Getting Started

The easiest way to start using Oboe is to build it from source by adding a few steps to an existing Android Studio project.

Adding Oboe to your project

1. Clone the github repository

Start by cloning the Oboe repository:

git clone https://github.com/google/oboe

Make a note of the path which you cloned oboe into - you will need it shortly

2. Update CMakeLists.txt

Open your app's CMakeLists.txt. This can be found under External Build Files in the Android project view.

CMakeLists.txt location in Android Studio

Now add the following commands to the end of CMakeLists.txt. Remember to update **PATH TO OBOE** with your local Oboe path from the previous step:

# Set the path to the Oboe directory.
set (OBOE_DIR ***PATH TO OBOE***) 

# Add the Oboe library as a subdirectory in your project.
add_subdirectory (${OBOE_DIR} ./oboe) 

# Specify the path to the Oboe header files.
include_directories (${OBOE_DIR}/include)

In the same file find the target_link_libraries command. Add oboe to the list of libraries which your app's library depends on. For example:

target_link_libraries(native-lib oboe)

Here's a complete example CMakeLists.txt file:

cmake_minimum_required(VERSION 3.4.1)

# Build the Oboe library
set (OBOE_DIR ../../../oboe)  
add_subdirectory (${OBOE_DIR} ./oboe) 
include_directories (${OBOE_DIR}/include)

# Build our own native library
add_library (native-lib SHARED src/main/cpp/native-lib.cpp )

# Specify the libraries which our native library is dependent on
target_link_libraries (native-lib log oboe)

Verify that your project builds correctly. If you have any issues building please report them here.

Using Oboe

Once you've added Oboe to your project you can start using Oboe's features. The simplest, and probably most common thing you'll do in Oboe is to create an audio stream.

Creating an audio stream

Include the Oboe header:

#include <oboe/Oboe.h>

Streams are built using an AudioStreamBuilder. Create one like this:

oboe::AudioStreamBuilder builder;

Use the builder's set methods to set properties on the stream (you can read more about these properties in the full guide):

builder.setDirection(oboe::Direction::Output);
builder.setPerformanceMode(oboe::PerformanceMode::LowLatency);
builder.setSharingMode(oboe::SharingMode::Exclusive);

Define an AudioStreamCallback class to receive callbacks whenever the stream requires new data.

class MyCallback : public oboe::AudioStreamCallback {
public:
    oboe::Result
    onAudioReady(oboe::AudioStream *audioStream, void *audioData, int32_t numFrames){
        generateSineWave(static_cast<float *>(audioData), numFrames);
        return oboe::DataCallbackResult::Continue;
    }
};

Supply this callback class to the builder:

MyCallback myCallback;
builder.setCallback(&myCallback);

Open the stream:

oboe::AudioStream *stream;
oboe::Result result = builder.openStream(&stream);

Check the result to make sure the stream was opened successfully. Oboe has a convenience method for converting its types into human-readable strings called oboe::convertToText:

if (result != Result::OK){
    LOGE("Failed to create stream. Error: %s", oboe::convertToText(result));
}

Note that this sample code uses the logging macros from here.

Check the properties of the created stream. The format is one property which you should check. The default is float on API 21+ and int16_t on API 20 or lower. This will dictate the audioData type in the AudioStreamCallback::onAudioReady callback.

oboe::AudioFormat format = stream->getFormat();
LOGI("AudioStream format is %s", oboe::convertToText(format));

Now start the stream.

stream->requestStart();

At this point you should start receiving callbacks.

When you are done with the stream you should close it:

stream->close();