-
Genlock Question….Does FCP generate it and does it sync audio & video?
We have had this issue for the last 2 years where our video and audio is 2 frames off on output back to beta. It is synced upon entering FCP from the beta deck but upon mastering to beta the video is 2 frames in front of the audio. I have simply offset the audio to correct the problem before outputting.
I have been discovering that some black burst generators produce a genlock signal and other don’t. Our current VAC black burst that doesn’t appear to have genlock needs replacing so we are in process of ordering the Horita BSG-50 but for another $130(of course…more expensive) we can get a Horita that produces a genlock signal. Does anyone know if genlock is the reason that the audio and video are 2 frames off when mastering to tape? Would this lock up the audio and video? Does Final Cut not produce a reference signal on output to keep the video and audio synced? We use a Black Magic Video Card.
Thanks for any help in understanding this problem.
G5 Mac OS X
Dual 2.0 GHz
FCP 4.5 HD
XServe Raid 1 TerabyteG5 Mac OS X
Dual 2.3 GHz
FCP 5.02 Studio
G-Tech G Raid 500 GBs
2 – Lacie Drives 200 GBs -
3 Replies
-
I’ve noticed the blackmagic cards can run without genlock though your picture will move vertically while monitoring, but on playback its stable.
You might want to look into the configuration of your tape decks and the settings in final cut and see if your in non-drop or drop mode.
-
[Lee Burrows] “I have been discovering that some black burst generators produce a genlock signal and other don’t. Our current VAC black burst that doesn’t appear to have genlock needs replacing so we are in process of ordering the Horita BSG-50 but for another $130(of course…more expensive) we can get a Horita that produces a genlock signal. “
I’m not sure what the source of your audio drift is but regarding the Horita and genlock it is important to realize a sync generator has a highly accurate clock in it that generates extremly accurate sync signals. If a sync generator has a genlock circuit, it is a bypass function to allow another device in your system to provide sync (this is not a good idea as only the sync gen has the clock but you may want to sync to the other device for some reason). The genlock feature on the sync generator will allow you to do this. For $130.00 I’d think twice about getting that feature unless you have a very large variety of formats and decks around and feel you may use it often, otherwise you can do it yourself by disconnecting house sync and running a cable to the device you wish to sync to.
Genlock equipped devices can utilize a sync signal or any video signal and will copy that signal and use it for timing. No camera, vtp or vtr will create as accurate sync signal as a sync generator.
[Lee Burrows] ” Does anyone know if genlock is the reason that the audio and video are 2 frames off when mastering to tape? Would this lock up the audio and video? Does Final Cut not produce a reference signal on output to keep the video and audio synced? We use a Black Magic Video Card.”
Sync signals exist in the video not the audio, however FCP locks audio to the video and displays any out of sync timming in the timeline.
[Borjis] “BorjisYou might want to look into the configuration of your tape decks and the settings in final cut and see if your in non-drop or drop mode.”
This is a good place to look for your problem (Borjis’s post)
“everything is broken”
-
Genlock is no mystery to us old guys but you new digital people have misperceptions about what it means or what it does. Save your money. Your 2-frame issue will not be addressed by a genlock source.
bogiesan
> genlock: The synchronization of two television signals at the vertical, horizontal, and chroma phase levels such that the signals may be cut, mixed, or cross-faded without noticeable roll, jump, or chroma shift. Note: Modern usage accomplishes this with a frame synchronizer/ time base corrector, but it may also be accomplished by a closed loop method or an open loop method, the latter using a pair of rubidium clocks and a video delay line to maintain chroma lock.< Try these: https://www.mivs.com/technical/appnotes/an005.html
https://en.wikipedia.org/wiki/Genlock
https://www.webopedia.com/TERM/G/genlock.html
https://www.nvidia.com/object/IO_10793.htmlThis is my standard sigfile so do not take it personally: “For crying out loud, read the freakin’ manual.”
Reply to this Discussion! Login or Sign Up