Weird pulsating white-dotted line at the top?

[dvdjojo]

I am backing up old PAL VHS tapes onto DVD disks.
The captured avi file has a single, white pulsating line at the top of the
screen (sometimes up to 6 lines below the first visible line)
which seems to contain incrementing encoded information.
Is this a timecode produced by the camera or is this done by the VCR?
How do I get rid of it?

It is not a big deal but can be annoying since it is quite
dynamic and the white line appears like a pulsating collection
of white dots... for the whole duration of the movie!

This is my setup:
SOURCE: PAL VHS tape
Aiwa multysystem VCR (composite out set as NTSC)
SONY NTSC DCR RTV25 (signal through onto firewire, no tape in camera)
Adobe Premiere (capture in NTSC)
TMPGENC (convert to MPEG2)
TMPGENC AUTHOR (burn with LG-4081B)
DESTINATION: DVD-R

[holistic]

Anomalies, noise, or static in digitized video can be caused by any of the following:

* Video head noise from a VHS player
* Faulty or low-quality cables
* Faulty digitizing hardware

Sounds like 'head noise' . If you are to view on TV ignore it. Due to TV overscan you will not see it.
If you are going to view on computer monitor (and it annoys you) then cut it .
ie. cut 8 pixels from top giving 720*472 + (8 black) for 720 * 480

[mats.hogberg]

To me, it sounds like a binary frame counter. It's probably embedded in the video by the camera. Easiest way to get rid of it is to simply crop out the line(s) at the top when encoding, but like holistic says, on a TV the line will be out of the picture due to overscan.

/Mats

[The_Doman]

Don't CROP it, better put a black border over it so the picture size stays the same.
Most of the time i put a small black border around the whole video to hide those videolines with unwanted noise.

[seinman]

Another possibility is that it's the closed captioning data. I'm not sure of the exact specs for PAL, but for NTSC, line 21 is used for captioning data, and 22 is where the video starts. Many capture cards can capture line 21 as video, so you'll see one thin line across the top with blinking black and white dots. Of course, you'll only see that if you're capturing from a captioned source, such as a recording of a TV broadcast.

[Duchess]

If the recording was made from analogue television what you are seeing is probably teletext data. This is transnitted in the unused lines and usually appears at the top when viewed on a comnputer. Of course on a normal television it would be above the viewable area of the screen unless your height adjustment is out of kilter.

[dvdjojo]

Thanks for your reply.
TMPGENC can cut, and I've done that before. But how can I cover it with a black border you are suggesting? Do you use different software? or does TMPGENC offer that function too?

I was rather interested in knowing what is the real reason is and if I can avoid it. It is clearly a line which is meant to be hidden and which is now becoming visible, probably due to PAL-NTSC or framerate conversion?

It is NOT an analogue distortion but clearly digital in nature and contains among other encoded information a continually, fast incrementing binary value such as framecounter or timecode or something of that nature.

Regards, Jiri

Don't CROP it, better put a black border over it so the picture size stays the same.
Most of the time i put a small black border around the whole video to hide those videolines with unwanted noise.