Usage?

[ThreeDeeJay]

I installed this module and found the option in Settings, but I'm not sure how to actually use it.
Does it support virtualizing the surround output of apps like Kodi or does it only work with object-based audio like Dolby Atmos?
And does it require proprietary/Google apps or does it also work with any app that allows letting the system decode the audio?
I tried enabling it for both wired and bluetooth headphones and I only hear a pop while switching but the audio doesn't actually change, though I only tried some surround files in Kodi and Musicolet. Not sure what apps and spatial audio formats are supported.

[ThreeDeeJay]

By the way, I should probably mention that I got this while installing the module:

Limited spatial audio support found

More details:

• Magisk v30.4
• ROM: lineage-22.2-20251007-nightly-pdx215-signed.zip
• Android 15
• Sony Xperia 1 III

[ThreeDeeJay]

I just found an app to test it and compiled it here:
https://github.com/ThreeDeeJay/SpatialAudio-HeadTracker-Test/releases

Too bad my headphones don't have headtracking so I can't test orientation, I just hear a tone fixed to my right and it doesn't even seem to use HRTF.

Anyhow, it seems it can virtualize channel-based audio tracks

but I tried loading this 7.1.4 WAV in Just Player and Fermata both of which use ExoPlayer, but neither seem to spatialize the file. I guess the player has to explicitly request spatialization?

I know there's sView which can even use the phone's gyroscope for "headtracking" and OpenAL Soft which has arguably the best HRTF/spatialization, but I'd really like to be able to virtualize the surround audio track from video streaming apps or plugins for Kodi, or local 5.1 music files. So besides sView, I've mostly just been using upmix+virtualization via Viper4Android like this: https://youtu.be/NlX3na3O4IE

[akavkl]

Any app that outputs multi-channel to OS gets downmixed without HRTF if limited support is found or downmix with HRTF if full support is found.
My headphones don't have head tracking built-in so I can't test that.

[ThreeDeeJay]

I see. So what would be needed to get full support for HRTF downmix? Headtracking?
That'd be a really arbitrary limitation because virtual surround works reasonably well in other apps even without headtracking, especially with an HRTF that matches our ears. Plus it wouldn't really make a lot of sense in 2D content that isn't meant to be rotated with the sound field, unlike 360/VR videos, which often use ambisonics instead of surround anyway. 🤔

[akavkl]

Audio HAL 7.1 is required for Google's spatial audio implementation to work with HRTF and that needs to be build with the ROM itself.

[ThreeDeeJay]

I see. Any idea how it could be added to LineageOS?
Or perhaps like an addon flashable after the ROM like GApps?

I wonder how come spatial audio isn't already built into AOSP and LineageOS to begin with, since I've been hearing about it since like Android 13. 😔