Category Archives: windows

Audio and image support – Gotcha!

I’m currently working on a WPF application to extend a Silverlight control to support the capture of audio and webcam still images.   All seems to be going pretty well using a Logitech QuickCam Communicate STX as the capture device, using Avicap32.dll to handle images and NAudio for the audio.

Or so I thought.  When I deployed the application to my second dev environment, I kept getting the error “NoDriver calling waveInOpen”.  I spent a long while researching what the problem was, and kept coming up with the answer “Everyone says there is no audio driver installed, but I know it is there because I built the machine myself.”

That’s when it hit me.  The light bulb moment.  The moment when one tiny detail that was staring me in the face suddenly made itself apparent.  I was using the second machine in an MSTSC session from my main dev box, and had opted to bring audio across to the main box, too.  A quick setting change in the client configuration for MSTSC and all was well again.  I thought I’d better blog it to stop anyone else beating their head against a wall for an hour.

Windows 7 on the MacBook

I’ve just installed Windows 7 on my MacBook’s BootCamp partition, and so far it looks great.  I’m not new to Win7, having had it installed in a Parallels VM since it was released.  The experience on the MacBook’s native hardware, though, is so much better.  For a start, it doesn’t die when you try to run (or create) a WPF application.  For a developer, that’s a pretty important thing. :)

One niggle, though, I can’t get audio.  I know there’s a fix, but after inserting my Leopard DVD, the drive has stopped responding.  Now I have to boot back into OS X in order to eject the disc.

Oh well, I’m going back to playing with this OS, and seeing what it can really do.

Multiple Async calls to a web service

I’m currently working on a project that requires making several concurrent asynchronous calls to a web service.  Now, the service work fine synchrounously, but change the pattern slightly and I was getting the following error.

“There was an error during asynchronous processing. Unique state object is required for multiple asynchronous simultaneous operations to be outstanding.”

The solution, courtesy of a post on the MSDN forums was to pass a new GUID as a state object.

Problem solved.


Windows Home Server RC2

I’ve just installed the RC2 release of Windows Home Server. It looks pretty good, to be honest. I wasn’t expecting much, but the feature set seems to be rich enough for most users’ purposes. I’ll update this post later when I can tell you how it’s getting along.


I’ve just spent a few hours playing with the server software, and it appears to be quite useful.  I popped the client cd into each of my laptops, and within a few minutes, they were backing their data up to the server.  A few hours later, and everything was backed up. 

I also looked at the remote access features (although I have since disabled them – I don’t want to open up a hole in my firewall if I don’t need to).  Setting my router/firewall to UPNP mode, the server was able to auto-configure everything to allow access from the nasty ole web without hitch.  I am sure that there will be many users who will find this feature very useful, but I’m not one of them.  As I said before I don’t want to open up my firewall any more than I have to.

I also took a chance and installed SlimServer on the box.  I doubt it is supported, but it works well enough so I am happy to leave it on there.  It also means I can migrate the music from my existing SlimServer – handy as the old box is about 3MB short of running out of disk space.

That was a very quick spin through the server’s capabilities.  I’ll hopefully get some more time next weekend to play again.  If I find anything I missed, I’ll let you know.