OTA HD vs Mpeg4 HD

[buzzmc1]

I'll try and politely ask that only people respond with direct experience, watched side by side, etc, which will likely limit my responses a lot.

I hear a lot of people bashing D*'s MPEG4 HD offerings, that OTA looks much better, the MPEG4 feeds are down-rez'd, etc.

While I image the new MPEG4 feeds use less bandwidth, and some might argue more compressed, I would hope that the new mpeg4 technology does a better job w/bandwidth and that what we would think of as "more compression" doesn't really show up all that much, except for the most picky eyes.

I think there's a lot of people that just like to bash for the sake of bashing... If it isn't PERFECT, then it's garbage.

Anyway, on to the meat of the matter ... How does it look? Is there a HUGE difference between OTA vs D*'s MPEG4 HD?

TIA!

-b

[edrock200]

I'm going against your first rule here, as I have not seen a side by side comparison, but I will say if the new HD PVR allows me to chose recording from ATSC or MPEG4 sources I would chose MPEG4 everytime unless the quality was significantly different. The reason being that MPEG4 *should* take up significantly less space on the hard drive than MPEG2, which will allow me to store a lot more HD per GB.

[jcricket]

Of course if DirecTV plans on only using hard drives 2/3 the size of the HR10-250 hard drives in their HD-DVR, then you still end up with the same amount of recording capacity.

I really hope the HR20 ends up with the capability to add drives, or better yet, comes with a 300+GB drive, even with MPG4 using less space. But I'm not holding my breath.

[bpratt]

Several months ago D* had several programs they broadcast in MPEG2 HD that looked as good as OTA HD programs. Since then, they must have reduced the amount of bandwidth they allocate to HD programs because they no longer look as good as OTA.

I believe D* could broadcast either MPEG2 or MPEG4 and match the quality of OTA HD broadcasts if they are willing to allocate enough bandwidth. Whether they will or not is another question.

[coachO]

It is hard to compare OTA and D* as I suspect neither are broadcasting at the proper HD Spec. Having said that, my OTA HD do not look any better or worse than National D* channels.

[edrock200]

Of course if DirecTV plans on only using hard drives 2/3 the size of the HR10-250 hard drives in their HD-DVR, then you still end up with the same amount of recording capacity.

I really hope the HR20 ends up with the capability to add drives, or better yet, comes with a 300+GB drive, even with MPG4 using less space. But I'm not holding my breath.
But unless I'm mistaken the HD PVR's will have both ATSC tuners and mpeg4 tuners, so you will always have a choice of recording mpeg2 or mpeg4 (if locals are available in your area), so no matter how much hard drive space they come with, you'll get more storage chosing mpeg4.

[newsposter]

It is hard to compare OTA and D* as I suspect neither are broadcasting at the proper HD Spec. Having said that, my OTA HD do not look any better or worse than National D* channels.

do you mean that your ABC local OTA in HD is not better than, for example, SciFi on directv? If so, somethings really wrong there. Heck even my OTA SD is so much better than the DTV compressed stuff in philly, that I record survivor OTA and enjoy with the bars and additional disk space used up.

So in philly I can say with certainty that OTA beats DTV on all but the HD sho and hbo that I get

[TyroneShoes]

But unless I'm mistaken the HD PVR's will have both ATSC tuners and mpeg4 tuners, so you will always have a choice of recording mpeg2 or mpeg4 (if locals are available in your area), so no matter how much hard drive space they come with, you'll get more storage chosing mpeg4.
Your conclusion is right, but your facts supporting it are a bit fuzzy. More accurately, the box has ATSC and DVB tuners, and includes both M2 and M4 decoding. A tuner selects and demodulates a modulated carrier to baseband information, and a MPEG decoder converts the information to HD SDI digital video. DAC conversion then either happens in the Tivo (component) or in your display (HDMI). But a tuner is not a decoder, and a decoder is not a tuner. The HR10 does all of this except for the M4 decoding.

[edrock200]

Your conclusion is right, but your facts supporting it are a bit fuzzy. More accurately, the box has ATSC and DVB tuners, and includes both M2 and M4 decoding. A tuner selects and demodulates a modulated carrier to baseband information, and a MPEG decoder converts the information to HD SDI digital video. DAC conversion then either happens in the Tivo (component) or in your display (HDMI). But a tuner is not a decoder, and a decoder is not a tuner. The HR10 does all of this except for the M4 decoding.
Thanks for the clarification. I know that the tuners don't have anything to do with the mpeg decoding but I didn't know the term for the DirecTV tuners (from your post I'm guessing DVB) so I just referred to them as "MPEG4" to differentiate them from the ATSC tuners.

