Macroblocking? - Canadian TV, Computing and Home Theatre Forums
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post #1 of 26 (permalink) Old 2010-10-19, 01:28 PM Thread Starter
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Macroblocking?

I'm getting terrible macroblocking (which I was erroneously calling pixelation until recently) on most HD channels. I had a technician over, he checked the setup, said everything was fine, and claimed he didn't notice the problem and that it was the same quality as his setup at home. I went to a local dealer that sells both Shaw Direct and Bell, and watched them side by side for an hour. I rarely noticed macroblocking on the Bell setup, while it was as prevalent on Shaw as at my house.

Several people I've mentioned this to, who have Shaw Direct, say the HD is great. I'm beginning to think I'm taking crazy pills here; is it possible that nobody else notices or cares how bad the compression is on Shaw Direct? I've read lots of anecdotal reports that Bell has poor HD picture quality, but the setup at the dealer, and at a friend's place where I watched it recently, are hands down better than Shaw.

Does everyone just find this acceptable? Most of the poor Bell reviews I've seen are a couple years old; maybe the launch of Nimiq 4 helped the situation? Or have Bell already made the transition to MPEG-4 while Shaw haven't? Or maybe Bell compression or decoding is introducing other compression artifacts that I personally find less objectionable than macroblocking? Does anyone have a similar experience to mine?
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post #2 of 26 (permalink) Old 2010-10-19, 01:57 PM
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If you search this forum for macroblocking, you'll find lots of previous discussion of the topic. BTV changes all their incoming signals to 720P, which tends to make the picture "softer" which masks the macroblocking somewhat. The following BTV PQ thread is up to date with recent comments, despite it starting a while back.

http://www.digitalhome.ca/forum/showthread.php?t=102020


It's very important to properly optimize your equipment, especially the TV settings, which can exacerbate the macroblocking, especially if you're still in one of the default video modes. Here's a post on Optimization:

http://www.digitalhome.ca/forum/showthread.php?t=76161

Changing the TV settings to the appropriate picture mode and reducing the sharpness can help with macroblocking. The sharpness setting on most TVs or the settings that most people use, adds artifacts like ghosting, which can make the picture "appear" sharper, but is inaccurate and hurts picture quality. Edge enhancements can also make things worse.


People may not realize that different TV inputs have different settings, especially if they've just switched providers and are now using a different TV input.


Some people are also more prone to seeing compression artifacts. They are indeed present and macroblocking is a fact of life due to compression of the signals (by the broadcaster and by the service provider). Once you have optimized your system it can be minimized. It's actually amazing that the original signal which contains over 1.5 Gbps can be compressed by roughly a factor of 100 and still look as good as it does. The broadcaster compresses the signal down to a maximum of 19.4 Mbps from over 1 Gbps and the provider often performs additional compression. Pixellation is a totally different matter and has also been discussed in the SD forums.


Here's a post useful for those new to the forums - FAQs, Search Tips, Optimization, etc:

http://www.digitalhome.ca/forum/showthread.php?t=57741

I've moved your post to the SD forum since you posted in the incorrect (Shaw cable) forum.

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post #3 of 26 (permalink) Old 2010-10-19, 02:36 PM
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I've had both Bell TV (a few years ago) and Shaw Direct ever since and from my experience Shaw Direct has much better picture quality. The picture quality is even better with the new 630 receiver then I had on my 530 and 505 receivers which has really impressed me. I have had microblocking with Shaw Direct, and to eliminate it I had to spend a few hours tweeking my dish to get it as best as possible. Optimizing the dish eliminated the problem. There have been others that have mentioned it could be due to excess heat as well, so those are two things to consider. Another thing that is rare but does happen to people is tree branches that move in the way of the signal to the dish when it is windy. If you do not see a high quality picture with Shaw Direct I would follow 57's advise that your TV is not setup as well as it should be.
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post #4 of 26 (permalink) Old 2010-10-19, 03:32 PM
 
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Rangers/Yankees on 240 (RDSHD) was horrible Monday night with macroblocking (on my 530). Switched over to TBS on DishNetwork - BEAUTIFUL!

