[wdmaudiodev] Re: Problem running an AVStream audio capture filter under XP

  • From: Mike Horgan <mhorgan@xxxxxxxxx>
  • To: "wdmaudiodev@xxxxxxxxxxxxx" <wdmaudiodev@xxxxxxxxxxxxx>
  • Date: Fri, 8 Jul 2011 07:20:28 -0700

I do specify that flag in the descriptor

From: wdmaudiodev-bounce@xxxxxxxxxxxxx 
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Tim Roberts
Sent: Thursday, July 07, 2011 7:56 PM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Re: Problem running an AVStream audio capture filter 
under XP

Mike Horgan wrote:

If I install this same driver under XP sp3 and launch Reaper I again see that 
the device is enumerating under WDM Kernel Streaming system.  If I select the 
device and try to record, the cursor just seems to sit at time "0".  Under the 
debugger I see the capture pin get instanced and the system changes the state 
of the pin from KSSTATE_STOP to KSSTATE_ACQUIRE, but it goes no further.  I've 
verified that the state change to acquire returns success so I'm a bit baffled 
as to what is wrong.  If I run GraphEdit and instance the capture filter, I can 
smart render the pin (it connects up to default DS renderer) and run the graph 
and actually hear the tone from my generator.

I'm at a loss to explain what it is that the XP audio system doesn't like about 
the filter.  Neither the filter, nor the pin are exposing an automation table.  
I'm just letting the AVStream framework handle any properties.  I don't see the 
system querying for any audio specific properties (latency, position) which 
would lead me to believe that maybe I need to include one or more.

Do you have KSPIN_FLAG_PROCESS_IN_RUN_STATE_ONLY set in the pin descriptor?  
Ordinarily, the graph wants to get the first chunk of data while it's in 
"acquire" state, so that it is ready to go immediately on the transition to 
"run".  When that happens, the graph does not transition to "run" until it has 
at least one sample.  This is very useful for video devices (so you get a 
poster frame), but not so much for audio.

The IN_RUN_STATE_ONLY flag should suppress that behavior.  It is equivalent to 
the VFW_S_CANT_CUE return in a DirectShow source filter.


Tim Roberts, timr@xxxxxxxxx<mailto:timr@xxxxxxxxx>

Providenza & Boekelheide, Inc.

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