[TyroneShoes]

It's probably easier to think of the PVR as having 4 tuners that are always active, two of them sat and two of them OTA, and two decoders that can each handle both M4 and M2 (assuming the new PVR will have the same basic architecture as the HR10). On the HR10 you can actually "receive" 4 signals at a time, but you can only route the demodulated output of two of them into two paths that write to the HDD, and likewise there are but two paths that can be accessed from the HDD to the buffers, and only one of those can be visible on screen at any time. The key is the internal routing of the various modules that do the different tasks.

Hmmm. Maybe that's not easier.

[edrock200]

lol, yeah I get all that. I understand it, I swear! hehe, thanks for the write up though, its a better way to think of it...4 tuners, 2 sets of 2 decoders and routing.

*edit* sorry for the mini thread-jack.

[darthrsg]

what about the OP? i would like to know as well.

[newsposter]

for those wanting more info about 'why can't tivo record 4 things at once'....see my old thread

http://www.tivocommunity.com/tivo-vb/showthread.php?p=3236429&&#post3236429

It was more than I knew about tuners lol.

ditto about the OP question

[AbMagFab]

Locals are natively MPEG-2. No matter what DirecTV does, any transcoding of the signal will at best be slightly worse. You might not care if you have, say, a 720p TV, but you'll notice on a 1080p TV.

If you can get strong OTA, DirecTV locals are useless (and OTA suffers almost zero rain fade).

[edrock200]

Locals are natively MPEG-2. No matter what DirecTV does, any transcoding of the signal will at best be slightly worse. You might not care if you have, say, a 720p TV, but you'll notice on a 1080p TV.

If you can get strong OTA, DirecTV locals are useless (and OTA suffers almost zero rain fade).
Damn, nothing broadcasts in 1080p yet but we're already dissing the 720p and 1080i sets. lol

[AbMagFab]

First, 1080i is fully resolved on a 1080p set, but not on a 720p set (and arguably not on a 1080i set, since all 1080i sets are analog, and most of those actually do 540p). Most HD is 1080i today, and thus fully realized on a 1080p set.

It has nothing to do with a 1080p source.

Second, any resolution loss will be more visible on a 1080p set. For example, today DirecTV is downrezzing all HD content to a weird mix of 1080i and 720p. However you won't see too much of a difference on a 720p set, but if you have a 1080p set you can see a difference (again, since all the pixels are visible only on a 1080p set).

MPEG-4 transcoding will involve it's own translation losses, even if they keep the full resolution in place (which I doubt they will, IMO). This again will be visible on a 1080p set, but likely less so on a 720p set.

edrock200 - feel free to lag technology, but don't mock what you don't understand.

[edrock200]

edrock200 - feel free to lag technology, but don't mock what you don't understand.
Huh?! I wasn't mocking you at all, just making a joke, relax bro.

That said, abmagfab, I've always respected your opinion and contribution to the boards, but I think you misread my joke as mocking. I understand the difference between 1080p and 1080i and even invested in a 1080p set this holiday (though I'm not convinced they look any better and certain distances.) Regardless, sorry if my post came off as mocking, it was intended to be so.

To the OP, sorry, last threadjack I swear! :)

[dswallow]

Your conclusion is right, but your facts supporting it are a bit fuzzy. More accurately, the box has ATSC and DVB tuners, and includes both M2 and M4 decoding. A tuner selects and demodulates a modulated carrier to baseband information, and a MPEG decoder converts the information to HD SDI digital video. DAC conversion then either happens in the Tivo (component) or in your display (HDMI). But a tuner is not a decoder, and a decoder is not a tuner. The HR10 does all of this except for the M4 decoding.
DVB-S is a standard which is partially followed by Dish Network. DirecTV uses their own "standard" referred to as DSS.

[bdlucas]

Second, any resolution loss will be more visible on a 1080p set.
Sounds like a good reason to save money and not buy a 1080p set. ;)

[Ein]

Sounds like a good reason to save money and not buy a 1080p set. ;)

But, have to plan for the future. (Blu-ray, PS3, etc) :)

[dswallow]

But, have to plan for the future. (Blu-ray, PS3, etc) :)
Too-distant future.

By the time content in HD on DVD is prevalent and affordable, a whole new class of displays will be out.

