[pulseaudio-discuss] [PATCH] bluetooth: Add support for automatic switch between hsp and a2dp profiles

[Pali Rohár]

On Friday 26 September 2014 11:00:39 Arun Raghavan wrote:
> On 26 Sep 2014 14:19, "Pali Rohár" <pali.rohar at gmail.com> 
wrote:
> > On Friday 26 September 2014 06:55:38 Arun Raghavan wrote:
> > > On 26 September 2014 03:06, Pali Rohár
> > > <pali.rohar at gmail.com>
> > 
> > wrote:
> > > > On Wednesday 24 September 2014 19:08:55 Pali Rohár wrote:
> > > >> With this patch module-bluetooth-policy automatically
> > > >> switch from a2dp profile to hsp profile if some
> > > >> application want to start recording.
> > > >> 
> > > >> By default a2dp profile is used for listening music,
> > > >> but for VOIP calls is needed profile with microphone
> > > >> support (hsp). So this patch will switch to hsp
> > > >> profile if some application want to use microphone and
> > > >> after it release it profile is switched back to a2dp.
> > > >> So this patch allows to use bluetooth microphone
> > > >> automatically without need of user interaction.
> > > >> 
> > > >> Signed-off-by: Pali Rohár <pali.rohar at gmail.com>
> > > >> ---
> > > > 
> > > > And with this patch a2dp profile could be preferred and
> > > > has higher priority then hsp. Because a2dp has better
> > > > audio quality and when recording is needed my patch for
> > > > module-bluetooth-policy will switch to hsp. What do you
> > > > think about it?
> > > 
> > > I'm not in favour of an exception-list-based approach (too
> > > much of a moving target). I'd written something similar in
> > > the past based on the media role. I'd prefer something
> > > like this since it allows us to take action based on what
> > > the stream is meant to be doing, rather than having a
> > > blanket policy that may or may not make sense.
> > > 
> > > http://cgit.freedesktop.org/~arun/pulseaudio/tree/src/modu
> > > les/ module-profile-switcher.c?h=bluetooth
> > > 
> > > The intention when we last discussed on the list wast to
> > > integrate this into module-bluetooth-policy (the patch
> > > predates merge of m-b-p).
> > > 
> > > -- Arun
> > 
> > This approach depends on that output stream set by
> > application will have correct PA_PROP_MEDIA_ROLE. So
> > basically will not work with any existing application. So
> > this is useless for me and for other people too.
> 
> Why not fix said applications? Exposing this metadata
> correctly allows several things, such a automatic routing,
> echo cancellation/noise suppression, AGC.
> 
> The fix can be made via code or starting the app with an
> environment variable set.
> 
> -- Arun

Backward compatibility. There still will be non trivial set of 
applications without PA_PROP_MEDIA_ROLE. Plus there are more 
closed source applications which you cannot modify. And starting 
application with some special ENV does not change anything. Still 
is needed user interaction and it is easier to switch a2dp 
profile to hsp as opening xterm, setting ENV and then starting 
application. Plus applications with using pulse-alsa wrapper will 
never set that PA_PROP_MEDIA_ROLE.

So I think exception list is only possible solution without 
modifying existing applications.

Or do you want to modify *ALL* existing applications which 
exists?

I want something which works not which works only for new 
applications and application which will be patches in future and 
waiting for new released version...

-- 
Pali Rohár
pali.rohar at gmail.com
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 198 bytes
Desc: This is a digitally signed message part.
URL: <http://lists.freedesktop.org/archives/pulseaudio-discuss/attachments/20140926/96b5524f/attachment.sig>