Device Caps not returning valid sample rate values

[IUnknown]

In using DirectShow.net to access capabilities for an input device
(SigmaTel), I get values for sample rate: Min = 11025, Max = 44100,
Increment = 11025. There are multiple device caps pages, but all are
identical.

The device definitely supports a wider range of sample rates, like
16K, etc. So, what is the best way to determine those?

I've also tried to determine these by trial and error... Setting the
device to a standard rate, then reading the rate to verify.
Unfortunately, it looks like the device is accepting some very odd
values. For example, I tried 16001, 16002, and 16003. It accepted all
values, and reading the device confirmed the settings.

This must be documented somewhere, but I haven't turned up many clues
so far.

[Chris P.]

Post by IUnknown
In using DirectShow.net to access capabilities for an input device
(SigmaTel), I get values for sample rate: Min = 11025, Max = 44100,
Increment = 11025. There are multiple device caps pages, but all are
identical.
The device definitely supports a wider range of sample rates, like
16K, etc. So, what is the best way to determine those?
I've also tried to determine these by trial and error... Setting the
device to a standard rate, then reading the rate to verify.
Unfortunately, it looks like the device is accepting some very odd
values. For example, I tried 16001, 16002, and 16003. It accepted all
values, and reading the device confirmed the settings.
This must be documented somewhere, but I haven't turned up many clues
so far.

Generally speaking as all WDM audio devices connect via the Windows kernel
mixer all sample rates that the mixer supports are supported, this is at
minimum from 8000 to 96000Hz. These are not native device rates, but a
converted rate. Devices such as the Sigmatel often only actually support 1
or 2 native rates such as 44.1kHz or 48kHz.

I'm not sure why you are getting the strange device caps, the caps of the
kernel mixer are what typically get reported under XP. Is this on Vista?