From: "Gix, Brian" <brian.gix@intel.com>
To: "pali.rohar@gmail.com" <pali.rohar@gmail.com>
Cc: "iam@valdikss.org.ru" <iam@valdikss.org.ru>,
"linux-bluetooth@vger.kernel.org"
<linux-bluetooth@vger.kernel.org>
Subject: Re: Determinate EDR speed
Date: Fri, 11 Oct 2019 19:05:56 +0000 [thread overview]
Message-ID: <64060b6a2bc9aee7b7eef0347ee3bafe3fddd18b.camel@intel.com> (raw)
In-Reply-To: <fea0a8efd80c4c444f56d4f3902aeae4f4f9de32.camel@intel.com>
On Fri, 2019-10-11 at 19:00 +0000, Gix, Brian wrote:
> Hi Pali,
>
> On Fri, 2019-10-11 at 20:35 +0200, Pali Rohár wrote:
> > Currently bluez API, method Acquire() already inform called application
> > what is socket MTU for input and output. So from this information it is
> > possible to detect if device supports EDR 3 or not.
> >
> > But it is too late to have this information. I need to send SBC
> > parameters to bluez first when doing A2DP negotiation, this is early
> > steps before Acquire() is called.
>
> This seems to be the kind of information which is fixed, for the life of the pairing.
>
> What if you assumed the lower speed the first time you connected, determined the
> speed during the first streaming, and then either immediately renegotiate (caching the identifying
> information
> of the SNK), or just cache the information for future connections.
>
> Or the reverse, and assume fast, but immediately adjust down if you aren't getting what you hoped for.
>
> In any case, this would be a "Device Setup" glitch which you could note as a routine part of pairing in the
> documentation.
Or, Stream "Silence" the first time you connect, in order to determine throughput. It would add 1-2 seconds to
your connection time perhaps, but would be less noticable to the user.
>
> > Therefore I'm asking for some way how to get information if device
> > supports EDR 2 or EDR 3. This is basically requirement for proper
> > implementation of SBC in high quality mode. So if there are not such API
> > yet, could it be exported from kernel to userspace and bluetoothd
> > daemon?
> >
> > See these two articles for more details about SBC and its high quality:
> >
> > https://habr.com/en/post/456182/
> > http://soundexpert.org/articles/-/blogs/audio-quality-of-sbc-xq-bluetooth-audio-codec
> >
> > > > Is there any bluez API for it?
> > > >
next prev parent reply other threads:[~2019-10-11 19:06 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-11 8:27 Determinate EDR speed Pali Rohár
2019-10-11 18:15 ` Gix, Brian
2019-10-11 18:35 ` Pali Rohár
2019-10-11 19:00 ` Gix, Brian
2019-10-11 19:05 ` Gix, Brian [this message]
2019-10-11 20:04 ` Pali Rohár
2019-10-12 7:23 ` Luiz Augusto von Dentz
2019-10-13 7:36 ` Pali Rohár
2019-10-13 8:45 ` Luiz Augusto von Dentz
2019-10-13 9:39 ` Pali Rohár
2019-10-13 9:49 ` Luiz Augusto von Dentz
2019-10-16 19:06 ` Marcel Holtmann
2019-10-16 19:13 ` Pali Rohár
2019-10-19 19:47 ` Marcel Holtmann
2019-10-16 19:05 ` Marcel Holtmann
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