[Gary Reece]

Hi Francisco,

Depending on the GVG100 you are using you have some options.

What most professional installations did with non-synced sources for a Grass Valley switcher was to run the source into a Time Base Corrector (TBC). The TBC is locked to the house sync generator and can be timed into the switcher as you would any source that can lock to the house and be adjusted. The TBC has enough of a buffer to hold the field or frame until it is the right time to release it to the switcher. The one drawback in using a TBC is that you will add a frame of delay from the source to the switcher. You may need to add a frame of delay to the audio to be happy with the result. Used composite TBCs are plentiful and very inexpensive with many facilities having transitioned to digital.

Another way of dealing with this might be to use the un-synced camera as your house sync. Run the signal into the sync connector of the switcher and then extend the signal from the loop through to the selected input. This only works if you have one such camera and everything else can be locked. It also only works if your switcher can lock to a single video signal. Without the regen option you would have to have a generator that produces all three of the required drive signals.

The GVG SCB-200N provides all of the drive signals you would need to provide house sync to any GVG100 switcher configuration. In addition to all that the SCB-100 does, it can be locked to an external source. It could take camera video and provide house sync for the rest of the system.

I don’t like using a consumer camera, or any camera for that matter, for house sync because of the risk of loosing sync with the loss of power or other camera changes. But it might be a way for you to get by with what you’re doing.

[Gary Reece]

You can time a GV100 with color bars and come very close to what you would do with a WF/Vector Scope.
If your do not have the regen option card you will need a sync generator that produces the external drive inputs to the GV100. With the option installed you only need color black to the ref input. Use the appropriate generator that also includes color bars.

Ideally you will run each input through something that will allow you to adjust gain, or the source will have such an adjustment.

You will need to run color black to all of your sources. It is best to take this sync signal into a DA and then fan out to each source from there. Other option is if each item has a loop through and you can chain the sync from one to the next.

Run color bars into one of the inputs and your sources to the others. Create a spit screen with the color bars on the bottom and one other source on top. Set your source (camera, etc.) to generate its internal color bars, or (deck) play content with color bars). Split the screen on the large white block at the bottom. Adjust your gain until the two halves of the white block match.

Reposition the split in the center of the upper bars.

Adjust the horizontal phase of the source until the bars align vertically. If one source has fatter bars and only one place will align pick one to the left, like between grey and yellow.

Adjust the coarse phase of your source until you get bars at the top that are as close as you can get to your standard on the bottom. Then adjust the fine phase until they match.

Adjust the color or EQ adjustment of your source until the bars blend as best possible with no visible split.

Repeat steps as needed to refine the adjustments.

You may never get it perfect. NTSC = Never Twice Same Color, but once you get it as close as you can you are good to go.

If your picture jogs at the end of a transition you need to fine tune the Horizontal phase.

Also, there are course and fine phase adjustments in the GV100. Use them only to calibrate the standard from your generator so that the standard appears correct. Without a waveform monitor you will have to decide with your eye if the colors are correct. With experience you will get close and without bars recorded to your master and a monitor to evaluate them, there will be few who could challenge your colors.