your Device to allow debugging over USB On Device, use Settings -> Developer options -> USB debugging, check the checkbox. NOTE: You may need to enable the Developer options menu option on some devices. e.g., on Nexus 7, use Settings -> About tablet -> Build number, select Build number 10 times (or so)

    D. Installing the .apk

     1. Using the rtivideodemo-android.apk directly
       The .apk is located in 'bin/rtivideodemo-android.apk' in the
       rtivideodemo-android project.
       You install the rtivideodemo-android.apk by either
       * Copying 'rtivideodemo-android.apk' to your Device's
         filesystem mounted via USB. 
         Use a file manager app (which you'll need to install from
         Google Play, many free ones available) to select and
         install the .apk on your Device.
         Select the installed rtivideodemo-android icon to run.
       * or from a command line on your PC, running: 
               adb install rtivideodemo-android.apk
         'adb.exe' must be executable from your command line.
  2. Using Eclipse

    From the toolbar use Run -> Run . This will automatically build the project (so project must successfully build, see #Building below)

    The dialog, Android Device Chooser, may popup and show your device if you have more than 1 Android device connected via USB.

    If an Android device emulator pops up or if your device is not shown as "online", you probably need to go to the Device itself which has popped up a dialog asking you for permission to allow your computer to connect via USB for debugging. (note, while the demo will start in an emulator, it will not be able to connect to another device since the emulator's network setup is not the same as a real device)

    Select your device in the Android Device Chooser if needed.

    The rtivideodemo-android.apk will automatically be installed and started.

    You can use the CDT Build Console and the Android Console to monitor the build/installation process. You can open a LogCat console to see the debug messages coming from the rtivideodemo-android application.


  1. "Connext Video Demo" is configured to work using Android's WiFi network interface, so your device should be connected to a WiFi network.

    NOTE: The demo uses RTI Connext DDS to send a video stream to another Android device or to a PC via the WiFi. This means that your device must be able to connect to another device (or a PC) via the WiFi. If you are on a WiFi that requires a login via a web page after initial connection (for example at a hotel or conference hall, or using a roaming service such as Boingo), those types of connections actually don't allow one device connected to the WiFi from directly connecting to another device on the same WiFi. So this demo will not work in that setup.

    It will work on a local WiFi router (even if the WiFi connection requires a WEP or WPA authentication key).

    NOTE: If your Android devices support WiFfi-Direct (for example a Nexus 7),, you can use this to connect your devices directly to each other via WiFi and have the demo stream from one device to another.

  2. You will need at least 2 devices running "Connext Video Demo" or a compatible video demo on a PC, for example from

  3. Start the "Connext Video Demo" on both devices. By default, the demo will start in Publish mode, which means that it will attach to the video camera of the device and publish a video stream via RTI Connext DDS. So, you will have to change one of the devices to Subscribe mode so that it will receive and display the video stream from the other device.

    In the app, select "Sub". Wait until the app switches to "Sub" and then hit the "Start" button which will subscribe to the data stream. To view the stream, you will have to hit the "Play" arrow button.

    You may need to start the publishing app by hitting the "Start" button as well as the "Play" arrow to begin streaming.

  4. See Troubleshooting section below if you can't get a video stream from one app to the another.


These instructions are for a Windows development host.

  1. You need to have Eclipse and the Android ADT plugin installed. The Android ADT plugin depends on the Android SDK. You can:

    A. Install the Eclipse ADT Bundle, which has Eclipse with ADT in a single installer.

    Use this if you don't have Eclipse on your computer yet. Look
    for the Download the [SDK ADT Bundle for Windows
    link]( and follow
    [these instructions]

    B. Install the ADT plugin and Android SDK separately.

    Use this if you already have an Eclipse installation that you
    want to use. Look for the ["Use an existing IDE"
    link]( and follow
    [these instructions]

    C. After installation, if in Eclipse, you don't see the Android SDK, manager and Android Virtual Device Manager menu options under the Window toolbar menu, then open Window -> Customize Perspective -> Command Groups Availability tab, check Android SDK and AVD Manager.

  2. Use the Android SDK Manager to install the Android platforms for which you want to build (e.g., Android 4.1.2, Android 4.2.2, Android 4.3, etc.). Make use that you run the Android SDK Manager with Adminstrator Priviledges if on Windows, or else you won't be able to install any of the SDKs.

