Set video mode on firewire camera

[svif]

Hi

I would like to make sure the video mode is always set correctly when i start my program. Unfortunately there is no vi in the IMAQ for firewire that set the video mode. Can anyone help me with such a vi.

I need to set the mode to: Format 7, mode 0

Thanks,

Simon

[GuenterMueller]

Hello Simon.

Mode and Format can be set by a property node on the IMAQ 1394 Session, located in the Acquisition Attributes.

Best regards, Guenter

[Steffen Hoog]

examples are at \\labview x.x\examples\imaq\1394x.llb
There are an example to set format and mode, too.

[svif]

Thanks for your reply.

As it often is, I found a new question after looking at that example vi.

There is a setting called: "format 7 bytes per packet"

I see that when I change the ROI this value also changes, but I can also change the setting myself. Can "format 7 bytes per packet" be optimized at a certain ROI to maximize the acquisition rate?

[GuenterMueller]

Hello Simon.

Easy answer to this: To maximise the acquisition rate you should select your packet size to the maximum value. But the 1394 bus limits each packet to a maximum size of 4096 bytes - so only quite small ROIs will fit in one packet. 

"Your" camera specification will give you further details of the capabilities of your camera.

Detailled information you can also take from the following NI documentation:

Title: Acquiring from Firewire Cameras using National Instruments NI-IMAQ for IEEE 1394
and
Title: Multiple IEEE 1394 Cameras Produce "Insufficient Resources Available for Required Video Mode" Error (Document ID: 3HRAELV3)

Hope this helps, Guenter