Both technologies are now an integral part of Android 9
Android Pie comes with a string of major upgrades in terms of audio playback, since the Extended High-Efficiency AAC (xHE- AAC) audio codec and MPEG-D DRC Loudness and Dynamic Range metadata, both substantially developed by Fraunhofer IIS, are mandatory components of the operating system. The xHE-AAC implementation used by default in Android Pie has been provided by Fraunhofer IIS and is available as part of the FDK2 AAC Codec Library for Android.
Service providers and app developers that want to use xHE-AAC to distribute content can contact Fraunhofer to get access to professional xHE-AAC encoder software or work with one of our streaming equipment partners, such as Modulation Index or Telos. A technical white paper on xHE-AAC and MPEG-D DRC explaining the major use cases, benefits and engineering details is available online.
The advanced features of xHE-AAC enable video and audio streaming providers worldwide to offer an enhanced, more reliable consumer experience. The codec can deliver transparent quality for customers on a good network connection and can also seamlessly shift to the bit rates supported by a congested network while on the go. This is particularly of interest to streaming providers active in emerging markets where consumers still rely on 2G or 3G connections.
xHE-AAC – a fourth-generation codec and the youngest member of the MPEG-AAC audio codec family – expands the spectrum of usable stereo data rates, which now ranges from 12 kbit/s up to 500 kbit/s or higher. xHE-AAC was developed specifically for adaptive streaming; alongside MPEG-H Audio, it is the only codec that switches seamlessly between the available data rates and quality levels. The audio bit rates required have been reduced by up to 50 percent compared to the predecessor HE-AAC codec. This frees up data capacity, which can be used to improve the video quality.
In addition, MPEG-D DRC – Loudness and Dynamic Range Control – provides mandatory loudness control for xHE-AAC to play back content at a consistent volume and offers dynamic range control processing to provide the best possible user experience for listening on any platform and in any environment.