Question for a skilled Audio Visual Technician?

Question

I am using a scart connected TV, STB, VCR and DVD Recorder combination which in general works very well indeed, apart from one anoying problem.

If I am transfering a video tape to DVD, and press the still picture button on the VCR, the picture pulses up and down at about 2 frames/sec. Yet if I play the same tape and view without the DVD recorder being connected, the still picture mode is perfectly displayed with picture locked and stationary.

I have tried both RGB coupling and CVBS coupling with the vcr and get the same problem with both methods. Have also tried with the STB enabled and disabled. The fault definitely seems to some form of conflict with the DVD recorder, yet having said that, it records the movie with superb quality.

Any advice or good inspired guesses will be most appreciated..........Ron.

Answer 1

It all depends where your video on the TV is coming from.
If you have the VCR only, the video is coming directly out of the video output of the VCR.
If you add the recorder in the loop, there are two possible paths being used.
In one you see the signal captured - digitized - compressed and then sent out in a loop back (in other words, they may show you how the video looks after it is being compressed)
or they may just loop-back the input received .
In both cases, the TV probably receives the signal from a different video pipe, which may explain the jitter.

Answer 2

Tricky one, but I think it has something to do with image stabilisation.. the DVD recorder needs a stabilised image so it knows what's going on. As it happens, the DVD recorder has a knack for keeping track of a moving picture, but anything static will upset and confuse it.
I'm not 100% myself about this, but I have had this problem before myself, and discovered I need a stabiliser unit. I will be interested in what more people have to say..