[wdmaudiodev] Re: PC Audio Capture
- From: Tim Roberts <timr@xxxxxxxxx>
- To: wdmaudiodev@xxxxxxxxxxxxx
- Date: Fri, 08 Jan 2010 10:07:12 -0800
Sushma wrote:
>> Pre-Vista, it is possible to insert an audio class upper filter to
>> intercept the kernel streaming ioctls. It is surprisingly difficult in
>> that situation to figure out what format the audio is in every case, so
>> plan some frustrating test time.
>>
>>
>
> If the implement a audio class upper filter, what IRPs i need to look
> out for capturing the data.
>
All kernel streaming transactions take place in internal ioctls,
IRP_MJ_INTERNAL_DEVICE_CONTROL. Data gets transferred with
IOCTL_KS_READ_STREAM and IOCTL_KS_WRITE_STREAM. You'll also need to
monitor the property exchanges through IOCTL_KS_PROPERTY. There are a
lot of properties being exchanged.
If you don't have kernel streaming experience, you have a LOT of reading
to do.
--
Tim Roberts, timr@xxxxxxxxx
Providenza & Boekelheide, Inc.
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