[wdmaudiodev] Re: silly question about pin property and filter property

  • From: Tim Roberts <timr@xxxxxxxxx>
  • To: wdmaudiodev@xxxxxxxxxxxxx
  • Date: Wed, 28 Feb 2007 11:19:59 -0800

Yong Liu wrote:
> Thank you very much for your reply. I found ways to pass data from one
> filter to the pin attached to another filter, defining a globle
> pointer to the pin created. But as I tested the drive in graphedit as
> an audio capture device, there is no sound out. The virtual driver is
> based on MSVAD, and the application sent audio data to driver through
> property set. In MSVAD, audio data buffer is allocated to
> m_pvDmaBuffer through
> CMiniportWaveCyclicStreamMSVAD::AllocateBuffer(), I copied the audio
> data to m_pvDmaBuffer through RtlCopyMemory(). I searched on line, and
> it was said copyto and copyfrom should be used to manipulate audio
> data, but I do not know how to use copyto and copyfrom. Could you
> please give me a hint?

I don't know the details of MSVAD.  Copyfrom and copyto, as I understand
it, are basically just wrappers for RtlCopyMemory.  Since the memory
isn't really DMA, you shouldn't need anything special.  Are you doing
whatever you need to do to tell it how much valid data you are returning?

Tim Roberts, timr@xxxxxxxxx
Providenza & Boekelheide, Inc.


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