[wdmaudiodev] Re: USB audio device question

  • From: Tim Roberts <timr@xxxxxxxxx>
  • To: wdmaudiodev@xxxxxxxxxxxxx
  • Date: Wed, 17 Jun 2009 17:26:09 -0700

Pallavi Joshi wrote:
> I have a USB audio device and I enumerate the device, get the file
> name and create a handle to it using the CreateFile function. I then
> use kernel streaming (from the DirectKS sample by MS) to communicate
> with this USB device. I basically first instantiate a capture and a
> render pin on the filter using the KsCreatePin function from
> ksuser.dll. I then use DeviceIoControl function with
> write data from my USB audio device. But the audio playback I hear is
> not good....in the sense its quality is not good. If I play a sine
> wave it sounds broken as if parts of its data are missing. I used a
> USB analyzer to see the USB frames which are being sent and received
> every 1 ms. Here the input frames from the USB are good but the output
> frames going to the USB have "zero packets" periodically. This might
> explain why my audio quality is not good and broken.
> Can anybody tell me why is this happening? Any pointers will be of
> immense help to me.

How are you sending the sine wave data?  How large are the buffers, how
often do you send them, how are you doing the pacing?

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


WDMAUDIODEV addresses:
Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx
Subscribe:    mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe
Unsubscribe:  mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe
Moderator:    mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx


Other related posts: