[wdmaudiodev] Re: Problem with capturing for single sample rate device in XP

  • From: "Perry, Chris" <Chris_Perry@xxxxxxxx>
  • To: <wdmaudiodev@xxxxxxxxxxxxx>
  • Date: Thu, 15 Mar 2007 11:51:32 -0400

Just an observation.


If the systems thinks that it is a stereo stream and you are feeding it
with mono, then you are

effectively rendering the input at twice the expected speed since each
2nd mono sample is

being rendered on the other stereo channel.




From: wdmaudiodev-bounce@xxxxxxxxxxxxx
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of KS
Sent: Thursday, March 15, 2007 11:22 AM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Problem with capturing for single sample rate
device in XP




I'm trying to do an AVStream based driver for a single sample rate
device. in XP  I'm currently seeing some issue with capturing when the
recording stream is set to a different sample rate from my device. My
device only support 16kHz 16bits mono for recording. When I use Sound
Recorder to record a 16kHz 16 bits mono stream, all was well. However,
when I tried to record at other sample rates (8kHz 16bits mono, 48kHz 16
bits mono etc), somehow the application is interpreting 10 seconds worth
of data as 5 seconds, which result in all my recording sound like being
play at a fast forward rate. 


It seems that this time issue (10 second recording become 5 seconds data
to sound recorder), will happen as long as the sample rate chosen for
the recording stream is not the same as my device rate (i.e. any rate
other than 16kHz). Does any know what might be wrong? I'm suspecting
some issue with one of the KSProperty calls, but is not sure about what
to look at. 


I've also check that the stream that was created on my AVStream driver
is always 16kHz 16bits mono, which is what I support.


Thanks for any advice.



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