Hi Paulo, > > [...] > > I tested various webcams. One of them didn't include the PTS and SCR > > fields in any packet. All others did. > > Since we're on the subject of frame clocks, I tested a Quickcam Ultra > Vision and used gettimeofday to stamp each frame as it arrived. > > It seems that the frames are always sent with a 40ms granularity no > matter what the frame rate is, except at 30Hz where each frame is 33ms > apart. > > For instance, if I request 10Hz, instead of having each frame 100ms > apart, I get 80ms -> 120ms -> 80ms -> 120ms.... > > So, the only "constant period" modes are 25Hz and 30Hz. > > I thought this might be related to powerline filtering, but I tested > with every setting (starting with no filter at all) and still saw the > same behavior. > > Is this a limitation of the camera?
I can't answer, as I have no knowledge of the webcam internals. Martin Rubli might be able to give more information. Laurent Pinchart _______________________________________________ Linux-uvc-devel mailing list Linux-uvc-devel@lists.berlios.de https://lists.berlios.de/mailman/listinfo/linux-uvc-devel
