dv video time stamp with analog input

[newwb]

Hi,

I have a dv video which I want to time stamp with a analog input.  For the video, which is dv brought into the computer with ieee1394, LabView calls up a C++ program which then stores the video.  Simultaneously, in the program which calls up the C++, an analog signal is also stored (seperately).  I know it sounds tricky as well as messy but this is the best we've been able to work out, given the uncorroperative nature of LabView with dv camera.  Does anyone have suggections for time stamping these two signals so that I know exactly where in the video the analog signal occurs?  The PCI board we use is the NI 6014, which I know is timestamp capable, but I dont know if it can stamp the video feed since it doesnt come in through the NI card.

All thanks in advance for any help!

Daniel

[Ryan_V[DE]]

Daniel,

Does your DV camera have any sort of timing or triggering signals? Without these, it will be virtually impossible to correlate measurements. It is cetainly possible to accurately time an analog input with your DAQ card, but correlating these to the digital video would be extremely difficult. Is this video streaming in real time? Or are you reading it off of an already-recorded tape? If this video is streaming in real time, with an acquisition started in software, I would suggest attempting to start the software DV reading at the same time as your DAQ task. If you do have an external signal that can trigger the video acquisition, then I would suggest using that same signal to start your analog acquisition.

Hope this helps,

[newwb]

Thanks Ryan,

I would be analyzing the data off line post hoc. So, for example, I could do waht you suggest to start both at the same time (the camera and the acquisition VI), or a thought I had was to start the camera, then, start the VI which would upon execution light an LED. This way in analyses I could zero the video feed to the moment it sees the LED which is also the moment of acquisition begining.

I would be happy to find some sort of trigger which could communicate to or from my camera, but I'm afraid it is a simple DV camera from bestbuy and isn't friendly with this thought.

Thanks again,
Daniel

[Ryan_V[DE]]

Daniel,

If you don't mind an LED at the edge of your frame, then that would certainly be an option... great idea! You could route the ai StartTrigger signal to a PFI line (as an output), and use this to drive an LED. The "Export Signal" property node allows you to do this. This method should provide synchronization within +/-33 msec (the period of a video frame). Would that suffice? Please let us know if you have any other questions, or if you have trouble setting up your LED.

Hope this helps,