[wdmaudiodev] AVStream for audio - change of direction?
- From: BlazeAudio Developer <developer@xxxxxxxxxxxxxx>
- To: wdmaudiodev@xxxxxxxxxxxxx
- Date: Wed, 07 Jun 2006 11:15:34 +0530
It started with a question about creating Dynamic Audio Subdevices using
the AVStream model.
The DDK topic with the same title talks about how this can be done with
port class minidrivers. However, there's no mention of how to do that if
using AVStream minidriver model.
I'm assuming that it would be possible to use KsCreateFilterFactor and
KsDeleteFilterFactor to archive something similar.
However there's no clear documentation which tells if this will or will
not work for Audio devices.
This brings up a related, more important question:
If we're writing a new audio driver, should we be using AVStream
minidriver model or port-class miniport?
I remember some discussions on this list a long time ago indicating
AVStream was the model of the "future". The XP SP1 DDK
(2600.1106) also says in the topic "AVStream
Existing minidrivers under
stream class and port class continue to work in Microsoft® Windows® XP.
However, with this release, Microsoft supports the older stream class
driver only on an as-is basis. Vendors may still write audio drivers
using port class.
This would indicate moving to AVStream for future drivers, although port
class is still okay.
However, there are no AVStream audio driver samples (at least, not that I
could locate) in the DDK!
Further, in the newer DDK (3790.1830), AVStream does not have it's own
"group", in fact, it's not referred to in the Streaming Audio
Devices group at all, it's placed in the Video Capture Devices
Also, in this new DDK, in the topic titled "Vendor Audio Driver
Options" - there's no mention of AVStream! It talks about miniport,
USB Audio Class(USB only), AVC Audio Class (1394 only), as well as KS
filter and stream class minidriver (the last two being not
Can someone from Microsoft clarify this apparent change in
And if we're to use AVStream for audio, can we get some samples?
Also, if an existing audio driver is built using AVStream(we have a
client that has one!) - is that headed for trouble?
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