[wdmaudiodev] Re: Kernel streaming question

  • From: Tim Roberts <timr@xxxxxxxxx>
  • To: wdmaudiodev@xxxxxxxxxxxxx
  • Date: Wed, 24 Jun 2009 09:16:50 -0700

Pallavi Joshi wrote:
> I think I understand what you mean by data starving and that is what
> is happening in my case. I am not sending multiple buffers. I do not
> have any timer callbacks. I don't know much about them!
> I will try and figure out how to do this timer stuff. So I need a
> timer callback to tell my output device that the data is ready to be
> sent?
> Thanks a lot for pointing it out.

As I said, your audio device is a real-time device.  The data you send
it are shipped to the speakers immediately.  You have to send it 176,400
bytes every second in order to maintain continuous playback without any

Think about it.  Let's say you send 44,100 bytes, then you wait for 1/2
second.  Those 44,100 bytes will finish playing in 1/4 second, then the
board has no more data.  The speakers will go silent for the next 1/4

How are you generating the data now?  Where does the data come from?

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


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