[pulseaudio-discuss] bluetooth headset connection and disconnection status

[Tanu Kaskinen]

On Tue, 2018-04-03 at 19:18 +0900, Shinnosuke Suzuki wrote:
> Hi,
> 
> I am developing simple telephony app using pulseauio 11.1.
> I would like to get status for bluetooth headset connection and
> disconnection.
> Is there any way to get status for connection and disconnection for
> bluetooth headset?
> I write a telephony app in C with parec and pacat command to handle
> bluetooth headset.
> So I would like to judge whether app can connect call with bluetooth
> headset.

You can use libpulse to query the bluetooth card status (and you could
use libpulse to also record and play audio - using parec and pacat
sounds quite hacky if you're writing a serious application).
pa_context_get_card_info_list() can be used to get the information
about all cards. If you see the headset in the list, then it's
connected.

The documentation for libpulse is here:
https://freedesktop.org/software/pulseaudio/doxygen/index.html

The card might not have the right profile active, but pulseaudio should
automatically switch to the HSP profile if you create a recording
stream with the media.role property set to "phone". In case of parec
that can be done by passing command line argument
--property=media.role=phone . You can also manually switch the profile
with pa_context_set_card_profile_by_name().

You can get notifications when things change (e.g. a new card appears)
with the subscription API of libpulse.

-- 
Tanu

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