BATC Forum

I'm struggling to get the DATV Express board to work in a Windows 7 32bit only environment.

I've built a graph in GraphStudioNext to suit my hardware and I've got libusb drivers loaded for the board OK.

I've compiled the source for the DATVExpressServerApp from here: https://www.dropbox.com/s/v862dxxswmjgs ... c.rar?dl=0

However, as soon as I run the compiled app it crashes before I can configure it. Here's the event log entry:
===========================================================================================
Faulting application name: DatvExpressServerApp.exe, version: 1.0.0.1, time stamp: 0x562425df
Faulting module name: ntdll.dll, version: 6.1.7601.19018, time stamp: 0x5609fdaf
Exception code: 0xc00000fd
Fault offset: 0x0005f5eb
Faulting process id: 0x868
Faulting application start time: 0x01d10e575e8a33f2
Faulting application path: C:\DATV\Express\DatvExpressServerApp\Release\DatvExpressServerApp.exe
Faulting module path: C:\Windows\SYSTEM32\ntdll.dll
Report Id: 9f240e54-7a4a-11e5-970d-d43d7e024336
========================================================================================
It looks like 0xc00000fd is a stack overflow error.

I've also tried the Cypress USB drivers and got the same result.

Can anyone give me some pointers please?

Clive / G3GJA

Download the executable perhaps ? See if that is OK?

Clive,

There is a possibility that because there is no datvexpress.txt file with the configuration information in
that it might be doing something naughty.

You could run it using the debugger and see where it crashes.

- Charles

Mike: I don't know where you can download the compiled app; I've not managed to find a link for it.

Charles: The datvexpress.txt file content does appear in the app for a few seconds before it crashes so I assume the path is OK. I'll try the debugger.

Thanks chaps

Clive

Clive,

Ken W6HHC will be posting a link to an executable bundle of files on the datv-express website in a few days.
We are just trying to sort out basic driver install instructions and a rudimentary get started guide.

The delay in posting has simply been down to the conference season and people travelling.

- Charles

OK Charles, thanks for that, I'll hold on until that appears.

However, I've made some progress in that having put Visual Studio 2015 on the PC that I use in the shack I can run the server app in Debug mode within VS successfully. It talks to the board as the LEDS light as expected and appears to be taking packets from the Major UDP Sender.

I've tried another compile but I can't get it to work without VS2015.

The end game is to get a Hauppauge USB PVR that has a H264 capability working with the board. According to the properties shown in GraphStudioNext the encoder can run as low as 200ks/S with CBR. I haven't confirmed that what I'm getting into the DATV-Express board is of any use as the PC runs out of steam trying to run VS2015, ServerApp, the Hauppauge H264 coder, Major UDP Sender and MiniTutioune simultaneously.

I might just try something a little less adventurous and give MPEG2 a try from the Hauppauge PVR 350 PCI card in the PC. The hardware coding would take some of the load off.

Clive

I built the project with VS2012, if it runs properly in debug mode it usually means
there is a memory overwrite or timing problem somewhere.
The type of problem that is very difficult to find!

- Charles

I have uploaded a zip file called DATV-Express-Utils_v1.2 with the two apps to the DATV-Express Project web site at www.DATV-Express.com . Look for the zip file on the DOWNLOADS page.

The two apps for the DATV-Express board are:
* DatvExpressServerApp is an alpha-release program to transmit DVB-S DATV running only on a windows PC with the hardware board. (no linux)
* DatvExpressSdrApp is an alpha-release program running only on a windows PC to transmit FM or SSB using the hardware board.
PLEASE NOTE - these two applications are experimental and are likely to be full of bugs. They are provided as a service to the DATV-Express community.

There are three README files included in the bundle...and a brief User Installation Guide is planned as time permits. There is a little more information about both of these two apps that can be found in my ARRL/TAPR DCC2015 presentation that is downloadable at www.W6ZE.org/DATV OCARC website (click on the PRESENTATIONS link). Finally, there are more details about the DatvExpressServerApp for DVB-S that can be found in my DATVtalk13 article in the free eMagazine CQ-DATV issue 27, go to http://cq-datv.mobi . The DATVtalk13 article is titled “Webcams and UDP and DatvExpressServerApp on Windows”. But, you are essentially on your own...so please do not expect much in the way of support
73...de Ken W6HHC

For lazy folk

http://www.datv-express.com/uploads/Sof ... s_v1.2.zip

- Charles

I've downloaded the published app rather than try to compile my own and it works fine.

The main reason for wanting to use Windows is that I bought the original Hauppauge HD PVR from Maplin when they were flogging them off in the hope that some day I'd be able to use its hardware H264 coder. As far as I know there are still no Linux drivers for this box which has the model code 49001 on it.

I installed the Windows drivers from the supplied disk and built a graph to link the HDPVR Crossbar filter through a decoder on to H264 encoder and then into the Main Concept UDP filter. The video bit rate in the H264 coder can be varied from 200kbps to over 10Mbps. The 200kbps rate looked attractive for RBDATV and is much lower than the advertised 1Mb/s minimum rate of the HDPVR.

I started with 2Mb/s and set the DATV Express Server App to 2.5MS/s. Looked for the output on the Minitioune and after clicking the auto PID button got a good picture. However, I cant find any setting where I can change the PIDs and it seems to be preset to 4116 for video. There's no audio because Minitioune doesn't support AC3 encoded audio and I presume that's why the audio PID remains set to 256. That leads me on to another problem. After a lot of fiddling I found I couldn't turn the audio stream off so that the stereo 48kHz sampled audio component is much larger than the video bit stream when it's set to 200kb/s. Disabling the audio data doesn't seem possible as even if I disconnect the graph's audio connections it still comes through. There are a number of other parameters that can be changed in the filters but I haven't found any documentation that might identify a means of disabling the audio stream.

The result is that the muxed stream can't be less than about 600kS/s and that tips it over the 400kS/s threshold in the DATV Express where the filters switch mode and can't remove the aliasing products so not good for transmitting. Minitioune will display the picture with the 200kb/s video rate but it's a bit jerky, probably because its trying to cope with a load of unwanted audio data.

Running VLC in network mode on the same machine as the DATV Express Server App gives a better result. It's very good when running at 2MS/s or more where the DATV Express board's filters are effective so I can at least make some use of the Hauppauge box and try Minitioune with H264 over the air on 70cm or above.