Hi Michael, On Sun, Jul 28, 2013 at 6:00 PM, Michael Conrad <mike@xxxxxxxxxxx> wrote: > When I plug either of these cameras into the video plug on a plain old TV, > they work great. When I plug either camera into the 950Q on Windows using > the supplied WinTV software, they work great. When I plug the rear-view > camera into the 950Q on Linux, it works great. But when I plug the security > camera into 950Q on Linux, it mostly works and then the picture starts > randomly jumping sideways (like it is having trouble keeping a horizontal > sync on the signal) and then will suddenly flip to a green-grayscale image > with all bright areas as purple-grayscale. Once turned green/purple, it > remains like this until I reset the camera, but the video is full framerate, > low latency, and looks flawless aside from the bizarre colors. Yeah, there have been some issues with frame alignment on that particular chip, which primarily manifest themselves when using highly unstable video sources. This might sound like a cop-out, but you would be better suited with *any* $29 capture device from NewEgg than with the 950q. I've got workarounds in the driver code which cover most of the edge cases, but they aren't foolproof. > For the tests under Linux, I am using the v4l2 API directly in a simple demo > C program I wrote. It is attached. I tried both the "read" API, and the > mmap API. Both produce identical results. Won't make a difference whether using mmap or read in this case. > My other attempts on Linux had been to use v4l2-ctl to select the composite > channel, and then play the device with VLC or Cheese. Neither were > successful (no video at all) but I need to do this from C in the long run, > anyway. Cheese typically doesn't work with anything other than webcams since they typically don't support all the colorspaces (and the 950q in particular uses one that is unusual for raw video). VLC should work though if you get the correct magic incantation of command line arguments (I use it regularly with the 950q). > Anyone seen anything like this before? Yes, I have. :-) It can certainly be made to work via hacking at the driver (but I don't have a video source which readily reproduces the issue). But with Kworld 2800d units being available for $29 on Ebay, that is probably by far the easier approach. Devin -- Devin J. Heitmueller - Kernel Labs http://www.kernellabs.com -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
