Posted by David McCall on 01/12/06 20:50

"Jeff_BTFP" <jeffstroming@gmail.com> wrote in message
news:1137096193.206302.62720@g43g2000cwa.googlegroups.com...
> Thanks for your reply.
>
> I would rather buy some Frame Synchronizers or TBC's and stick with a
> more industrial switcher than buy a different switcher. The main reason
> I needed to make the jump to another switcher was because I needed more
> inputs. I could get away with using 5 inputs on the Sony SEG (out of 8
> total). I would be using 3 cameras (all XL-1 Canon's, with no Genlock)
> and 2 DVD decks (with no Genlock either). So none of my sources are
> synched.
>
> How many Frame Synchronizers (or TBC's) would I need to make this work,
> using those 5 sources? I have seen "Dual Channel" Frame synchronizers,
> what I am assuming is that it will sync 2 sources, WITHOUT a Genlock
> Input, however some have a genlock input. Does this mean I could get
> away with 3 Synchronizers (2 sources each) and have 1 extra If i send a
> black burst through the system?
>
> Again, thank you. This is really furthering my understanding of what I
> need to make this happen.
>
For frame-synchs to be of use to you, they will need to be synched to
the black-burst coming out of the switcher. The frame-synchs get
"timed" to the switcher, then whatever you put into them will then be
synched to the system. You need one per non-synched source. If you
find a box with 2 built in, then that would count as 2.

Keep in mind that your actual external source is still free-wheeling,
so, if your source is running slow, the frame synch will double up
frames to keep up with the system. If your external source is fast,
then frames will be skipped.

In addition, it takes some amount of time for a signal to pass through
any device. As a result, your video will always lag the audio by at least
a frame. One frame is not to bad, but a DVE built into a switcher will
lag by at least one more frame. It's pretty easy to get 3-4 frames out
of synch, just by using multiple devices in your video stream. That is the
best argument against using frame-synchs and switchers with them
built-in, but it is your only option if you need to use consumer equipment.
A possible solution is to use an audio delay to move the sound so it can
match the video, or to do it in post.

David



T

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