Qt, portaudio and soundcards

Hello

for my application (software based amateur radio), I basically process
samples from the soundcard. For soundcard interfacing I'm using portaudio, the gui is Qt based, processing is done using C++
Software weas developed under linux (slackware). Recently I moved to Fedora
and ported the software - using Qt creator - to windows (vista home edition).

To my surprise, the software itself works perfectly under vista, I do have - and had -
problems with soundcard interfacing, especially when changing the sample rate.
fedora uses pulse and portaudio and pulse do not seem to understand each other.

In windows the main problems is the soundcard interface, on my laptop
directx gives strange results, not clear to what extend that is due to
portaudio.

Maybe there are standard ways to read and write soundcards within the
Qt framework?

best
jan