cctv_down_under 0 Posted December 12, 2003 Ok here is the problem. I had a customer that wanted 16 cameras installed and wanted 2x spot monitors that were fed by 2x 8ch looping switchers so that 8 cameras rotate on monitor#1 and 8 cameras on monitor#2 and all cameras end up back at the DVR. The problem is this, I have tried to use LCD screens with video composite inputs into them and when the cameras switch on the switcher and the signal breaks (between changes) I get a black screen pause on the screen and this only happens on the LCD screens. Explained another way. when the switchers change inputs from cam 1,2,3,4,5,6,7,8 there is a black screen and pause displayed on the LCD monitors between each change. I am pretty sure that this is because the scanning of the LCD does not pick up a signal during the change of cameras and therefore it scans all the other inputs like VGA etc to look for a signal, causing the black screen effect. I would like to know if anyone else has come accross such a problem. Share this post Link to post Share on other sites
cctv_down_under 0 Posted February 10, 2004 I can not believe that I have the only post on this site not to be answered Share this post Link to post Share on other sites
Pat 0 Posted March 10, 2004 Couple of questions. How are the cameras sync'd. Are they line-locked or running on internal? Kind of suspect this could be an LCD monitors version of image roll when switching between cameras that are out of sync. What happens if you switch between cameras manually? Share this post Link to post Share on other sites
cctv_down_under 0 Posted March 12, 2004 manually switching still causes probles, you see to switch the signal need s to stop and refresh and each time this happens the LCD scans to see if a VGA or Composite signal can be found because it can not detect a signal. Does anyone know of any flatscreen compostie monitors other than plasma! Share this post Link to post Share on other sites
Pat 0 Posted March 15, 2004 Do you know the specification of your switcher. In particular for this problem there are two features to look out for a switcher Vertical Interval Switching (VIS) Blank Field Insertion (BFI) Vertical interval switching should stop roll on a monitor BFI will stop the monitor rescanning for another input. Bear in mind that the monitor must be detecting video loss and scanning the other channels within a frame for the described problem to occur. If the video signals in to the switcher are synchronised then the switch between cameras should be less than a frame. So BFI would most likely solve your problem but it costs. Have to tried synchronising the cameras? Share this post Link to post Share on other sites
Joebo 0 Posted March 18, 2004 A quick way to sync the cameras would be to loop 1 camera through a couple of inputs (2 or 3) on the switcher. Hopefully, the switcher is looping so termination won't be an issue and this will be a quick process. Connect camera 1, loop out to input 2, loop out to input 3 and terminate the signal. Then connect the flat screen and the problem should definitely not be prevalent. If it is, I would have to say it is the monitor. If the problem goes away, you'll have to sync the cameras, If you don't have a scope to sync the cameras, you can do a pretty good job by connecting two cameras to the in and out of a monitor (e.g. 1 camera to mon A in and the other to mon A out). Cover up one of the lenses so you don't get the double image. If they are out of phase, the picture will tear, adjust one of the cameras until the tearing stops and then remove the camera that had been adjusted and connect a different camera in its place. Be sure to use 1 camera as your reference camera. Good luck!! Share this post Link to post Share on other sites
rikky 0 Posted June 12, 2004 Which type of switcher and monitor where being used? Share this post Link to post Share on other sites
