Netflix as a streaming service supports all popular audio and video formats, be it HDR and Dolby Vision for an immersive viewing experience or Dolby Atmos and 5.1 surround sound for the audio. Now it looks like Netflix is looking at enhancing the audio experience on Android devices as it now streams using xHE-AAC on Android devices.
Yes! So don’t be surprised if Netflix sounds nicer the next time you marathon a show on your Android phone. Netflix has upgraded its Android app to stream audio in xHE-AAC (Extended HE-AAC with MPEG-D DRC; yes, it’s a mouthful), promising “studio-quality” sound that’s also more consistent — that is, you should enjoy it in more places.
The company has announced that sound on this platform will now be streamed in the xHE-AAC codec on devices running Android 9 or above.
“Netflix now streams Extended HE-AAC with MPEG-D DRC (xHE-AAC) to compatible Android Mobile devices (Android 9 and newer). With its capability to improve intelligibility in noisy environments, adapt to variable cellular connections, and scale to studio-quality, xHE-AAC will be a sonic delight to members who stream on these devices”.
The codec allows for higher fidelity audio through enhanced loudness management with the Enhanced HE-AAC codec and MPEG D DRC (Dynamic Range Control). Netflix explained that these features were necessary for playback scenarios in which the large dynamic range of a TV show or movie is undesirable or even impossible – such as when low-fidelity earbuds or mobile device speakers are used, or users are watching content in noisy environments.
“If the dynamic range of a member’s device and environment is less than the dynamic range of the content, then they will not hear all of the details in the soundtrack. Or they might frequently adjust the volume during the show, turning up the soft sections, and then turning it back down when things get loud. In extreme cases, they may have difficulty understanding the dialogue, even with the volume turned all the way up.”
DRC employs a sophisticated algorithm and metadata to boost softer sounds according to multiple situation-based profiles or by scaling gains. The best part about the new xHE-AAC is that it is scalable. Which means that it will offer the higher fidelity audio when your connection is good and scale back the audio when you are on a weaker connection.
There is also Loudness management which as the name suggests prevents the volume from going extremely loud. This also helps with listening to content over the phone’s speaker adjusting the volume so that the dialogue is easily audible and the action sequences don’t make the phone’s volume explode. This should help with understanding dialogues in an action movie without worrying about the explosions getting too loud.
To take advantage of xHE-AAC users will need to be on smartphones running on Android 9 or later OS. You’ll need at least Android 9 Pie to use xHE-AAC. While this isn’t quite as useful as it could be when you’re likely watching at home during the pandemic, it could be important if you’re determined to finish a show in bed. If nothing else, it could save you from reaching for your earbuds in noisier environments.
The difference
Netflix provided two graphs that illustrate how DRC enhances the listening experience in a given environment which contained a large amount of background noise. The first graph illustrates a situation in which it impossible to hear softer details below -40dBFS even when an elevated output level of -16dBFS is used for dialogue, indicated by the bold black lines.
The second figure shows the impact of adding DRC, which boosts softer sounds without changing the dialogue volume level, making them audible without requiring the user to change the volume.
Adaptive audio bitrate
In addition, xHE-AAC adds adaptive bitrate support to Android mobile devices, a feature which was previously launched on Netflix’s TV-based app. This allows the audio quality to be automatically adjusted according to the strength of the network that is being used to stream the content. The result is that buffering is minimized when the connection speed is slow while studio-quality sound can be delivered when the network is strong.
