Speeded up video

[Raffaele96]

Hello everyone,

I'm new in labview and I'm trying to acquire a video with an USB camera. I'm using the blanck model that I attach to the message but I have a problem, when I open the video created and saved it is speeded up. Do you know why?

Thanks everyone for the help.

[Bob_Schor]

I don't (yet) have LabVIEW 2020 installed on this machine, but I can tell you when I play back videos that I've captured with IMAQdx and see "speed" differences, it has always been because the Acquisition Rate (in Frames per Second, FPS) did not match the Playback FPS rate.

Sometimes this is because I asked to save at, say, 60 FPS, but my hardware (or Image Size or some other pararameter) could only save at 30 FPS.  Sometimes I forgot to set the Playback speed.

Look at your LabVIEW code and see if/where/how you specified Acquisition FPS.  Did you compute "actual FPS"?  How about playback?

Bob Schor

[Raffaele96]

Thank you for the aswer Bob, I'm using 30 Fps but I don't set the playback FPS and onestly I don't know how change this parameter or where I can control it. Where can I find it?

[Bob_Schor]

Open LabVIEW.  Go to Help, Find Examples ...  Look for Vision, Files, Read AVI File.  It shows you how to find the FPS setting saved in the file, and how to use that to "clock" the reading and displaying of the Images saved in the file.

As with all Examples files, open the file, then go to File, Save As ... and choose "Substitute Copy for Original".  This lets you save a copy of this Example in your "user space" and keeps the Example available in its original form for future reference.  Use this technique whenever you intend to work with Example files to avoid accidentally messing them up.

Bob Schor