Delivering an immersive sound expertise with Spatial Audio

Posted by Nevin Mital – Developer Relations Engineer, Android Media

In Android 13 (API stage 33), we launched a brand new standardized platform structure for spatial audio, a premium and extra participating sound expertise. With spatial audio, your content material sounds extra sensible to customers by making it sound as if they’re in the course of the motion. The person devices from a band may be separated and “positioned” across the consumer, or the sound from a whale would possibly develop because it approaches from behind and taper off because it swims away. Learn on to study extra about Android’s assist for spatial audio and the best way to implement the function in your app.

There are two primary distinctions of spatial audio:

• With static spatial audio, the sounds are anchored to the consumer and transfer with them. A hen chirping to their left will all the time be on their left, irrespective of how they flip or transfer their head.

• With spatial audio with head monitoring, the sounds are positioned within the atmosphere across the consumer. By turning their head to the left, the consumer will now hear the hen chirping in entrance of them.

On Android, solely multi-channel audio configured with the appropriate AudioAttributes and AudioFormat is spatialized by default, although OEMs can customise this conduct. On units the place the OEM has built-in a spatializer impact, static spatial audio will work when any headset is related to the machine, although head-tracked spatial audio requires a headset with appropriate head monitoring sensors. OEMs like Pixel, OnePlus, and Xiaomi have already made these experiences accessible to their customers.

The best method to combine with this function is to make use of ExoPlayer! If you happen to use ExoPlayer from Jetpack Media3 launch 1.0.0 or newer, ExoPlayer will configure the decoder to forestall multi-channel audio from being downmixed to stereo and the default monitor choice conduct will take note of whether or not or not spatialization is feasible. This implies your content material simply wants to incorporate a multi-channel audio monitor that ExoPlayer can choose. ExoPlayer will monitor the machine’s state and choose a multi-channel monitor when spatialization is feasible, or swap to a stereo monitor if not.

Android 12L (API stage 32) added the brand new Spatializer class to permit you to question the spatialization capabilities of the machine. There are 4 situations that should all be true for the machine to output spatialized audio:

ExoPlayer performs these checks when deciding which audio monitor to pick. To additional verify if head monitoring is offered, you may name the isHeadTrackerAvailable() methodology. The Spatializer class additionally contains the next listeners to have the ability to react to adjustments within the machine’s state:

With these alerts, you may manually modify your playback for spatial audio. Observe that in case you are not utilizing ExoPlayer, you need to be certain to configure the decoder to output multi-channel audio when potential by setting the max channel depend to a big quantity with MediaFormat.setInteger(MediaFormat.KEY_MAX_OUTPUT_CHANNEL_COUNT, ##). See how ExoPlayer does this on GitHub. There are two methods to forestall spatialization relying in your use-case. In case your audio is already spatialized, name setIsContentSpatialized(true) when configuring the AudioAttributes on your audio stream to forestall the audio from being double-processed. In all different instances, you may as an alternative name setSpatializationBehavior(AudioAttributes.SPATIALIZATION_BEHAVIOR_NEVER) to disable spatialization altogether.

As talked about beforehand, utilizing spatial audio requires a supported machine (that’s, getImmersiveAudioLevel() does not return SPATIALIZER_IMMERSIVE_LEVEL_NONE) and a related headset. To check spatial audio, begin by ensuring the function is enabled in settings:

• For wired headsets, go to System settings > Sound & vibration > Spatial audio.
• For wi-fi headsets, go to System settings > Linked units > Gear icon on your wi-fi machine > Spatial audio.

Observe that for spatial audio with head monitoring, the headset will need to have head monitoring sensors which might be appropriate with the machine, reminiscent of Pixel Buds Professional with a Pixel telephone, and head monitoring should even be enabled in settings.

Listening to is believing, so we extremely advocate making an attempt out spatial audio for your self! You may see an instance implementation in our pattern app, Common Android Music Participant. And for extra particulars on all the pieces mentioned right here, take a look at our spatial audio developer information.