I noticed alot of macroblocking on RDS HD as a matter of fact. I wonder if there is something going on with Shaw on some of the channels...
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post #5 of 26 (permalink) Old 2010-10-19, 06:55 PM Thread Starter
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Strange, I did search, and tried to post that as a reply in an existing thread on Shaw Direct picture quality (won't post the link as I understand new members can't do so). It ended up creating a new thread. Sorry about that, please feel free to move it there, I don't mean to clutter up the forums.

As for the TV settings, my main set (Philips 55PFL5505) was calibrated professionally, while my second set (LG 42LG30) is using calibration settings I found, I think, on a CNET review (the TV was calibrated in what they described as low-light conditions). Even with the sharpness reduced to levels where I find it too soft, the macroblocking really stands out on both sets.

I guess it may just be a matter of preference, the "softer" look of the Bell or the more noticeable macroblocking on the Shaw Direct; I'm kind of leaning toward the former. Our local cable company has excellent HD quality, though they have fewer channels, so that's another option I guess.

I searched and I can't find any authoritative answers about when and how the transition to MPEG-4 will take place on Shaw Direct. Has anyone heard news on that? I'm still within a time frame where I can return the receivers for a refund. I don't want to back the wrong horse, so to speak. I'm hoping the launch of Anik G1 and/or moving to MPEG-4 compression will allow them improve the HD picture quality, which at the moment I find unacceptable.
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post #6 of 26 (permalink) Old 2010-10-19, 07:25 PM Thread Starter
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Quote:
I had to spend a few hours tweeking my dish to get it as best as possible. Optimizing the dish eliminated the problem. There have been others that have mentioned it could be due to excess heat as well, so those are two things to consider. Another thing that is rare but does happen to people is tree branches that move in the way of the signal to the dish when it is windy.
I had thought that might be the case as well, as there is a tree in the direction the dish is pointing, in my neighbor's yard. But the local guys Shaw Direct contracts to do installations were the ones that chose the mounting location, and when the tech came to look after I first reported my problems, he said the elevation angle is steep enough that it should be well above said tree. My signal quality is rarely less than 80 and usually 90+, and the ECB No. varies from about 6.5dB to 8+dB depending on channel. Would interference from tree branches not manifest itself as lower signal quality / ECB?
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post #7 of 26 (permalink) Old 2010-10-19, 08:08 PM
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Originally Posted by teamtrigor View Post
My signal quality is rarely less than 80 and usually 90+, and the ECB No. varies from about 6.5dB to 8+dB depending on channel. Would interference from tree branches not manifest itself as lower signal quality / ECB?
Yes it would. You should really be shooting for an Ecb of 7.0+ for HD channels and 9.0+ for SD channels. When my Ecb dropped below 6.5 on HD channels is when I experienced macroblocking. I wish you could see the stellar quality of the picture I have, it is far superior to what Bell TV offers. You have the compression idea wrong, it is Bell TV that for the most part puts more channels on thier HD transponders.
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post #8 of 26 (permalink) Old 2010-10-19, 11:06 PM
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Yup, I agree with QCK. The OP has other issues. Probably the tree.
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post #9 of 26 (permalink) Old 2010-10-20, 01:02 AM
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Poor signal usually causes pixellation, not macroblocking. Pixellation is "hard" and often coloured, while macroblocking is quite different.

http://www.digitalhome.ca/forum/showthread.php?t=17715

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post #10 of 26 (permalink) Old 2010-10-20, 10:33 AM Thread Starter
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What I'm seeing is definitely macroblocking, not pixelation.

When I called Shaw Direct to first report the issue, I was getting 6.5dB ECB (on 299 I think) which they said should be higher. They dispatched a technician, who agreed the ECB seemed a bit low, checked the dish, claimed it was clearing the tree, and said it was probably a weak LNB. He replaced the LNB with little to no effect. At this point, his demeanor changed from helpful and confident he could fix the problem to "I don't notice the artifacts you're talking about, it looks fine to me."

