[wdmaudiodev] Re: Vista 5.1 speaker mode question

  • From: Mike Preston <mike@xxxxxxxxxxxxxxxxxxx>
  • To: wdmaudiodev@xxxxxxxxxxxxx
  • Date: Mon, 19 Mar 2007 09:59:23 -0700

   I'm not sure we're talking about the same thing here.  If you use the
speaker configuration wizard to put the device into 5.1 mode, it's still a 7.1 logical device, right? I think you're missing the point of my original question. If a Speaker endpoint supports 7.1 as a maximum configuration, is there an API to determine whether that endpoint will use the side or rear speakers when configured for 5.1 mode?


Hakon Strande wrote:
Those are two different devices. The OS can't switch between a 7.1
and 5.1 logical device seamlessly, the driver has to pick one and
expose that. Then when the user wants to use the outputs differently
a 3rd party driver could enable a task change which would cause the
old device to be torn down and a new one to appear. (streams would

The class driver uses pin config data to expose ONE default device
per codec pin (so it uses what the system vendor has set in the HD
Audio codec per Logo requirements using the BIOS verbtable) and only
that device. The class driver does not see or expose to the OS a 5.1
device if a 7.1 device is occupying that codec pin (port). The pin
config defaults will always be the same (unless the BIOS is updated)
and even then we don't use the new values until the class driver is
uninstalled and re-installed so you are stuck with the logical device
(7.1 for instance) that the system vendor chose. This is By Design as
we have no re-tasking UX in Vista and no seamless/dynamic format
change support.


Hakon Strande | Windows Sound Team PM | (p) 425.705.0637

-----Original Message----- From: wdmaudiodev-bounce@xxxxxxxxxxxxx
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Mike Preston Sent: Wednesday, March 14, 2007 4:12 PM To: wdmaudiodev@xxxxxxxxxxxxx
 Subject: [wdmaudiodev] Re: Vista 5.1 speaker mode question

Hakon, Thanks for the valuable information.  I just wanted to make
sure we're talking about the same thing.  I'm talking about a Speaker
 endpoint on an HD audio codec that supports 7.1, but is configured
for 5.1 mode.  Does the pin configuration you're talking about come
from the verb tables in the BIOS?  Is there an API for getting the
codec's pin configuration that is available above the driver level?
The only thing in the Core Audio API that is remotely related is the
IAudioChannelConfig, but that only allows you to get the current configuration. It also seems to be unrelated to the jack information
 for the endpoint.  Any suggestions?

Thanks, Mike Preston

Hakon Strande wrote:
If it is the Windows Vista HD Audio class driver you are running we
use the HD Audio codec's pin configuration default values to determine the channel mask of the multi-channel device through pin config sequence numbers in the logical device association. If a system vendor has set the pin config values of the integrated HD Audio device to indicate that the 5.1 device uses side speakers
then we expose that to the OS when it asks the driver through the
channel config property request but if the system vendor uses the
pin config sequence values in the multi-channel device association
to indicate that the 5.1 system has rear speakers the HD Audio
class driver will expose that to the OS as the channel mask for
that device instead.

See the chapter "Speaker Configurations" in the HD Audio pin configuration programming guidelines document here for the
background on how we interpret pin config values into speaker
configurations in the HD Audio class driver:


If your repro is not with the class driver and/or not with HD Audio
 solutions then I think you'll have to ask the driver developers
who created the drivers you are using why they expose different 5.1
configurations because Windows Vista uses the channel mask information provided by the driver to decide what type of multi-channel device we are dealing with.


Hakon Strande | Windows Sound Team PM | (p) 425.705.0637

-----Original Message----- From: wdmaudiodev-bounce@xxxxxxxxxxxxx [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Mike Preston
 Sent: Tuesday, March 13, 2007 7:44 PM To:
wdmaudiodev@xxxxxxxxxxxxx Subject: [wdmaudiodev] Vista 5.1 speaker
mode question

I have a question regarding side vs. rear speakers in 5.1 mode in
the Speaker Setup wizard on Vista. I've noticed that on different systems that support 7.1 (i.e. both side and rear speakers are present), on some systems, 5.1 mode uses the side speakers, while on other systems, 5.1 mode uses the rear speakers. How does Vista determine which to use? If anyone has any info on this, it would
be greatly appreciated.

Thanks, Mike Preston

|            Mike Preston          | Home/Office: (360)756-1655 |
| E-mail: mike@xxxxxxxxxxxxxxxxxxx |        Cell: (360)303-9331 |
|     The man who follows the crowd will usually get no         |
|     further than the crowd.  The man who walks alone is       |
|     likely to find himself in places no one has ever been.    |
|                     -- Alan Ashley-Pitt                       |

WDMAUDIODEV addresses:
Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx
Subscribe:    mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe
Unsubscribe:  mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe
Moderator:    mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx


Other related posts: