The audio codec of choice for adaptive audio and video streaming and digital radio

At a glance


  • Latest generation of the AAC codec family
  • Single codec for all content types including:
    • Audio for Video Services
    • Music
    • Audiobooks
    • Podcasts
  • Improved quality at stereo bit rates of 12 to 500 kbit/s or above
  • Allows adaptive streaming through MPEG-DASH or HLS
  • Seamless transitions between bit rates when network conditions deteriorate or improve
  • MPEG-D DRC provides mandatory loudness and dynamic range control for consistent playback loudness of live and file-based content.
  • Natively supported in the latest Apple, Android, Amazon and Microsoft operating systems and products
  • xHE-AAC encoder with a Live Automatic Loudness feature for live inputs (such as streaming of concerts, sports events or news streams) 
  • Licensed to Meta, Microsoft and Netflix
  • Included in the AAC Patent Licensing Program by Via Licensing Alliance at no extra cost
xHE-AAC logo
xHE-AAC is a registered trademark of Fraunhofer in Germany and other countries.


xHE-AAC-streaming services sound better than ever, even at low bit rates.
Provide subscribers with more minutes of your streaming service at the same data plan - thanks to the efficiency of xHE-AAC.
© Fraunhofer IIS
Bit rate transition scenario with xHE-AAC.

xHE-AAC (the combination of Extended HE-AAC and MPEG-D DRC), primarily developed by Fraunhofer IIS and the latest addition to the MPEG AAC codec family, bridges the gap between speech and audio coding. It provides consistently high-quality audio for all signal types, such as speech, music or mixed content, at all bit rates – starting as low as 6 kbit/s for mono and 12 kbit/s for stereo services, up to 500 kbit/s and above. This makes xHE-AAC the audio codec of choice for digital radio and adaptive streaming applications. It is a mandatory audio codec in Digital Radio Mondiale (DRM) and in Google's Android Pie operating system; the FDK2 implementation including xHE-AAC is provided by Fraunhofer and is available here.


Adaptive Streaming

xHE-AAC was inherently designed for adaptive streaming: its bit rate flexibility enables MPEG-DASH or HLS streaming apps and streaming radio players to switch to very low bit rate streams and offer continuous playback even under challenging network conditions. When network connectivity recovers, the xHE-AAC player will adapt to a higher bit rate and seamlessly switch over the full range of bit rates, up to transparent quality. Additionally, the outstanding coding efficiency of xHE-AAC means the bit rate saving can be invested in improving the video quality of mobile video streaming.


Loudness and Dynamic Range Control

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.


Compatibility of xHE-AAC

xHE-AAC profile decoders are capable of decoding all AAC versions including AAC-LC, HE-AAC and HE-AACv2. It is easy to integrate xHE-AAC streams into existing encoding workflows by supplementing legacy higher bit rate streams.


An uninterrupted streaming service with good audio quality even in 2G networks is now possible thanks to xHE-AAC.
With xHE-AAC, your DRM service sounds better than ever before, even at very low bit rates.

With its special features, xHE-AAC effortlessly meets the requirements of digital radio and mobile audio and video streaming applications, where various audio content types need to be transmitted at very low bit rates.


xHE-AAC for streaming applications  

The codec opens up the possibility of reaching billions of users in emerging markets where 2G/3G networks still exist in significant numbers and wherever heavily congested 4G/5G networks in major cities are a common reality. Streaming service providers benefit from drastically reduced CDN cost and simplified encoding asset management; consumers enjoy improved service quality while saving on their precious monthly data allowance.


xHE-AAC for live streaming

For the encoding of live broadcasts and events with xHE-AAC, our encoder is equipped with the Live Automatic Loudness feature. This offers a fully automatic, unattended loudness control for live signals, while preserving much of the signal’s dynamic range and loudness transients. Live content will be played by an xHE-AAC decoder at a loudness level consistent with other xHE-AAC content. As the feature is completely integrated with the xHE-AAC encoder, there are no user adjustments required.



DRM (Digital Radio Mondiale) is the first digital radio standard to adopt xHE-AAC (mandatory since 2013) and benefit from its features. As xHE-AAC is a superset of the MPEG HE‑AAC codec used for all DRM transmissions to date, HE‑AAC remains available as part of the DRM standard to retain compatibility with existing systems. With xHE-AAC, DRM broadcasters can now use the same codec for all types of content and benefit from a simplified codec configuration process: The encoder automatically optimizes all quality-relevant parameters, eliminating the need to change configuration settings depending on the type of audio content being broadcast. In addition, the reduced bit demand of the codec allows for the delivery of a wider selection of audio programs.  


Codec implementations of xHE-AAC for use in DRM and streaming applications are available for the following platforms:

  • PC (Windows/Mac OS X/Linux)
  • ARM (decoder only)
  • MIPS (decoder only)
  • Texas Instruments C6x, DaVinci, OMAP (decoder only)
  • ADI Sharc+ (decoder only)
  • Cadence Xtensa (decoder only)
  • Apple iOS® SDK (decoder only)
  • Apple iOS 13 (decoder only)
  • Fire OS 7 (decoder only)
  • Android™ (decoder included in Android 9 and later)

DRM broadcast encoder solutions based on Fraunhofer’s ContentServer technology, as well as third-party implementations, already support xHE-AAC. All DRM receiver chipsets belonging to the initial mass-market generation include xHE-AAC from market launch.

Further information about our development and design kits can be found on our "Platforms" page.

Software licensing

If you are interested in licensing software from us, please fill out the request form below.

Patent licensing

xHE-AAC is part of the AAC patent pool licensing program administered by Via Licensing Alliance. Please visit https://www.via-la.com/ for more information or contact contracts@via-la.com.

xHE-AAC is a registered trademark of Fraunhofer in Germany, the United States and other countries.

Our partners' products and services

Here you can browse a selection of recently-launched products and services that support xHE-AAC.

Request licensing information: xHE-AAC

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