View Full Version : Lost frames

January 15, 2014, 03:33:44
Hi Stefan and friends,

I'm still struggling with lost frames. I use avistartcapture and avistopcapture to record files in a virtual ram disk (this way we don't depend on physical slow disks). We are triggering the camera externally at 500 Hz (at 96x96 format without binning). Doing 400ms recordings we get between 198 and 200 frames (being 200 the correct number).

The activeX control is also out of the window (this helps a lot!), but we are stuck at these numbers. We don't have any antivirus running nor any other software other than Labview and the Processor Idle State Manager

Do you have any idea where could be the problem? Could it be the ethernet card (do you have any recomendation about brands?), or any other hardware limitation?

Thank you!

Stefan Geissler
January 15, 2014, 12:20:33
It may is a good idea, to count incoming frames without AVI capture. This is an easy task in C++ / C# or VB.NET. In LabVIEW this is quite complicated and LabVIEW may is too slow.

You are absolutely sure, your frequency generator fires 200 trigger pulses? If the frequency is between 495 and 500Hz, then you receive between 198 and 200 frames.
You also are absolutely sure, you 400ms seconds timer is 100% accurate?

For tests like this, I use Velleman frequency generator and an external pulse counter hardware. Then I can compare the trigger pulse count with the image count reliably. All other depends on too many influencing factors

Stefan Geissler
January 15, 2014, 12:21:25
The Processor Idle State Manager has no effect on the GigE cameras and network.