Also, 6.5dB is the lowest I've seen, it usually is in the 7-8 range on HD channels. The dealer setup I watched was in the same range. And the macroblocking persists even when the ECB is in the high 7's. I'm going to try to get some screen caps.
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post #11 of 26 (permalink) Old 2010-10-20, 04:36 PM
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There definitely is macroblocking on many of the HD channels, but only in scenes of rapid movement, not at all times.
A few new channels could pop up in MPEG4 potentially at anytime, but we're still sometime from a full transition. MPEG4 should have minimal effect on PQ.

I think that the PQ is generally fantastic, even better with the 630.

Maybe you are just really sensitive to macroblocking?
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post #12 of 26 (permalink) Old 2010-10-20, 05:43 PM Thread Starter
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There definitely is macroblocking on many of the HD channels, but only in scenes of rapid movement
I watch mostly sports, so most of the important parts are movement. I don't care how realistic Favre's helmet looks when he's in the huddle, I want to see the plays not break up into a blocky mess. But I guess I may have to tolerate it.

Quote:
Maybe you are just really sensitive to macroblocking?
I think I am probably more... intolerant of it, I guess, than most. But several people have watched my setup with me and they could all see it. Some noticed it first, some I had to point it out to. A few agreed that it looked really bad, while others thought I was overreacting. The ones who didn't mind it were mostly the type of people who just don't notice or care about that kind of stuff (picture quality, sound quality; TV's and sound systems generally).

Anyway, thanks to everyone for the responses. It gives me more to think about before I decide whether to stick with Shaw Direct.
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post #13 of 26 (permalink) Old 2010-11-23, 12:55 PM Thread Starter
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Sorry to resurrect a dead thread, but I wanted to post a follow-up here, hopefully it can help others who are trying to make a decision between Shaw Direct and Bell. After watching a lot more of Bell lately, I made the switch.

The Bell picture might not be quite as sharp on still or slow-moving scenes, which is in line with what others have said, but it's close. And there is occasionally some noticeable macroblocking in scenes of fast motion depending on the channel. However, there is much less of it than on Shaw Direct (where it was a constant distraction). On most Bell HD channels, it doesn't seem to happen at all.

My suspicion is that Bell is better at dynamically allocating bandwidth to where it's needed, or to more "important" programming. Even though both services pack about the same number of channels onto each transponder, the big sporting events, for example, tend to look better on Bell.

Overall, I'm happy with the switch. In my opinion, a (possibly, and only very slightly) lower quality picture, but one that's consistent, is preferable to the huge drop in picture quality during motion or scene transitions that are common with Shaw Direct.

As for other factors, SD does seem to have better customer service, while Bell receivers are superior (with the possible exception of Shaw's 630, which I haven't used).
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post #14 of 26 (permalink) Old 2010-11-28, 09:10 AM
 
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Both the TV sets used by the OP are LCD. With football coverage, a stationary camera zooming in is fine but once they switch over to the main camera and start panning, thats when most LCD TV's ability to process the signal hits the wall. Any scene with many sharp vertical lines that's panned quickly with an HD camera will test your LCD limits. Anybody with a plasma won't experience what you're talking about. Maybe overriding a Starchoice receiver output to 720 (like a Bell signal) might help with these situations rather than changing providers.

I know the manager well at my local audio-video store and they will never allow staff to leave a football game feed to all the LCD TV's for obvious reasons. If your a sports fan and have deep pockets to afford the latest 240hz drive LCD's, then go for it. Otherwise, a plasma is worth considering.

Last edited by 57; 2010-11-28 at 11:27 AM. Reason: Unnecessary Quote removed.
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post #15 of 26 (permalink) Old 2012-01-30, 02:38 PM
 
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Unhappy Macroblocking on channel 293

I have a horrible macroblocking issue (where picture gets all blocky)very noticable on shows like Flashpoint channel 293, during rapid movement or quick scene changes. also on other HD channels at times.. I've had the tech out on 2 occasions, and he switched the LNB so signal on all HD is in the high 90's, and the ecb-no number is in the high 7's on these channels... so signal is fine, and with new lnb, why is this still happening so bad.... getting fed up with SD, as I just bought 2 brand new 630's ... is it tv, or hdmi cable or is it a SD thing (i have a 40" Sony LCD)

thanks in advance
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