HD video 'glitches'

[dwalby]

Did a quick search and found a few references to this, but didn't quite get to the root of my question.

Bought a Mitsubishi DLP last night and connected it to a DirecTV HD receiver. Watched a few 30 minute HD programs on CBS last night and noticed during every show a few video glitches where the image 'jumps' but just for a fraction of a second so its not really all that annoying. Have had the DirecTV receiver for a couple of weeks and didn't remember seeing this on the SD channels I've been watching before buying the DLP. Have watched a few minutes of SD programming on the DLP and so far haven't seen it there either, but its too early to tell.

Is this just normal with HD signals, or should I have DirecTV come back out and readjust the dish? The installer seemed to tweak it with the signal strength meter pretty carefully on the initial installation (I was standing next to him on the roof at the time). I doubt this could be a problem with the DLP, or could it? I've got the component video output from the DirecTV box connected to the DLP, and the DLP is in 1080i mode. Can't recall if CBS broadcasts in 720p or 1080i, and I'm wondering if a signal that needs to be format converted might do this more often than one that doesn't.

Any advice is appreciated.

[bda4life]

Let me start out by saying that I do not have a DLP. I have an LCD and a CRT (both HDTV's). I think what you are referring to is called "macroblocking". If I understand it correctly, it occurs when the refresh rate of the tv is not as fast as the signal? Hell I could be way off here.

But this is what I can offer, when watching CSI, I have noticed when they snap a picture, the clarity gets a little fuzzy. I think the sudden, quick motion is hard for the picture. I think it is also caused by CBS using 1080i (interlaced) versus 720p (progressive). Long story short, I think what you are seeing is perfectly normal and not an issue with the new tv.

There are many intelligent people on this site that may have something else to offer. Congrats on the new purchase.

[mjones73]

It's not macroblocking, it's Directv's HD. I have the same issue with my Directv service with HD channels where they occasionally glitch to the side. As for your TV, what model is it? No DLP is 1080i native, it doesn't have a 1080i mode. The TV will take whatever you feed it and convert it to it's native resolution for display.

Macroblocking isn't caused by the refresh rate of the TV not being fast enough either, it's caused by the MPEG2 compression not being able to handle fast moving or changing scenes, usually due to overcompressing or poor compressing.

[dwalby]

The TV is a Mitsubishi 62627, which has a 1920x1080 screen format. I've also heard these sets referred to as 1080p, but many of the them couldn't actually display a true 1080p source like BluRay, but rather took a 1080i signal and converted it to the same refresh rate as 1080p. The newest ones are now fully 1080p compatible, but I don't think mine is so that's why I called it 1080i. That is also what the screen indicates when I select the component video input to the TV from the DirecTV receiver, and that's what the DirecTV receiver claims the format to be on its front panel indicator lights.

To further describe the 'glitch' condition, its as if a few frames of video got dropped. The dropout is long enough to be noticable, but short enough to not really be a problem for casual viewing. If you were recording a movie and wanted it to be perfect it might be a problem then.

Now I've noticed another issue that has me wondering about the DLP itself. Twice in two days of viewing the screen went black for no more than a second and then recovered immediately. I can't recall for sure if it went totally black, or just mostly black, it happens so fast. Could the projection lamp go on/off/on in this short a time if there were an intermittent short in the bulb power connection? My friend says his DLP goes black (as opposed to blue or random noise) when the signal connection is broken, so this also sounds like it could be related to the HD feed being interrupted.

So, I'm not terribly concerned about any of this from a viewing standpoint, because it happens so fast its really not objectionable. But I would like to hear any feedback regarding if these symptoms are typical for satellite receivers or more likely an early warning of future DLP warranty repairs.

[damondlt]

It's not macroblocking, it's Directv's HD. I have the same issue with my Directv service with HD channels where they occasionally glitch to the side. As for your TV, what model is it? No DLP is 1080i native, it doesn't have a 1080i mode. The TV will take whatever you feed it and convert it to it's native resolution for display.

Macroblocking isn't caused by the refresh rate of the TV not being fast enough either, it's caused by the MPEG2 compression not being able to handle fast moving or changing scenes, usually due to overcompressing or poor compressing. This has nothing to do with this post,But the RAVENS ARE KICKEN A** :rockon:But my Hd receiver does this to Sometimes. Not much can be done!