Audio Framework


The Ref-OS-IoT uses the Advanced Linux Sound Architecture (ALSA) framework to deliver Audio features to application.

See for more information.

Audio Software Stack

Audio Software Architecture shown below outlines the OS audio Stack which covers the following aspects:

  • Application uses GStreamer to setup the Audio pipeline.
  • GStreamer provides ALSA sink and source used on the pipeline
  • GStreamer good and bad audio codecs are used as filters in the audio pipeline.
  • ALSA library provides a transparent access to audio driver to play and record audio


Pulse Audio Features

PulseAudio is a networked sound server for advanced audio features such as:

  • Software mixing of multiple audio streams, bypassing any restrictions the hardware has.
  • Sample rate conversion of audio streams
  • Network transparency, allowing an application to play back or record audio on a different machine than the one it is running on.
  • Sound API abstraction, alleviating the need for multiple back-ends in applications to handle the wide diversity of sound systems out there.
  • Generic hardware abstraction, giving the possibility of doing things like individual volumes per application.
  • PulseAudio comes with many plugin modules.


GStreamer plugins can be found at:

Hardware Codec Connection

The Intel® Joule™ developer kit does not include a hardware audio codec. A reference connection is provided in Audio Interface topic in the Expansion Board Design Guide section.

For more complete information about compiler optimizations, see our Optimization Notice.