CompuServe Thread

Forum unknown · Videophile

# genlock

3 messages in this thread
#69356From: gene lambertMay 25, 1987 10:39 PM
Joanne, thank you for what may be the definitive reply to my genlock problems. At least I may be able to lay the thing to rest. Your "fix" is exactly the same thing that I arrived at – loose the generation by outputing to tape, then running that through a TBC. As I may have reported in the message you read, CBM wanted me to send it back in on a "priority return", as they had seen units with the symptoms I described. What they would do about it they didn't say, and I have been suspicious enough to -Yep the unit here until I found out more. It really is a shame…the Amiga can be a useful graphics tool for non-broadcast and industrial video when you choose your ground. You mentioned running the signal through a proc amp in order to straiten things out. I tried that with our Panasonic 5500 switcher, which has a proc amp which re-inserts blanking. I can't recall the exact results, but I do remember that for some reason it liked the genlock's raw signal even less than the TBC's (and they didn't even think it was a color signal). Using tape as an intermediary is the only acceptable way that I have found to deal with the genlock. I should mention here one use I have for the genlock that may interest you at Viacom if you or anyone you know is using a Chyron VP-1. I have written a VP-1 driver for the in MBasic which has helped me a lot in doing C.G. for commercial spots fast enough not rippped apart by the producers. The heart of the program is the use of the mouse pointer on-screen to move text lines accurately wherever you want them without the iterative guesswork that a word processor and skip commands entails. Using the genlocker, you have on the Amiga screen all at the same time your Chyron output, live video, and the program's text editor. In order to move text, you simple point and click the point on the text line you wish to move, then drag it to the point on the video image that you want it to end up. All other formatting and text commands, such as color, font, italics, etc., are handled with pull-down menus. Let me know if you are interested and I will upload this for
#69444From: joanne bandlowMay 26, 1987 8:43 PM
Wow… the VP-1 driver sounds neat. Unfortunately, we have the Amiga here in Cleveland, but our nearest system with a VP-1 is in Long Island, NY. I was puttering around with some ideas for VP-1 drivers for the CoCo and C-64, but never got one finished. I wonder if yours can be converted…… Getting back to Genlock, I suspect the vtr fixes the "lost color" problem because of AGC acting on the colorburst (or what's left of it!) and bringing it up to a level that can be recognized by the hetrodyne circuitry of the vtr. Anyway, it works for the time being. As far as proc amps, there are many different varities. Some simply "stretch" and clip the sync to lop off the noise in the sync tips…. others genlock to the input with an internal sync gen chip, then completely throw out the old sync & insert new. Some even give you phasing controls for horizontal sync and subcarrier (burst) phase, but those are the really expensive ones. I'm working on my own version of the above, using the National Semiconductor sync gen chip, but I'm still in the "puttering around" phase….
#69444From: joanne bandlowMay 26, 1987 8:43 PM
Wow… the VP-1 driver sounds neat. Unfortunately, we have the Amiga here in Cleveland, but our nearest system with a VP-1 is in Long Island, NY. I was puttering around with some ideas for VP-1 drivers for the CoCo and C-64, but never got one finished. I wonder if yours can be converted…… Getting back to Genlock, I suspect the vtr fixes the "lost color" problem because of AGC acting on the colorburst (or what's left of it!) and bringing it up to a level that can be recognized by the hetrodyne circuitry of the vtr. Anyway, it works for the time being. As far as proc amps, there are many different varities. Some simply "stretch" and clip the sync to lop off the noise in the sync tips…. others genlock to the input with an internal sync gen chip, then completely throw out the old sync & insert new. Some even give you phasing controls for horizontal sync and subcarrier (burst) phase, but those are the really expensive ones. I'm working on my own version of the above, using the National Semiconductor sync gen chip, but I'm still in the "puttering around" phase….