[wdmaudiodev] Re: Different amount of data in CopyFrom and CopyTo functions with same audio format.

  • From: Tim Roberts <timr@xxxxxxxxx>
  • To: wdmaudiodev@xxxxxxxxxxxxx
  • Date: Tue, 26 May 2009 14:32:22 -0700

Michail Nikolaev wrote:
>
> I develop analog of Virtual Audio Cable. It is put all output
> data(from CopyTo) to cyclic (big)buffer. Then at CopyFrom puts data
> from buffer do output(capture stream).

How big is your buffer?


> All streams(one capture and one render) supports only one format(the
> same. 44100, 16 bit).

Stereo?  For both?


> CopyFrom and CopyTo function tries to synchronize theirs work (if
> there is no data in buffer, or no space) by little delays.
> When i use Winamp to render sound to my virtual device and
> stdrec32.exe to record sound from my device - all works fine. Sound
> without bugs and buffer is synchronized between CopyTo and CopyFrom
> functions.
>
> But when I use Windows Media Player - ~every second CopyFrom function
> can't read data for capture stream(there is no ~184 bytes). CopyFrom
> function tries to wait data(for example - 10 times by 10 ns) - but
> there is no result.

Did you mean milliseconds there (as opposed to "ns" nanoseconds)?  Do
you get ANY data from Media Player?  That is, do you get buffers which
then stop, or do you get no buffers at all?

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

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