VITS lines visible on television from broadcast signal

[mmcleod]

I recently purchased a Vizio LCD TV and have visible VITS lines on the top of the screen while watching broadcast TV. It's predominately on one channel but I don't see it at all times on that channel and it's visible on other channels occasionally. Vizio is telling me the TV is fine and it's the TV station or my antenna. This particular TV doesn't have any user adjustment of the picture position or size while watching broadcast TV. I'm guessing the TV picture is under sized and / or it's not centered correctly but since it's primarily but not always one channel it's hard for me to argue with Vizio. I have no idea how it could be my antenna. I think their antenna comment is a red hering.
Does this sound like the TV or the stations? Is there a spec on where the VITS lines are broadcast such that they should never be seen on the TV screen?

 

[boba]

Now you know why Vizio is one of the high priced TV's. Usually VTTS is in the overscan of the TV picture.

 

[meinename]

It is the broadcasting station that is sending the visible VBI data and not your antenna or TV's fault.

http://en.wikipedia.org/wiki/NTSC#Lines_and_refresh_rate
Says 525 lines, 486 of which are visible.

Normally in analog NTSC on a CRT screen, the VBI data is projected to the non-visible part of the screen.
http://en.wikipedia.org/wiki/Vertical_blanking_interval

Due to a poor crop job in digital transmissions the VBI data can be painfully visible.

Some TV's have an option to stretch the picture and move the VBI data off the visible part of the screen.
On my Olevia it is called cropping, others may call it overscan or something else.

However this ruins the 1:1 pixel mapping and ruins your HD picture quality.

My local Fox station is notorious for this "VBI data visible-on-screen" crud during movies and other SD content pillar-boxed for their 720p picture.

 

[No Static At All]

Did you try the "WIDE" mode instead of "NORMAL" under the picture tab in the menu? The default setting is "NORMAL". I believe the "WIDE" mode will provide the overscan needed to resolve your issue.

 

[jscud]

Does this sound like the TV or the stations? Is there a spec on where the VITS lines are broadcast such that they should never be seen on the TV screen?

It is the TV, but it can be easily fixed. Go into the Vizio Setup Menu and increase the vertical size of the picture.

 

[TheKrell]

No it is not the TV, nor the antenna! Meinename is 100% correct. Many stations screw up their analog conversion by sending the entire 525 lines, VBI and all, to their digital encoders. The VBI data, such as CC, should (and usually is since this is the law) captured and sent out over a separate digital data stream in the ATSC signal. This should not also be encoded as pictures of data in the video data stream. That's just plain stupid. They should only be digitizing 480 lines of video, not all 525.

Those who have never seen this on their HDTV have what I regard as an unacceptably crappy TV, because it's cropping the signal. What an HDTV should be doing is displaying all of the 480, or 720, or 1080, lines on their digital screen. They should not be discarding part of the picture to compensate for imbeciles at broadcast TV stations.

Sorry for my heated words above. It makes about as much sense to put out a picture of CC data over a digital signal as it does putting up pictures of words on the web. Why why why?

 

[Larry1]

What an HDTV should be doing is displaying all of the 480, or 720, or 1080, lines on their digital screen. They should not be discarding part of the picture to compensate for imbeciles at broadcast TV stations.

I often thought that this is what they do, but when I went to a TV store and compared the Panasonic to LG TV's, they were cropped differently. Now the signal was from a satellite box so maybe the ATSC picture would be the same and the cropping was particular to the factory setup of the input.

 

[Tower Guy]

Does this sound like the TV or the stations? Is there a spec on where the VITS lines are broadcast such that they should never be seen on the TV screen?

It's the station's fault.

It's not easy to ensure that vertical position of SD programming and HD programming are synchronous. HD sync generators have outputs of tri-level sync used by HD equipment and burst black for SD equipment. If analog equipment is converted to digital the conversion equipment often adds three lines of delay. That places the closed captioning on line 24 instead of line 21 in equipment that takes vertical sync from a reference, but video comes from the input source.

The solution is to delay the tri-level sync by three lines as compared to burst black. Native SD-SDI equipment can be re-timed three lines delayed or may need delayed black burst for a reference signal.

http://www.ensembledesigns.com/products/avenue/5400

 

[NotTechSavvy]

Thanks to No Static At All, the STRETCH screen took care of the flickering on the top of my Vizio TV pictureIt was the simplest & most effective solution!