Reestablishing Guest Bluetooth after Bluetooth Disconnect

[RobertJ234]

VirtualBox Version: 7.08
Guest Edition Version: 7.0.97
Extension Pack Version: 7.08

I have a Windows 11 host and a Windows 11 guest. I am able to use bluetooth in the guest as long as the bluetooth is first established in the host before I launch the guest from a full boot (not a saved state). For example, if I attach my bluetooth earbuds from the host and then launch the guest from a full boot, I am able to use the earbuds to hear the sound, say, of a video playing on the guest virtual machine. That is, I can use the earbuds either from the host or the guest. My question is this. Say I am running in the manner I just described with my earbuds connected to bluetooth and able to use them both in the host and the guest. If I later disconnect the earbuds from bluetooth and then reconnect them, they then work only in the host. If I try to play a video in the guest, for instance, I get only silence. The only way I have been able to reestablish the bluetooth in the guest is by rebooting the guest while the bluetooth earbuds are connected in the host, as described initially. Does anyone have any suggestions on how I can reestablish the earbuds in the guest after they've been disconnected and reconnected to bluetooth without having to reboot the guest?

[mpack]

The earbuds should not be "shared".

AFAIK, PCs do not have bluetooth. What they have is a USB-Bluetooth adapter, which may be built in. USB devices are peer to peer devices, they cannot be multidropped, so it isn't possible to have an USB earbuds talking to two other endpoints.

Let the host own the earbuds and make sure the guest doesn't try to grab them, i.e. no USB filters that match the earbuds. Any audio produced by the host should play in the earbuds, including audio mixed in from the guest.

[RobertJ234]

Thanks for your reply and the good information that you have provided, which I will certainly use. It's always great to know how things are supposed to work.

Nevertheless, I AM able to "share" the earbuds between host and guest with only one connection, as I've described. I can switch to the host and listen to audio coming from the host. At the same time I can listen to audio coming from guest. So the bluetooth to my earbuds are effectively being shared. If I play the host audio and the guest audio at the same time, I hear both mixed together (just as I would if playing both at the same time with nothing connected to bluetooth and only my PC's built-in speaker).

My question was how to reconnect the running guest (without rebooting the guest) to the shared bluetooth after the bluetooth connection is disconnected and then reconnected.

[scottgus1]

I AM able to "share" the earbuds between host and guest with only one connection, as I've described. I can switch to the host and listen to audio coming from the host. At the same time I can listen to audio coming from guest. So the bluetooth to my earbuds are effectively being shared.

Actually, they aren't, in the default setup. Sound inputs from several different sources can be mixed. That's what those massive desks with the gazillion knobs in a recording studio do. Computers can do this too. The trick is to have only the physical PC do the mixing. Let Virtualbox provide one of the audio sources, let the host mix the various sources together. The Bluetooth headphones should only connect to the host.

how to reconnect the running guest (without rebooting the guest) to the shared bluetooth after the bluetooth connection is disconnected and then reconnected.

Don't try. Let the host connect to the Bluetooth headphones only. Don't do any specific setup to get the headphones in the VM. The host OS will send both host app audio and Virtualbox VM audio to the bluetooth headphones.

[RobertJ234]

You wrote:

Don't try. Let the host connect to the Bluetooth headphones only. Don't do any specific setup to get the headphones in the VM. The host OS will send both host app audio and Virtualbox VM audio to the bluetooth headphones.

Thanks. That is precisely what I do: I connect the earbuds via bluetooth to the host, but use them in the guest. So based on what you have written, when I play, say, a YouTube video in my Chrome browser within the guest, the audio into my earbuds is being controlled by the host. That makes sense.

So back to my question though. If I place my earbuds back into their case, effectively turning them off the bluetooth connection to them is lost. Why when I reconnect the earbuds (from the host) am I no longer able to hear audio out of them when playing audio on the guest? As I've already written, the only way I can do this is to entirely reboot the guest. Then I am again able to listen to guest audio via bluetooth.

[scottgus1]

OK, so it sounds like you're not really fully "sharing" the Bluetooth earbuds. The setup you have, keeping the earbuds in the host and just letting the host mix the VM audio into the host's mix and pumping it out through the earbuds.

However, why the VM loses audio because you shut off the earbuds and why you have to reboot the VM to get audio back is a really good question that I don't know the answer to. We'll need an audio Virtualbox guru to look at this question.

Please provide a log where this problem occurs, and someone might be able to investigate it.

Start the VM from full normal shutdown, not save-state. Run until you see the problem happen, then shut down the VM from within the VM's OS if possible. If not possible, close the Virtualbox window for the VM with the Power Off option set.

Right-click the VM in the main Virtualbox window's VM list, choose Show in Explorer/Finder/File Manager. In the "Logs" subfolder, zip the VM's "vbox.log", and post the zip file, using the forum's Attachments tab. (Configure your host OS to show all extensions so you can find the "vbox.log", not "vbox.log.1", etc.)

[marmel]

Perhaps this actively investigated (assigned) bug report may be of interest:
https://www.virtualbox.org/ticket/20431

tl;dr...there's a new testbuild that addresses the issue-filer's very similar problem