I stand corrected...
Thank you very much, this was "quite" a helpful answer!
Stefan
----- Mensagem de Dylan Marcus <dy...@mach1.tech> ---------
Data: Tue, 4 Jan 2022 14:49:43 -0500
De: Dylan Marcus <dy...@mach1.tech>
Assunto: Re: [Sursound] Ambisonics with AirPods head tracking
Para: Surround Sound discussion group <sursound@music.vt.edu>
On Jan 4, 2022, at 2:39 PM, Stefan Schreiber <st...@mail.telepac.pt> wrote:
In other words:
Is there a way to get access to the orientation data of the Airpods?
And in which format are these? Cardan angles? (yaw, pitch, roll)
Quaternions?
“Is there a simple process for listening to FOA Ambisonic recordings on
AirPods, with head tracking?”
The question is of course of general interest.
I suppose that Apple currently does not give some easy access to
the iPod 3DoF orientation data. But actually, why not?
They actually do via the CMHeadphoneMotionManager API
Here is an example app we made when this was introduced:
https://github.com/Mach1Studios/M1-AirPodOSC
<https://github.com/Mach1Studios/M1-AirPodOSC>
This app just shows how to access the orientation and send it to
any host via OSC, feel free to use and fork however you like.
We also have some iOS examples of this being applied to spatial
audio playback via our SDK:
https://github.com/Mach1Studios/Pod-Mach1SpatialAPI
<https://github.com/Mach1Studios/Pod-Mach1SpatialAPI>
You could even modify our “mach1-transcode-example” to playback FOA
(transcoding to our Mach1 Spatial vector channel based format and
using Mach1Decode to play it back).
https://github.com/Mach1Studios/Pod-Mach1SpatialAPI/tree/master/Examples/mach1-transcode-example/mach1-transcode-example
<https://github.com/Mach1Studios/Pod-Mach1SpatialAPI/tree/master/Examples/mach1-transcode-example/mach1-transcode-example>
——
When it comes to using the orientation from AirPods, we are happy
with the performance and access via the CMHeadphoneMotionManager,
however this is limited when distributing an app that uses it (read
below). As it comes to how the orientation is used in “Apple’s
Spatial Audio” we are EXTREMELY unhappy, you can read about that in
detail here:
https://research.mach1.tech/posts/feedback-on-apple-spatial-audio/
<https://research.mach1.tech/posts/feedback-on-apple-spatial-audio/>
And
https://research.mach1.tech/posts/observations-and-limitations-of-apple-spatial-playback-implementation/
<https://research.mach1.tech/posts/observations-and-limitations-of-apple-spatial-playback-implementation/>
It should be noted that we have been doing tests of creating open
source example codebases to allow artists/labels distribute spatial
music via an iOS app until common music services support more
spatial audio playback. We have been met with a lot of pushback from
Apple which we have been tracking here:
https://research.mach1.tech/posts/submitting-spatial-music-apps-to-ios-app-store/
<https://research.mach1.tech/posts/submitting-spatial-music-apps-to-ios-app-store/>
- - - -
Best,
Stefan
P.S.: It is of course possible (and very likely “utterly legal”)
to hack this device. Because you have bought it. (Otherwise Apple
would pretend that some headtracker sensor functions of their
head-/earphones would be “copy-protected”, or alike. This seems to
be a nonsense idea, right from the start. Trade secrets? But why
are you then selling a product in the first place? It is your
risc if < your > customer discovers how your product is
functioning, even outside the limited world of iOS...
So I suppose the Airpods should send some position data over the
BT5 interface, from time to time. So you have to check the data
coming from the AirPods, not from the iPhone/iPad. Are any talented
"makers" lurking on this list? )
P.S. 2: What is pretty clear is that Apple < does not tell you >
how to read out some headtracking sensor data.
A different story is to get access to the position/orientation
data of an iPhone/iPad itself, which should be supported by the OS.
(Don’t check this now.
For Android:
https://developer.android.com/guide/topics/sensors/sensors_position
)
----- Mensagem de Hugh Pyle <hp...@cabezal.com> ---------
Data: Tue, 4 Jan 2022 08:19:42 -0500
De: Hugh Pyle <hp...@cabezal.com>
Assunto: [Sursound] Ambisonics with AirPods head tracking
Para: Surround Sound discussion group <sursound@music.vt.edu>
Hi sursounders,
I've been away from the Apple audio ecosystem for a long while. But now I
have some Airpods, and their head-tracked / spatialization functions are
interesting.
Is there a simple process for listening to FOA Ambisonic recordings on
AirPods, with head tracking? I have a number of recordings from TetraMic
and H3-VR that I'd like to render for immersive headphone playback, with
head-tracked rotation. Ideally an audio-only production workflow that
doesn't involve expensive proprietary tools. But it's OK if the best
answer involves publishing to YouTube or embedding the Ambisonic stream in
some other video format.
Thanks for any suggestions -
Hugh
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