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From: Marcel Holtmann <marcel@holtmann.org>
To: Lars Grunewaldt <lgw@dark-reality.de>
Cc: BlueZ Mailing List <bluez-devel@lists.sourceforge.net>
Subject: Re: [Bluez-devel] question: what does this patch from snd-bt-sco do?
Date: Thu, 17 Jun 2004 02:24:24 +0200	[thread overview]
Message-ID: <1087431863.4309.39.camel@pegasus> (raw)
In-Reply-To: <40D0DFFE.7020701@dark-reality.de>

Hi Lars,

> Now I'm lost again. Is there an audio transcoding somewhere in the SCO
> layer, so that I could simply send PCM_S16 and the SCO layer transcodes
> the audio if the headset does not support this? I mean there must be a
> reason why the original snd-bt-sco developer hardcoded the 8bit format
> instead of using 16 bit.

the reason was me, because my first SCO test was with a 3Com PCMCIA card
and 8bit is less data than 16bit ;)

> What about audio quality during transcoding? MULAW sounds much better
> than PCM_S8.

Default air coding is CVSD with 16bit PCM input coding.

> Sorry that I don't fully understand this bluetooth stuff, I'm trying my
> best here. :(
> 
> I hope I dont make anyone angry or something...

Don't worry, but you should dig through the mailing list archives. You
will find some detailed explanations for SCO.

> sorry, misunderstanding. I'll make a new version of snd-bt-sco that
> builds with alsa-1.0.5a. Nothing for bluez.

Feel free to do so.

> I'd like to help you out with this dynamic alternate setting adjustment,
> but I think I don't know enough usb and/or bluetooth mojo to do anything
> usefull.

Maybe someone should rewrite the hci_usb driver from scratch. There are
more issues with it :(

> To make my headset work for now (need my "phone") I used that bad kernel
> patch again, but I'll try to do everything to avoid that in the release.
> I just have to understand what's going on...

I don't see your problem. Simply use 16bit PCM in the ALSA code.

Regards

Marcel




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  reply	other threads:[~2004-06-17  0:24 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-05-18 10:34 [Bluez-devel] question: what does this patch from snd-bt-sco do? Lars Grunewaldt
2004-05-18 10:44 ` Marcel Holtmann
2004-05-18 10:53 ` Jonathan Paisley
2004-05-18 11:06   ` Lars Grunewaldt
2004-05-18 11:35     ` Lars Grunewaldt
2004-05-18 11:59       ` Marcel Holtmann
2004-05-18 11:57     ` Marcel Holtmann
2004-05-18 13:37       ` Lars Grunewaldt
2004-05-18 14:00         ` Marcel Holtmann
2004-06-16 22:49           ` Lars Grunewaldt
2004-06-16 23:06             ` Marcel Holtmann
2004-06-17  0:04               ` Lars Grunewaldt
2004-06-17  0:24                 ` Marcel Holtmann [this message]
2004-06-17 11:24                   ` Jonathan Paisley
2004-06-17 13:35                     ` Lars Grunewaldt
2004-06-17 15:58                       ` Marcel Holtmann
2004-06-17 20:08                         ` Lars Grunewaldt
2004-06-17 20:28                           ` Marcel Holtmann

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