Hi Jeff,
thank you for the response. I have understood that with sample rate
conversion in XP I wont find the
exact right sample rate, e.g. 31995 instead of 32000 Hz.
What I still do not understand is why there is a difference in
samplerates between input and output even if both have been setup for
the same rate.
If both directions apply the same rate conversion the rates should also
be identical, not exactly at the right sample rate but at
least equal. Are input and output treated in different ways?
Is there a sample rate that demands no rate conversion, maybe the
maximum rate available?
Is there a way that an application finds this "native" sample rate in
kernel streaming?
In that case there should be no drift for the maximum samplerate...
Best Regards, Hauke
Jeff Pages wrote:
The sampling rate converter in Windows XP and earlier appears to round all conversion ratios to the nearest factor of 160. For example 44.1/48 is 147/160, which is exact, but 32/48 is rounded to 107/160 which is a little bit off. This is really annoying, but it looks like it's been fixed in Vista.
Jeff Pages Innes Corporation Pty Ltd
----- Original Message ----- From: "Audiodev" <audiodev@xxxxxxxxxxxxxxxxxx>
To: <wdmaudiodev@xxxxxxxxxxxxx>
Sent: Friday, May 05, 2006 6:02 PM
Subject: [wdmaudiodev] Asynchronous input and output
Hello Community,
I have a question which one of the driver developers who read this EMail may be able to answer.
We have measured with directX and kernel Streaming that with the same audio device the input and the output
run at different samplerates. The difference is rather small, approx. less than 10 Hz in most cases but it exists.
I would expect this behavior when using two devices but not for one device and especially when using kernel streaming.
From my point of view soundcards should have one chip for AD/DA conversion running at one fixed clock.
What is the reason that an application has to deal with this problem?
Best Regards, Hauke ******************
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