Sunday, 6 January 2013

DATV-Express for Windows

As the majority of people using Express will probably be running Windows I am
looking at how to move my Linux code to the Windows platform. After a lot of
digging around on the Microsoft Website and some help from others I have managed
to capture video from within a Direct Show test application I have written.
I was held up for a while by not being able to control the encoder bitrate. In the end I
found that to change that parameter it was necessary to read it first, these things are
sent to try me (a bit like the sticky N key on my keyboard).

The above photo is the graph created by my program for a HVR-1900 USB2 MPEG2
capture/tuner card from Hauppauge. It sends the captured Program stream out via a
UDP connection. Initially I will use the loopback address to feed the Program Stream
into the rest of the application. Eventually I hope it will all be done using Direct Show
Filters. I have managed to build one of the sample filters that comes with the Windows
SDK. I have not yet managed to create my own. There is a Wizard for building these
things but it does not seem compatible with the version of the MS free compiler I am
using. I am probably going to dig out an old copy of the compiler and use that as I like
a simple life and it will probably be quicker doing that than figuring out how to fix it
for Express 2010.

On the hardware front the team has been discussing sourcing the components for the
board from the far east. In the end I think we decided that while they might seem
cheaper, if we were to get a single counterfeit component on a batch of boards it could
spell disaster. So we are going to pay a bit more and be safe.  


  1. A path to explore also is AVS Video recorder, I use it with Digilite and webcam.

    73's hb9dug, michel

  2. I assume that is a collection of software encoders, if they are done as filters they could be useful. In the end I managed to build my Filter project using a copy of Visual Studio 2003 and then actually compile it with Express 2010. It registers as a filter but when I try to look at it's properties it crashes. I have probably not set up a pointer or something.

  3. Probably best to go with the better components - any idea of UK cost / availability yet?

    1. I did a quick back of the envelope calculation and I estimate the cost will be about £180 - £200 including VAT for a fully assembled and boxed board. Availability depends on whether the new board design works so I can't give you a figure for that.

      I should get one of the new boards in my hands before the end of this month, the layout has been finished.

  4. Thanks Charles that is very useful to know. The chequebook is at the ready