[wdmaudiodev] Re: White Papers now available

  • From: "Jerry J. Trantow" <Jerry.Trantow@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
  • To: <wdmaudiodev@xxxxxxxxxxxxx>
  • Date: Mon, 2 Dec 2002 11:27:40 -0600

I have not retested the 24 bit playback issue with Win2000SP3 or WinMe
with the QFE.  Using the latest QFE's at the time, I observed truncation
with ever OS except WinXP.  
I used a test function which opens up various formats and sends playback
buffers of known values.  I also installed a filter driver on my audio
device which displayed the usb data sent to my device.  I would be happy
to post the code I used if anyone wants to verify the 24 bit playback
with the SPs and QFEs.

-----Original Message-----
From: wdmaudiodev-bounce@xxxxxxxxxxxxx
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Daniel E. Germann
Sent: Thursday, November 28, 2002 8:30 AM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Re: White Papers now available


Hi, Martin.

Thanks for these great resources.  I was so excited I read them before I
had
breakfast. ;-)

In the Audio Device Performance white paper, I saw that a QFE is now
available for Windows Me to fix the KMixer "audio truncation to 16 bits
on
playback" problem.  I knew about Windows 2000 SP3 having the fix, but I
hadn't heard about the Windows Me QFE.  Thanks.

The white paper also says the truncation problem does not apply to
Windows
98 or Windows 98SE.  Is that correct?  I seem to recall Jerry Trantow
doing
some testing with USB audio devices in July of 2001 that indicated the
truncation did occur in Windows 98SE.  If the Windows 98[SE] KMixer
isn't
truncating output data, that would be good to know.  We've been holding
off
on 24-bit USB devices and WDM Audio drivers because of this issue.

Thank you!

Best regards,
-Dan

----- Original Message -----
> Subject: [wdmaudiodev] White Papers now available
> Date: Wed, 27 Nov 2002 17:42:41 -0800
> From: "Martin Puryear" <martinp@xxxxxxxxxxxxx>
>
> I would like to announce the immediate availability of two white
papers.
>
> --------------------------
> Audio Device Performance and Windows XP: Best Practices for Drivers
>
> http://www.microsoft.com/hwdev/tech/audio/highperf-drv.asp
> ...


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