AudioStreamer

The AudioStreamer is a cross-platform audio streaming player for iOS and Android that uses Djinni and CMake to create a consistent high-level interface for wrapping the platform-specific proxy implementations.

In the Mobile C++ video series this serves as the primary bidirectional example. In this instance we're using Djinni to call platform specific implementations of the audio player, which is then accessible through the AudioStreamer (or MCPAudioStreamer on iOS) class's singleton reference.

Build Instructions

To build the AudioStreamer library for iOS and Android follow the instructions below to generate the appropriate AudioStreamer.framework (iOS) or proper Android Studio CMake integration (Android). The CMakeLists.txt file should take care of generating the libraries and handling all internal linking of the sub-dependencies (such as djinni)

Requirements

• A Mac computer (Windows instructions will come shortly)
• A version of the Java JDK must be installed for djinni to run properly
• CMake
  • Specifically remember to install CMake to use in the Command Line once you've downloaded and installed the CMake app in your applications directory. You can do this using this command in the terminal:

  sudo "/Applications/CMake.app/Contents/bin/cmake-gui" --install
  

• A valid "iPhone Developer" code signing identity - this is super important because compiling the iOS and OSX frameworks must be codesigned.
• If you've never built a project with Xcode be sure to run an empty project at least once with your codesigning team enabled to prompt the "Enable Developer Mode" window. Once you enable this xcodebuild will be able to find your iPhone Development certificate.

Cloning the repo

You're going to want to clone this repo recursively to get the submodules for djinni and polly (we're using custom forks from the Mobile C++ organization)

git clone --recursive https://github.com/mobilecpp/audio-streamer.git

If you've already cloned the repo then you can update the submodules like so:

git submodule update --init --recursive

iOS

There's a helper script to build a universal AudioStreamer.framework that can be used for all the valid device and simulator architectures (x86_64 i386 armv7 armv7s arm64).

cd scripts && ./build_ios.sh

Requirements

• CMake 3.1 (minimum)
• Xcode 8
• iOS 10.2
• macOS 10.12

Once successfully built the universal AudioStreamer.framework and libdjinni.a library will be available in the libs folder under the target device (iOS or macos). From this point the two can simply be dragged and dropped into a project or added by reference.

Notes

Ensure the AudioStreamer.framework for iOS or macOS is in the Embedded Binaries.

Additionally, if you aren't copying the AudioStreamer.framework and libdjinni.a library into your project then you're going to need to modify the Search Paths in the Build Settings to set the framework and library search paths to the libs/ios or lib/macos output directory. Note: You only need to do this if you're adding the AudioStreamer.framework and libdjinni.a library by reference and not copying it into your app.

Alternatively, you can just run the CMakeLists.txt to generate a AudioStreamer.framework target for whatever toolchain you'd like to compile against.

macOS

In a similar fashion as iOS, a macOS framework can also be built. Check out the build_macos.sh script to see how we can also compile the AudioStreamer.framework for macOS.

cd scripts && ./build_macos.sh

Android

For Android all you need to do is simply copy or add this repo as a submodule to your existing Android Studio project. There are, however, a couple things to note.

Requirements

• Android Studio 2.3 or later
• Project must have C++ support enabled (checkmark when you're creating the project)
• You must enable C++11 instead of the default toolchain
• Enable exception and rtti

Notes

Ensure in your AndroidManifest.xml you've added the user permissino for internet like so:

<uses-permission android:name="android.permission.INTERNET" />

In the bottom example we made a folder called deps and recursively cloned the audio-streamer repo into it as a submodule.

git submodule add https://github.com/mobilecpp/audio-streamer.git audio-streamer
git submodule update --init --recursive

Go into the audio-streamer folder and run the djinni script.

cd deps/audio-streamer
cd scripts && ./run_djinni.sh

Next go into your app's build.gradle file and add the java source sets from the audio-streamer. If you have placed the audio-streamer folder in a different location than your app's deps folder like above then you should modify the paths below to reflect your project's structure.

Once this is complete you will need to resync gradle. Afterwards, you should see the java classes from the AudioStreamer in your project:

In the top menu go to Build and click Refresh Linked C++ Projects. You should now see the libraries in the cpp folder and additional CMakeLists.txt files in the External Build Files section of the project pane.

Next, we actually load the library into the MainActivity (or another other activity that will actually use this class) by adding the following to the top of the class.

static {
    System.loadLibrary("AudioStreamer");
}

See the Android sample in the examples folder to see how to use another path structure incase you'd like to keep the audio-streamer folder in a different location.