[pulseaudio-discuss] [PATCH v6 10/11] bluetooth: Add more variants of SBC codec

[Pali Rohár]

On Wednesday 06 February 2019 15:51:00 Luiz Augusto von Dentz wrote:
> Hi Pali,
> On Wed, Feb 6, 2019 at 2:58 PM Pali Rohár <pali.rohar at gmail.com> wrote:
> >
> > On Wednesday 06 February 2019 14:04:28 Luiz Augusto von Dentz wrote:
> > > Hi Pali,
> > > On Sun, Feb 3, 2019 at 4:16 PM Pali Rohár <pali.rohar at gmail.com> wrote:
> > > >
> > > > Specify configuration for Low, Middle, High and Ultra High Quality of SBC
> > > > codec. SBC codec in Ultra High Quality has higher quality than aptX.
> > >
> > > Low and Middle quality don't seems to serve any purpose since we do
> > > drop quality automatically when necessary,
> >
> > It may be useful in more cases:
> >
> > 1) To know what type of quality is used. Auto means "user does not know
> > used quality".
> >
> > 2) To force lower bitrate if higher one is causing problems (and
> > decreasing is not working correctly) in bluetooth transport. E.g. you
> > need temporary lower bitrate and later increase it back. Whole auto
> > quality mode can only lower it, so once it go into low mode it never
> > return back.
> >
> > E.g. you connect phone with laptop, listening music and you want to
> > transfer big file...
> >
> > 3) To do quality comparison. In some cases other side can have problems
> > with higher bitrate. So with this profile you can lower it.
> 
> It might be too complicated for the user to decide, also some remote
> stack may stop at first match if they just have SBC in which case it
> may never select the quality the user want. We could however switch
> the order so that the last used endpoint appears first, it just means
> the bluetoothd needs to remember the last used endpoint. Im still not
> convinced that this will be very useful though, so perhaps Id leave
> those qualities to be enabled somehow, so distros that want to have
> this many endpoits/profiles can just opt for auto-quality which can
> scale to ultra.

Look, for most headsets which have bitpool limited to 53, you cannot use
Ultra High Quality mode until channel mode is switched from stereo to
dual channel. So for this case I separated UHQ mode and not added it
into Auto mode...

-- 
Pali Rohár
pali.rohar at gmail.com