Hello,

I use 4 cameras with Ipi recorder, which are all recognized but only 3 are giving me a picture. Althought, the one that doesn't work, works when I switch it alone.

Thank you ; Sorry but I'm French

Hi
I see other cameras also have very low frame rate. This may be the USB bandwidth issue, or the performance problem of selected web camera model.
Have you tried all posible USB ports combinations?
What PC do you use - desktop or laptop?
What camera models do you use?

It's a laptop computer and yes, I've tried all the combinations. I use a low quality webcam

How many USB ports does your laptop have? It is possible that they all are mapped to a single USB controller. In that case, its bandwidth may be too low to handle 4 cams.
Potentially, there may be some USB compatibility issues. Try to plug each of the cameras individually in each USB port to find whether there are some non-working combinations of specific camera with specific port.
The problem with most wecams, particularly low quality ones, is that they rarely can maintain frame rate at stable level, especially at high values. And that makes recordings virtually unusable for mocap. That is why we recommend to use PS Eye camera. It provides very stable frame rate up to 60fps.