[wdmaudiodev] Re: waveInOpen/waveOutOpen in Vista

  • From: Chinmay Mahata <chinmay.mahata@xxxxxxxxx>
  • To: wdmaudiodev@xxxxxxxxxxxxx
  • Date: Sat, 31 Jan 2009 00:27:00 +0530

Dear Eugene,

Thanks a lot for your quick response.

I am trying to modify our driver code according your suggestion to take care
of this behavioral change in Vista.

I just want to know -- is our observation is correct in Vista or I did some
mistake because of that I am getting this ?

[ In Vista, as soon as I call Multimedia API waveInOpen/waveOutOpen from
application the stream/device goes directly into RUN state and it starts
capturing or rendering.
While in XP when I call waveInOpen/waveOutOpen from application the
stream/device does not go directly into RUN state, instead the stream is in
STOP state.
The stream/device goes to RUN state only when application uses waveInStart
or waveOutWrite call. ]

Could anybody please confirm this?

Best regards,

On Thu, Jan 29, 2009 at 11:05 AM, Eugene Muzychenko

> Hello Chinmay,
> > I need XP behavior in Vista.
> You are unable to change Windows audio subsystem behavior. But if you
> need to start a stream immediately upon creation (for example, to
> be ready for data), you can perform all necessary actions in NewStream
> and/or Init. Stream states managed with SetState are for driver clients
> only. A driver should not change stream state without a client
> request.
> Since a pin instance accepts data IRPs only in Acquire/Pause/Run
> states, you can perform all preparations when a stream state changes
> to Acquire/Pause.
> Regards,
> Eugene
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