Technology Blog: MainConcept

xHE-AAC: A New Standard for the Audio & Video Streaming Experience

Written by Frank Schönberger | Aug 3, 2021

When people talk about Adaptive BitRate (ABR) streaming, the focus is usually on video with reference to quality and bandwidth, while audio typically plays only a minor role or is entirely neglected. It’s true that video takes up considerably more bandwidth than audio, but for most production, high-quality audio is anything but an afterthought. The common audio standard currently used is AAC—developed by the Fraunhofer Institute for Integrated Circuits (IIS) and others—which is natively supported by almost all mobile devices, tablets, Smart TVs, desktop PCs and browsers. Fraunhofer recently released AAC’s successor, xHE-AAC™, which has already been deployed on countless Android and iOS devices. Even Netflix has identified xHE-AAC as the key audio format to deliver an unrivaled audio experience to their audience. 

The benefits of xHE-AAC

The team at Fraunhofer IIS addressed the pain points of today’s streaming users, content creators and service providers when they developed xHE-AAC. This new and flexible format helps to significantly reduce audio bandwidth constraints where network conditions are limited. This might affect different streaming markets ranging from OTT and broadcast to education and virtual meetings/conferences. The seamless switching between various quality levels and audio bitrates makes xHE-AAC more flexible than its predecessor, the legacy AAC formats. The integrated Loudness and DRC processing creates an optimized playback experience even in noisy or other environments where it is difficult to hear, preserving excellent audio quality while keeping the bitrates low.

Although the audio bitrates are often neglected when it comes to bandwidth savings, xHE-AAC uses a unique approach: The audio bandwidth you save with low bitrate xHE-AAC can be used for improving the overall video quality. This saved bandwidth can often make certain areas or textures within a picture clearly visible and distinguishable again. After all, every bit counts!

What sets the xHE-AA codec apart?

The new codec not only supports xHE-AAC but also the legacy AAC formats: AAC-LC (AAC - Low Complexity), HE-AAC v1 and HE-AAC v2 (High Efficiency - AAC) bitstreams. The encoder creates the full AAC portfolio, and the decoder plays it back. This enables full backward compatibility for existing software and hardware products.  The xHE-AAC format delivers impressive audio at bitrates as low as 12 kbit/sec for stereo all the way up to 500 kbit/sec for crystal clear audio quality. A mandatory feature for xHE-AAC is Loudness Metadata processing and Dynamic Range Control (DRC), which helps to create an unrivaled listening experience. It does so by adapting the audio content’s characteristics to the actual user environment when playing back the footage. The Loudness as well as DRC Metadata processing is mandatory for xHE-AAC. The xHE-AAC format will lift the user’s audio experience to the next level—even under low bandwidth conditions!

Regardless of whether you are targeting speech, music or even mixed content, Fraunhofer xHE-AAC provides exceptional audio quality at extremely low bitrates.

Webinar and beta program for xHE-AAC

By collaborating with the Fraunhofer IIS team, we have extended our highly acclaimed FFmpeg product line, adding the beta MainConcept xHE-AAC Encoder Plugin for FFmpeg. Please join us live for our August 18 webinar to learn about the new xHE-AAC FFmpeg plugin. Experts from Fraunhofer and MainConcept will discuss how:

  • Loudness and dynamic range metadata in xHE-AAC can help you optimize the dynamic range and loudness level of a program to provide the best possible listening experience on any device and in any environment
  • xHE-AAC empowers service providers and audio professionals worldwide with high-fidelity FFmpeg-based ingest and encoding frameworks
  • Audio bandwidth is saved as a result of xHE-AAC’s efficiency without sacrificing quality
  • To maximize audio encoding efficiency from 12 kbit/s to 500 kbit/s and above for optimized stereo services

Register now to watch live or on demand after the event.

If you want to be an early adopter of this exciting audio format and get your hands on the MainConcept xHE-AAC Encoder Plugin for FFmpeg, apply now for our Beta Program and be a part of testing this emerging audio experience!

xHE-AAC™ is a registered trademark of Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. in Germany and other countries.