Pixellation / Macroblocking

[FrankM]

Anyone notice more pixelation again lately?

I was watching Smallville in HD and had a lot of pixelation going on...

Lots on sportsnetwork too (the spinning logo, etc).

/sigh

[SpinalTap]

I was just going to post a question on this as well....

I am seeing a TONNE of pixelation lately. I just bought a new LG 50PX10 plasma display, and I was worried it was the TV. DVD quality is excellent, so I am thinking/hoping that it is the 9200 receiver.

My signal strength seems good to me (94% for 91 and 74% for 82). I was going to try switching my HDI cable to composite to see how that works.

Could I have a defective receiver? What other things can I look at to resolve this issue?

Thanks.

[57]

Be aware that there is a difference between pixellation and macroblocking. See the Digital Home FAQ on "Acronyms & Definitions". Macroblocking occurs on fast moving scenes due to the limits of MPEG.

http://digitalhomecanada.com/forum/f...splay.php?f=30

[skypilot]

Originally Posted by FrankM

Anyone notice more pixelation again lately? /sigh

Yes, I have noticed more pixelation as of late. I have a 9200 and live in southwestern Ontario, near London. Home from work today and noticed more than usual

I must say that I find I see more of it on TMN, both HD and SD, although I watch more HD. Rome and Stargate Atlantis, etc. This bugs me since I'm paying for a premium service here, although I'd rather it didn't happen on any channel.

Thanks to 57's direction about differentiating between macroblocking and pixelation; I definitely have been seeing more pixelation.

[57]

I've been recording Rome and it's been pristine for the past few weeks. I didn't watch last night's yet. (Rogers, SA8300HD)

[had0ken]

i have noticed that pixelation that occured during smallville priemere too. it was during fast scenes or explosions. also noticed it on csi , anyone know why it happens? is it because my signal is low? only about 69-70% on both

[poncho@home]

I was just about to post about this as well. After looking at a sample image of macroblocking, that's what I got a lot more regalular then before. What can I/we do?

Obviously EV is compressing way too much, a buddy on Videotron never gets this, so how do we go about getting this corrected? Can it be my receiver? I noticed that after a powerfailure once that my receiver had a hard time starting up and ever since, the On screen guide is very slow. Also my receiver often does not have guide information available...

Should I call EV?

[57]

Macroblocking is due to compression. There are two sources of compression.

First there is MPEG2, which compresses the original 1+ Gb/sec stream to 19.4 (or so) Mb/sec. This is a compresson factor of more than 50. When there is too much movement on screen, you'll see macroblocking because the compression can't keep up. There is nothing you can do about this - it's a limitation of the current technology

Secondly, there is the compression that the service providers do. Some don't to any further compression (Rogers Ontario for example). Some do further compression - Satellite due to bandwidth limitations and some channels on some Cable Service providers, depending.

You can complain to BEV (for all the good that'll do...), or you can consider another service provider, but check carefully before switching, it could be worse....

[SpinalTap]

Well, I switched my DVI cable for composite and I can no longer see any pixellation - or at least it is 99% better than it was with DVI. Can anybody explain why this might happen?

[tdti1]

Over compression, the more channels they add the worst the PQ will get, for the best HD and SD you can get a big dish:
http://satellitetheater.com/C-Band%20World.htm

Or try to fix the crap bell is feeding you look into something like this:
http://www.algolith.com/index.php?id=mosquito_hdmi
http://www.algolith.com/index.php?id=dragonfly

[Jeffy]

"...switched my DVI cable for composite and I can no longer see any pixellation..."

LOL. This proves my theory about the difference in the definition of picture quality. Composite is destroying the picture quality that you no longer see the details (including MPEG artifacts).

Yeah, my car looks perfect from 100 feet away too. Same thing.

Obviously, modern TVs should have an adjustment for fuzziness. Heck, it could probably be made automatic knowing the size of the MPEG blocks. Detect FFT peak at MPEG block frequency and apply low pass filtering. Trivial.

[Tonino71]

Hi, I have a sony 46wt520 with a bell 3100 reciever. I find that if I use the
coax out, i get no pixelation or fuzziness, but when I use the s-video or
rca outs, I do get pixelation, only being able to view in pro mode.

Has anyone else noticed this?

Is this normal with bell?

any sugestions or recomendations?

[57]

Originally Posted by SpinalTap

Well, I switched my DVI cable for composite and I can no longer see any pixellation - or at least it is 99% better than it was with DVI. Can anybody explain why this might happen?

Do you mean component video or composite.

Composite has about 400 lines maximum vertical and horizontal resolution (you can test it with a setup DVD). HD connections have 5 X the overall resolution (at least twice the amount in vertical and horizontal). Therefore, any imperfections on the screen are more visible.

S-video has 480 lines maximum resolution and again, the lower resolution of composite or RF-coax may "appear" to make the image "smoother", but you're probably just missing details.

[Battscrew]

I am using DVI on my 6100 and it is very rare that i have an issue. Maybe every couple of months?

[SpinalTap]

Sorry 57, I meant component video (with the seperate red, green and blue cables).

So are you saying the max resolution on component is only 400 lines? So an HD signal coming from the receiver is getting paired down, so I am just not seeing the imperfections now? Is DVI always better?

You also referred to HD connections. Which ones are those?

Sorry for all the questions, somewhat of a newbie and still concerned that I may have to return my tv.