API changes

New callback classes

Added new classes AudioStreamDataCallback and AudioStreamErrorCallback. These classes replace AudioStreamCallback which is now deprecated. The new callback classes separate the responsibilities of data handling and error handling.

Additionally, AudioStreamErrorCallback includes a new onError method. This allows you to override the default error handling and stop/close the audio stream yourself. More details.

New features

• Channel count conversion. Oboe now includes a ChannelCountConverter. This is part of the flowgraph library. It can be used directly for performing channel count conversion. Internally this class is used to handle situations where opening a stream with a specific channel count results in suboptimal performance. For example, some devices cannot obtain a low latency mono input stream so Oboe opens the stream in stereo and performs a seamless stereo->mono conversion for the application. [commit, PR]
• Set a minimum buffer size for LatencyTuner. Added method LatencyTuner::setMinimumBufferSize which allows you to set the minimum buffer size in frames. This stops the LatencyTuner from reducing the buffer size below a user-defined threshold. Note that the value specified for the minimum buffer size should be an integer multiple of the burst size. [PR]

Bug fixes / workarounds

• If you attempt to open an AAudio input stream without the relevant permission Oboe will now output a more useful error message. [commit]
• Fixed a race condition that could cause a crash during close() if a callback was still running. [PR]
• Fixed an issue with the sample rate converter which could cause input streams using callbacks to stall. [issue, commit]
• Fixed several crashes associated with using setFramesPerCallback. [commit]
• Fixed a bug that could cause stop() of an OpenSL ES stream with a non-zero timeout value to spin forever. [original issue]
• In cases where the VoicePerformance input preset is not supported (OpenSL ES and Android P and below) Oboe will use the VoiceRecognition preset instead. [commit, commit]
• In Android RQ1A a regression was introduced which meant that when a stream disconnects (e.g. headphones unplugged) a TIMEOUT error code was supplied rather than the expected DISCONNECT. This only affects SHARED AAudio MMAP streams. Oboe works around this by returning a DISCONNECT error code if a TIMEOUT error code is received on RQ1A. [commit]
• Fixed a potential race condition when closing an OpenSL ES stream. [PR]
• Fixed a problem where AAudio might accidentally call the flowgraph units in Oboe instead of in AAudio. [PR]
• Added a workaround for broken mono recording on Samsung S9. [PR]

Documentation and samples updates

• [docs] Added the OpenSL ES migration guide.
• [all samples] Standardise package name to com.google.oboe.samples
• [hello-oboe] Save user settings, use shared stream, use locks to prevent race conditions [commit]
• [RhythmGame] Updates to the FFmpeg extractor and decoder [commit, commit]
• [DrumThumper] Audio is resampled on app load to avoid resampling penalty during playback [commit]
• [DrumThumper] App is now published on Play Store.
• [parselib] Fixed a problem with parsing unexpected chunks in a WAV file. [issue]
• [OboeTester] can now print a device and microphone report.

All commits since 1.4.3: 1.4.3...1.5.0

How to update existing code

On previous version of Oboe you implement AudioStreamCallback and override onAudioReady for data handling and the onError* methods for error handling.

In Oboe 1.5 data callbacks and error callbacks have been split into 2 separate classes. To migrate your code, create an AudioStreamDataCallback and an AudioStreamErrorCallback. Then copy the code from your existing AudioStreamCallback implementation to the new methods, as per the following table:

Corresponding setDataCallback and setErrorCallback methods have been added to AudioStreamBuilder and you must use these in place of setCallback.

The term "callback" within Oboe is now ambiguous so the following methods have been renamed to refer specifically to the data callback. If you're using any *FramesPerCallback methods, you should use the new methods instead.

For further guidance take a look at this PR which updates the Oboe sample code.