CompuServe Thread

#Video Centering Blues

5 messages in this thread
#2146From: Mike BerroAug 22, 1988 8:16 PM
Nick, Use the program called "Preferences" on your Workbench disk. In the middle of the Preferences screen is a square box with an "L" shaped gadget in it. Position the mouse pointer over it, hold down the left mouse button, and move it around slowly. The display will follow your movements. DO NOT use the Amiga monitor as a guide for the centering. One reason is that the monitor has a horiz and vert centering control, and may be misadjusted. Center the display according to your VCR monitor (which is more likely to be accurate), then adjust your Amiga monitor to be centered. BTW, that's why in video there is a "safe title area" and "safe action area". Safe title is about the size of the non-overscan Amiga display, and safe action is a little larger. TV programs (normally) keep the titles within that area so that even people with mis-adjusted TV's can see them. —Mike
#2176From: Nick MooreAug 23, 1988 12:06 AM
Mike, Guess I overlooked the obvious regarding Preferences! I use The Director and since it boots to a cli the idea of using Preferences didnt occurr to me. BTW, another thing that is driving me crazy is the inability of my genlock to lock on to the signal of an image that has been recorded with the source VCR on pause. My idea was to pause the source image and record that still image on VCR #2, then to use the recording from VCR #2 as a source over which I would overlay graphics from the Amiga (A sort of poor man's Perfect Vision). Trouble is, the computer generated graphics jump all over the screen when genlocked to the still image. The VCR I use for source is a 4-head model (Sylvania VC4040AT01). Do you know of a way around this? Would using a video camera to tape the still image directly from the monitor screen give me a stable enough image that I could use a genlock with it (assuming the quality of such an image would be acceptable)? Any suggestions would be appreciated! Thanx, Nick Moore
#2228From: Mike BerroAug 23, 1988 5:16 PM
The problem is that the video rate in pause is no longer 29.97 because the heads are running at the same rate but the tape is stopped. My VHS home VHS machine (NEC-5000) has a digital freeze, which works great. You will need either a digital freeze (which is what Perfect Vision has built-in, but not DigiView), or pointing a camera at the screen will sort of work. Again, since the pause rate is different from the camera rate, you will get a thin white line rolling (slowly) through the monitor image. If you are just lining up the Amiga graphics with the video, that should work OK. —Mike
#2250From: Nick MooreAug 23, 1988 9:31 PM
Thanks for the information, Mike. The effect I am trying for is to introduce the subjects of a video by freezing a frame with their faces prominent and genlocking their names underneath. I guess to do this properly I am going to have to spring for a frame-grabber of some sort, probably PerfectVision. I can see where a VCR with digital freeze would definately be an asset in this sort of thing. Nick Moore
#2271From: Mike BerroAug 24, 1988 12:07 AM
Nick, Sounds like a frame-grabber is the way to go. There are a few out now, so shop around, and ask opinions about them in this forum. —Mike