[pulseaudio-discuss] Extra A2DP codecs support in bluetooth module

Pali Rohár pali.rohar at gmail.com
Mon Jul 23 08:05:18 UTC 2018


On Monday 23 July 2018 10:55:39 Luiz Augusto von Dentz wrote:
> HI Pali,
> On Sun, Jul 22, 2018 at 2:37 PM, Pali Rohár <pali.rohar at gmail.com> wrote:
> > On Sunday 22 July 2018 11:52:11 Georgi Boiko wrote:
> >> I understand the desire to do it properly and to support everything with
> >> account for the fine detail, but that overcomplicates the immediate problem
> >> at hand: falling behind other platforms and being stuck with SBC.
> >
> > In any way, I do not think it overcomplicate implementation. And until
> > bluez does not provide needed API we are really stuck.
> I don't think this is true for all headset though,

Yes, I did not say something like this.

> also perhaps you
> are trying to connect to a device that has already been paired? That
> could be an influence in this randomness, otherwise perhaps the
> headset is just bugged when it comes to codec selection?

By pairing I mean, bluetooth pairing process. You need to send pin code
or verify that pin code matches. Then both devices (laptop and headset)
put other device into "trusted" list and allows connect to themselves.

> Also codec
> selection should only come into picture with user input, we shouldn't
> be changing codecs by policy since that will only increase the
> problems, so should work out the preferences when initiating the
> connection so if the headset plays nice and remember it then nothing
> has to be changed.

Currently my patch which I sent to mailing list uses pulseaudio profiles
for codec selection. So if we want to stay with this, then codec will be
still chosen by bluez or remote device, but via pactl set-card-profile
(or GUI equivalent) it would be possible to change codec.

Also in future we could implement something like "remember last used
codec for this device" and restore it after new reconnect to have stable
and predicable codec selection/negotiation.

I think that both ideas make sense and is something which user expect.

Pali Rohár
pali.rohar at gmail.com

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