View Full Version : Sdi Genlocking

Sathya Seelan
05-25-2006, 05:31 AM
Hi. This is my situation. I am currently using VT as a output source to a OB van for a live broadcast. This i smy setup. I have two external PC's coming into my VT. One from IVGA and the other from an axternal scan converter with a component input to my VT. Now both computer inputs are being Keyed using the Keyer. The output is to a SDI output. Since Vt doesn't come with a built in SDI device, i used an external SDI connecter. Which means i give a analog output (Composite) to my SDI converter and from there send out the SDI output to the OB van. I am also giving out a KEY/MATTE output using BOB's Preview/Alpha out through the same SDI converter method. So i have to SDI converter devices. One goes to the FILL/PROGRAM and the second one to the KEY. To Genlock this i get a BLACK/REF cable from the OB van and i plug it in to the BOB's Genlock IN. Now the moment this is done, i have to adjust the vertical allignment from VT. All is fine and cool. Until about a minute or two later, My computer sources (The IVGA and from the scan converter) start dropping a pixel. This happens without fail every 1 to 2 minutes.And by the end of it my genlocking is far off from the original setting. Now because this is a live broadcast i can't afford to constantly tweak my genlock. However this problem with the genlock does not arise when i hook up the analog output staright to the OB van through a Frame Sync. The reason i can't use this fro my live broadcast is because the frame sync is being used for the camera's during the event. Now if i and my company can pull this event off beautifully, the VT would be accepted into a whole new market, and that would make all of us who use the VT seem like demigods to those who use their NLE for live events like this :P So Please some one help on this matter as soon as possible. Thank You in advance.

05-25-2006, 06:32 AM
Don't have any bright ideas about your genlock problem but if picture quality is important and $1000 isn't too dear I'd get the Toaster SDI card. I have it and it works great. That might help to solve some of those problems. Going analog to SDI seems like a kludge that will lead to weirdness down the road. Better to go out digital direct in the first place. That's all I've got...............