  3. Install the Android NDK (native cross-compiler for Android/ARMv7). Needed to compile C/C++ code invoked through JNI on Android.

    NDK 9 or higher is required.

    Go to and follow [these instructions] ( Note that you don't need the legacy NDK toolchains.

  4. Install RTI Connext DDS (and Android target libraries)

    You'll need to get this from your local RTI representative. Contact to find out who this is.

  5. Download and install GStreamer libraries for Android

    rtivideodemo-android works with gstreamer 1.3.90 and higher.

  6. Open rtivideodemo-android project in Eclipse

    A. Start Eclipse

    B. Use File -> Import -> Existing Projects into Workspace

    C. Select the directory where the project rtivideodemo-android is located.

  7. Customize the project to reflect your environment.

    A. Right click on rtivideodemo-android folder in Project Explorer,

    Open Properties -> C/C++ Build -> Environment

    B. Change the value of NDDSHOME and GSTREAMER_SDK_ROOT_ANDROID to reflect where you installed RTI Connext DDS and GGtreamer

    C. If you haven't done so already, you also need to make sure that Eclipse knows where your Android NDK is installed.

    Open Window -> Preferences -> Android -> NDK, and edit NDK Location

  8. Build Project

    Use Project -> Build Project. The Output in the (CDT Build) Console should look like:

    13:42:24 **** Incremental Build of configuration Default for project rtivideodemo-android ****

    "C:\Apps\android-ndk-r9\ndk-build.cmd" all GStreamer : [GEN] => gst-build-armeabi-v7a/gstreamer_android.c GStreamer : [COMPILE] => gst-build-armeabi-v7a/gstreamer_android.c GStreamer : [LINK] => gst-build-armeabi-v7a/ Prebuilt : <= gst-build-armeabi-v7a/ Install : => libs/armeabi-v7a/ Install : => libs/armeabi-v7a/ Install : => libs/armeabi-v7a/ Install : => libs/armeabi-v7a/ "Compile++ thumb : rti_android_videodemo <= ConnextGstreamer.cxx SharedLibrary : Install : => libs/armeabi-v7a/ Install : => libs/armeabi-v7a/

13:42:43 Build Finished (took 18s.243ms)

  1. Install APK and run on Android device

    Use Run -> Run from the Eclipse toolbar, or right click on the project and use Run As -> Android Application. This will kick off a build and then automatically install the .apk on to your Android device and start the app.

    If you have more than one Android device plugged in, you may need to select the device that you want to run on from the Android Device Chooser that will pop up.

    If your device does not show up, or Eclipse starts an Android Emulator, it is likely that you need to configure your device to allow for USB debugging and likely to select "Allow" on your device when your device detects your computer trying to establish a USB debug session.

    NOTE: While the demo will start in an Android emulator, it will not be able to connect to another device since the emulator's network setup is not the same as a real device.

    You can use the CDT Build Console and the Android Console to monitor the build/installation process. You can open a LogCat console to see the debug messages coming from the rtivideodemo-android application.

    Example Android Console output:

[2014-08-11 14:09:36 - rtivideodemo-android] ------------------------------ [2014-08-11 14:09:36 - rtivideodemo-android] Android Launch! [2014-08-11 14:09:36 - rtivideodemo-android] adb is running normally. [2014-08-11 14:09:36 - rtivideodemo-android] Performing activity launch [2014-08-11 14:09:36 - rtivideodemo-android] Automatic Target Mode: using device 'SH18JT501845' [2014-08-11 14:09:36 - rtivideodemo-android] Uploading rtivideodemo-android.apk onto device 'SH18JT501845' [2014-08-11 14:09:39 - rtivideodemo-android] Installing rtivideodemo-android.apk... [2014-08-11 14:10:12 - rtivideodemo-android] Success! [2014-08-11 14:10:12 - rtivideodemo-android] Starting activity on device SH18JT501845 [2014-08-11 14:10:16 - rtivideodemo-android] ActivityManager: Starting: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] }


  1. rtivideodemo-android doesn't seem to connect (you don't see a live video feed sent from one device to another)

    If your Android devices on are different subnets or multicast is not supported on the WiFi network, then you should use NDDS_DISCOVERY_PEERS environment variable to set the IP addresses of the devices as the initial peers for discovery.

    An Android device IP address on WiFi can be found using Settings -> WiFi -> < whatever WiFi network is connected >.

