Vamp make OpenVibe crash

[bburle]

Hi all,

We recently installed OpenVibe on a Windows (XP) machine, to be used with Brain Product Vamp amplifiers. Every thing went perfectly well.

However, once the acquisition server is running and that signals is displayed on the screen, after a while (seems pretty random...), OpenVibe crashes severely and we end up with the famous blue screen ("début du vidage de la mémoire physique" etc...!!!! Sometimes, but not always, an error message reports a problem with USBPORT.SYS

Do you have any idea of what is going wrong ?

Thank in advance,
Boris BURLE

[lbonnet]

Hi Boris and welcome on board !

This is the first time I hear about the problem you are experiencing with the Vamp.
I may be wrong but it really doesn't sound like an openvibe nor Vamp problem. More like an OS crash.
I search the web for that "famous" windows blue screen, and it seems like it may come from hardware or driver problem.

Option 1.
the USB driver on your computer is somehow damaged. The USB driver fails, Openvibe lose the connection with the Vamp badly and crashes. Try to re-install the XP USB driver, maybe it can help.

Option 2.
I experienced that kind of Blue screen of death on my personal computer, and identified the cause : I had a faulty RAM card.
It explains the "random" occurrence of the crash : the crash happens only when the OS try to access the faulty part of the memory.
In this case try to replace your RAM card(s).

I hope one of this solution will work... Keep us updated !

Laurent-

[bburle]

Hi all,

Thanks for your response !! Since you suggested a problem related to the computer, I tried on different computers, and it works (almost, see below) ok ! I tested the ram of the problematic computer (memtest on a live ubuntu cd), and no errors was found... So, maybe the USB driver... I'll try to investigate later.

Now, although it worked ok on the other computers, on all of them I noticed that the signal display tended to freeze when the scale was adjusted (automatically). It was really problematic (up to 50 s late...) before installing the proper version of directX, and version 11 dramatically improved the problem (around 2-3 s late), but there is still a problem. Is this a known issue?

Thanks very much for your support !!
All the best,
B

[lbonnet]

the signal display tended to freeze when the scale was adjusted (automatically). It was really problematic (up to 50 s late...) before installing the proper version of directX, and version 11 dramatically improved the problem (around 2-3 s late), but there is still a problem. Is this a known issue?

We do experience some freeze issue with Gtk when rescaling the signal display.
Most of the time it's not so much though.

The Vamp-16 amplifier that we have is sampled at 2000Hz (or 20k Hz in fast mode). I suppose yours too.
The signal display vizualisation box does not handle such frequency. To display the signal, try a Decimation box before the display, to reduce the sampling frequency to something more suitable (~512Hz is ok, which corresponds to a decimation factor of 4).

We know the signal display has some limitations, this box needs some (unscheduled) revision

regarding the difference between DirectX 11 and an inferior version, I don't see the explanation here... (If someone else has a clue - yann ?)

Hope this helps

Laurent-

[yrenard]

Dear Boris,

it's nice seeing you on this forum.

Indeed, the Signal Display box does not process the input in any way. It is up to the scenario author to downsample the signal to a reasonable sampling frequency, e.g. using the Signal Decimation box. Of course, you will have to low pass filter the signal first to have reliable results.

Tell us if you achieve good results with this set-up.
Regards,
Yann