Hi Julien,
On Friday 11 May 2007, julien quelen wrote: > Hi all, > > I am trying to build a synchronized multiple cameras capture. > I started with 2 Logitech QuickCam UltraVision USB webcams. > > I have difficulties synchronizing them. > > In my tests, I manage to extract the exact timestamp of each captured > frame. I'm curious, how did you do that ? Which time source did you use ? > So then the synchronization can be made by sofware (comparing > timestamps). But I would prefer the cameras to be directly synchronized > at the source (shot on each camera is taken at the same time). That's an interesting idea. Both cameras have a common time source (the USB SOF tokens), so they could in theory start streaming at the same time. In practice, the feature will have to be implemented in the camera. > The only way I found to do that for the moment is starting the 2 cameras > at the same time (simultaneous call of VIDIOC_STREAMON for the 2 cams. I > use mmap method, USB isochronous transferts). Frames appear to be more > or less synchronized. However sometimes, the 2 cameras start totally > dephased. > > Is there a way to be more precise in the image capture start? I don't think there's currently a way to synchronise acquisition on several cameras. I'll pass the idea to Logitech, they might add the feature to future models. Best regards, Laurent Pinchart _______________________________________________ Linux-uvc-devel mailing list [email protected] https://lists.berlios.de/mailman/listinfo/linux-uvc-devel