    You can set the IP address in the Peer List for the demo on the Android device using the "..." (3 dots menu) -> Settings -> DDS Peer List preferences menu option.

    NOTE: If the Android devices are connected to a WiFi that requires a login (I don't mean a password for WEP or WPA/PSK WiFi security), then it is likely that your two devices will not be able to connect to each other. This is true for most conference center, hotel or roaming WiFi services like Boingo. Those WiFi services simply don't allow you to directly connect two devices on their network.

  2. Build problems?

    A. Make sure that Eclipse knows where your NDK is located

    Set Eclipse -> Window -> Preferences -> Android -> NDK to the
    location of your Android NDK installation

    B. Your build never completes...and you have to kill Eclipse (or at least kill the build processes that were spawned by Eclipse).

    Not sure why, but the Scanner...that Eclipse runs for C/C++
    which basically creates the information needed for the Eclipse
    editor to flag syntax and other coding errors that usually is
    only found during compilation, but now can be dynamically
    detected if the code scanner invoked by Eclipse does its
    job...gets stuck and never finishes.
    Solution, disable the scanner.
    Open the properties for the rtivideodemo-android project ->
    Builders -> unselect Scanner Configuration Builder.

    C. After disabling your Scanner Configuration Builder, your project now complains that there are errors in the code after a build and now refuses to create, install and run an .apk. Since disabling the Scanner now prevents the Eclipse editor from successfuly verifying the syntax of your C/C++ code, it now flags unknown variable types and such as errors (which really aren't since the compiler is the one will work fine).

    To prevent the editor from flagging syntax errors that really
    aren't errors,
    Open the properties for the rtivideodemo-android project ->
    C/C++ General -> Code Analysis 
    -> uncheck Syntax and Semantic Errors.

File Descriptions


  • 'src/com/rti/android/videodemo/' - The main Android activity for rtivideodemo-android. Handles all of the button actions that switches between video camera and video display modes.

  • 'src/com/rti/android/videodemo/' - Class that runs the demo when in Camera (Pub) mode. Connects the device camera to the underlying Connext DDS/GStreamer processing pipeline.

  • 'src/com/rti/android/videodemo/' - Class that runs the demo when in Display (Sub) mode. Connects the underlying Connext DDS/GStreamer processing pipeline to a display surface to display the incoming video stream.

  • 'src/com/rti/android/videodemo/' - Abstract class that serves as the base class for VideoCamera and VideoDisplay. Allows buttons in the MainActivity to function correctly independently of the mode that the demo is in.

  • 'src/com/rti/android/videodemo/' - Class that wraps the underlying C functions provided by the ConnextGstreamer.cxx file into equivalent Java methods via JNI.

  • 'src/com/rti/android/videodemo/' - Android Activity used to create "Settings" option menu.

  • 'src/com/rti/android/videodemo/util/' - Useful class so that when a preference (setting/option) is changed by the user, the new value is automatically reflected in the preferences menu.

JNI - C/C++

  • 'jni/ConnextGstreamer.cxx' - Wrapper using RTI Connext DDS and GStreamer invoked via JNI interface. The wrapper creates DDS entities such as DDSParticipants, DDSDataWriters, DDSDataReaders as well as creates the GStreamer video processing pipelines. You would modify this file if you want to try different video compression algorithms or try to use a device's onboard video encoding/decoding hardware.

  • 'jni/VideoData*.*' - Support files for data type use by DDS. Generated with "rtiddsgen VideoDemo.idl" using rtiddsgen distributed with RTI Connext DDS.

  • 'jni/', 'jni/' - Defines the build process and external libraries needed by the native code (RTI Connext DDS and GStreamer) supporting the demo.

  • 'VideoData.idl' - Defines the data structure used by DDS to stream video frames over a network.

Android Application Files

  • 'AndroidManifest.xml' - Main definition file for rtivideodemo-android app including which Activity to start on startup.

  • 'res/layout/activity_main.xml' - Main layout of the graphics elements of the application. Open this file to modify the graphical elements of the application.

  • 'res/layout/preferences_with_value.xml' - Utility used to define a layout where the current value of a preference are displayed on the same line as the preference.

  • 'res/menu/menu.xml' - Defines the layout of the Android options menu.

  • 'res/xml/settings.xml' - Defines the preferences that can be set by the Settings option submen.