Friday, 25 January 2013

DATV Express work progresses

Over the last week or so I have been moving the DVB-S encoding from the host
P.C into the FPGA. This will mean that fairly low powered embedded boards will
now be able to use DATV-Express. I was always going to do this but events have
brought forward when this needs to be implemented.

There are other things going on behind the scenes but plans are at an early stage
and are subject to change / cancellation. I have probably said more than I should
have already!

The new FPGA code is so large now that it takes a few minutes to compile on the
free version of Quartus II. The free version is locked to one CPU code and some of
the  incremental build functions are disabled. I estimate the new FPGA design will
use about 30% of the resources on the EP2C8T144C8 chip. So there will still be
room for adding new functions.

I have also been updating the old FPGA code for the rev2 PCB. This will allow
rapid evaluation of the new board when it arrives.

The project team has also been investigating how final production of the boards will
be handled, in other words where the money and resources are going to come from.
This process is ongoing. There is a huge difference between making one or two
boards and making batches of 100+ boards at a time.

I have now built my new PC. It has a 3.5 GHz i7 CPU and an NVIDIA GTX860
graphics card. I also bought a copy of Visual Studio 2012. It looks like most of
the support for Direct Show has been removed. Microsoft want people to move
to Media Foundation. So I don't know whether to move directly to MF which
is only supported by Vista and later or stick with DS and use an older version
of the compiler. The Visual studio 2012 still has the DS libraries but the DS Wizard
has gone.

I am glad to see that NVIDIA include an MPEG4 codec with there CUDA
environment. I also learn't that someone in China has started a project to implement
HEVC in real time. There is a non real time reference implementation of  HEVC
floating about and I hope someone gets that running in real time on an NVIDIA card.  

That is all for now. I hope to have more news about DATV-Express when I post next.


  1. Hi Charles,

    How low powered an embedded board are we talking?

    Will this improve video latency?


    Mike KM7MH

  2. Hi Mike,
    One of the ARM processor boards with a video/audio codec on it. Something like the Raspberry PI or the Freescale i.MX6Q Sabre Lite Board. Seems that repeater builders and portable ops don't want to lug around PCs. Well that is the message we are getting from the street. I have tested MPEG4 reception both on a PC and using an HD satellite receiver so there is plenty of kit available for MPEG4 reception.

    1. I was hoping to hear that the Raspberry PI was a candidate.