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.