[pulseaudio-discuss] Multiple Bluetooth sources

[Arun Raghavan]

On Tue, 26 Jul 2016, at 03:42 PM, Philippe Latulippe wrote:
> Hello!
> 
> I would like to connect many Bluetooth sources (devices that emit
> audio over bluetooth) and listen to them simultaneously. I am using
> Pulseaudio 5.0 and BlueZ 5.23.
> 
> I managed to connect a single device and listen to it using the
> loopback module. But when I try to connect a second device, it
> immediately disconnects.
> 
> Using hcidump, I can see that it all goes wrong with this packet, sent
> by the device receiving audio:
> 
> < ACL data: handle 62 flags 0x00 dlen 10
>     L2CAP(d): cid 0x0042 len 6 [psm 25]
>       AVDTP(s): Discover rsp: transaction 0 nsp 0x00
>         ACP SEID 1 - Audio Source
>         ACP SEID 2 - Audio Sink (InUse)
> 
> Notice how the sink is marked as InUse. After seeing this, the source
> ends the Bluetooth connection.
> 
> It would seem that a BlueZ sink can only be used by one device. Is
> Pulseaudio supposed to register multiple endpoints with BlueZ, one for
> each device? Or is this an issue with BlueZ?

My understanding is that this is broadly a limitation of how most (but
not all) Bluetooth devices work. You can't send  multiple A2DP streams
at the same time.

Depending on how many streams you're sending, you might even end up
hitting bandwidth restrictions quite quickly -- just something to keep
in mind.

-- Arun