What causes these white lines to appear in the lop left of some video recordings? I've seen them many times of the years and they always seem to look identical.

An example

2 Answers 2


That's EIA-608 analog closed captioning data. It should be on line 21, which is within the vertical blanking interval of the SD signal. Either the line was shifted down or the VBI was captured as being active video.


Very likely you're seeing either VITC (vertical interval time code) or closed captions encoded on line 21 of the vertical interval. Those are both part of analog video only, though they may remain after being digitized.

If we could see the video in motion it would be easier to tell.

  • The pulses are too wide for it to be VITC, plus there is only one line. Commented Aug 4, 2016 at 2:23

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