[Ericuse165]

When I watch tv and the picture motion is side to side or very fast(Basketball,Hockey) I see little black lines and spots. You can not see anything when the picture is still or not moving very fast. You can see them very will when the background is very bright or white. When could this be? Picture is not calibrated right or at all dead pixes??



Thanks

[LincolnSpector]

Ericuse165, on 14 March 2011 - 07:26 PM, said:

When I watch tv and the picture motion is side to side or very fast(Basketball,Hockey) I see little black lines and spots. You can not see anything when the picture is still or not moving very fast. You can see them very will when the background is very bright or white. When could this be? Picture is not calibrated right or at all dead pixes??



Thanks

Hi, Eric. What kind of TV do you have. Specifically, I'd like to know how old it is and the basic technology (Plasma, LCD, etc.).

Lincoln

[Ericuse165]

LG LD520 LCD

[LincolnSpector]

Ericuse165, on 15 March 2011 - 01:12 PM, said:

LG LD520 LCD

That's a 120hz LCD, which shouldn't have motion problems. Of course, "shouldn't" and "doesn't" aren't always the same thing.

Here's what I suggest: There's a feature on that TV called TruMotion (maybe TruMotion 120Hz). It's supposed to produce smoother motion, but this sort of feature often does more harm than good. (See Would a 120 or 240hz HDTV Produce a Better Picture?) Somewhere in the main menu system you can turn this option on or off, and maybe turn it down, as well. Find that option and fiddle with it.

Lincoln

[Ericuse165]

Do you think TruMotion would work better if I used a component cable vs a hdmi or probably no change? Its for a HD set top box.

[waldojim]

are these images anything like what you are seeing?

If so, what you are looking at is a result of Interlaced content used by cheap HD providers, and all OTA SD content. What is happening is that full image is not being drawn every frame, just 1/2 the screen - odd lines one time, even the next. Usually, the TV compensates for this on its own if the receiving device sends the original signal. Sometimes the tuning device tries to send the TV the signal it wants without correcting the actual image though, and the TV doesn't know to fix it.

And in some cases, the image just never gets fixed... What you are looking for in this case is an option to De-Interlace. If you use Component video cables, then I can pretty well guarantee that the TV get sent a 1080i signal, and not a 1080P. The set may have a better chance of recognizing the frame issue, and correct the image.

For what it is worth - this is an issue no matter what the refresh rate is. If you have it set up for 120 hz, then it will continue to draw the incomplete frames, and not help anything.

[Ericuse165]

Yes some of the pictures are 100% like what I am getting. I think it it the cable and set top box to because I watched a movie in my ps3 with TruMotion on and the picture was very good. So there is nothing I can do to fix the cable?

[waldojim]

If those pictures were it, then the issue is not the cable. The issue is in the signal. Try this - set your set top box (the one with the problem) to use 1080i.

[Ericuse165]

Okay I will try that sorry for miss understanding also do you think I should try a component cable(I am using a HDMI now)?


Thank you very much

[LincolnSpector]

Ericuse165, on 19 March 2011 - 12:27 PM, said:

Okay I will try that sorry for miss understanding also do you think I should try a component cable(I am using a HDMI now)?


Thank you very much

No reason to apologize. Component will not improve anything. (Nor, for that matter, will it hurt with a set-top box--although it will with a Blu-ray player.)

waldojim made a very good (and probably correct) guess that it was interlacing, and included a good explanation of what it is. I'd like to follow that up with an explanation of how your set-top box's settings may be effecting that.

There are two standards for broadcast HDTV: 720p and 1080i. 720p is not interlaced, so it doesn't have that problem. But it's a lower resolution. 1080i has a higher resolution, but is interlaced. 1080p combines the best of both worlds, but doesn't exist in broadcasts.

A lot of sports are broadcast in 720p because with fast action, interlacing does more harm than a lower resolution. But some networks broadcast sports in 1080i.

Both 720p and 1080i signals have to be converted to 1080p to play on a modern HDTV. The 720p signal has to be upconverted and the 1080i one has to be deinterlaced. Both of these can be done by either the set-top box or the HDTV itself. I can't tell you which does a better job, but it's probably not the one you're using. As a general rule, I think that HDTVs usually do a better job here.

You can control who does these by how you set your set-top box's resolution. I don't know what settings are available on your box, but here are some common options and what they will do to the signal.

Native resolution: The box sends the signals to the HDTV without processing it, letting the HDTV do the upconverting and deinterlacing. Assuming that your HDTV does a better job converting the images (likely) and your box has this option (less likely), it's the best solution.

1080p: The box handles everything, de-interlacing the 1080i signal and up-converting the 720p. This is probably your best bet if the box doesn't offer native resolution or does a better converting job than the HDTV.

1080i: This is a pretty serious compromise if you're watching stations that broadcast in 702p, because it will add interlacing to a signal that otherwise doesn't have it. OTOH, it's fine for a 1080i signal.

720p: The reverse of the above.

Lincoln

[waldojim]

Ericuse165, on 19 March 2011 - 12:27 PM, said:

Okay I will try that sorry for miss understanding also do you think I should try a component cable(I am using a HDMI now)?


Thank you very much

The cable should be perfectly fine.

As Lincoln mentioned above, try experimenting with the output format on the box. If you cannot find the menu option, your best bet is to call customer service for that - as the software, and menus change a lot on those boxes.

If you already own a set of Component cables though, it never hurts to make it easy to prove if that is the issue. As I mentioned above - on most systems 1080i is the limit for component cables, and this will easily force the issue, and prove one way or another that this is the issue.

This post has been edited by waldojim: 21 March 2011 - 01:32 AM

[Ericuse165]

Just a update I switched to component cables and set the box to 1080i output and it fixed the issue100%. Thank you both for the information and helping me fix the issue.


Eric