[dagap]

Several months ago D* had several programs they broadcast in MPEG2 HD that looked as good as OTA HD programs. Since then, they must have reduced the amount of bandwidth they allocate to HD programs because they no longer look as good as OTA.

I believe D* could broadcast either MPEG2 or MPEG4 and match the quality of OTA HD broadcasts if they are willing to allocate enough bandwidth. Whether they will or not is another question.

And therein illustrates the pointlessness of the OP's question.

Are DirecTV's MPEG4 HD locals better/worse/same as OTA HD locals RIGHT NOW? Who cares, unless you also know their plans going forward.

Are they going to keep up the bitrate to ensure everyone's locals are beautiful?

Or are they going to try and cram ever more channels into their limited bandwidth?

[AbMagFab]

Sounds like a good reason to save money and not buy a 1080p set. ;)

Correction - Sounds like a good reason not to rely on DirecTV for your HD, and instead use OTA, cable, FIOS TV, streaming HD from a PC, etc.

There is tons of 1080i HD content available today, more than you could possibly watch. As long as you aren't using DirecTV as your HD provider, a 1080p set provides amazing, amazing picture quality (way above a 720p set). Today.

[AbMagFab]

I understand the difference between 1080p and 1080i and even invested in a 1080p set this holiday (though I'm not convinced they look any better at certain distances.)

Very true. And a point many aren't realizing. Personally, I like to be close to the set, and have a big screen - I want a balance of my field of vision being filled, and minimal head movement required to see the whole screen. If Sony came out with a 70" SXRD (that wasn't the Qualia 006) I would have gotten that.

If you're going to be more than ~8-9 feet from a 60" 1080p set, it's unlikely you'll see much difference from a high quality 720p set of the same size. Your eyes just can't resolve the pixels. Of course if you're buying a 1080p set today, you probably have a 2 year old 720p set, which isn't as high quality as today's higher-end 720p's, so the difference will be greater.

Now that's mathematically speaking. It's also true that the 1080p sets just look better. Sets like the Sony SXRD's are newer technology, with better blacks and richer, deeper colors and textures, and all that (and more) is visible at further viewing distances. So while you might not be able to resolve the pixels, you'll still see a difference (although not quite as earth-shattering as you will much closer).

If you love TV, and have an HD DVR, a 1080p set is a good investment today. You'll want a new one in a couple years when they have 2160p sets anyway... ;) :up:

[buzzmc1]

Can you say scope creep?

All I wanted were the few people fortunate enough to see OTA vs D*'s M4 Locals to post what differences they saw.

Now we're talking about all sorts of things. :(

[TyroneShoes]

DVB-S is a standard which is partially followed by Dish Network. DirecTV uses their own "standard" referred to as DSS.
When's the last time you saw "DSS" in any of DTV's literature? Many years ago, I would think, although it can be found in remnants of old internet sites. DSS is only an acronym for "Direct Satellite Service", which is an all-encompassing term that they were fond of back in the USSB days. DSS does not refer to a transport protocol, as does DVB.

DirecTV originally claimed to be using a "proprietary" protocol back in 1994 when they were using equipment that encoded at a standard somewhat less than MPEG-2, but somewhat improved over MPEG-1. They even referred to it as MPEG-1.5 for a time. Within a few years they had upgraded to all MPEG-2 gear, and I think it was revealed quite some time ago that what they were using by then for a transport protocol was also a variant of DVB, which has numerous flavors. DISH has always used a common variant of DVB, and has always been only MPEG-2. The ASI protocol that many DT OTA stations use to transport compressed digital video from place to place is also a variant of DVB. There is a DVB-C used by CATV, and other variants used by television digital ENG using COFDM modulation, but all of it comes under the umbrella of the DVB standard.

DVB is the standard for transporting digital video that is based on encapsulating MPEG-2 video, and was a replacement for the older analog "-MAC" protocols. It might actually be the only one in common use today. Depending upon the application, other data is added to the transport stream to fit the task at hand. Is DTV still using a "proprietary" protocol? I don't think they are any more, but then I've been fooled by DTV before.

[dswallow]

When's the last time you saw "DSS" in any of DTV's literature? Many years ago, I would think, although it can be found in remnants of old internet sites. DSS is only an acronym for "Direct Satellite Service", which is an all-encompassing term that they were fond of back in the USSB days. DSS does not refer to a transport protocol, as does DVB.

DirecTV originally claimed to be using a "proprietary" protocol back in 1994 when they were using equipment that encoded at a standard somewhat less than MPEG-2, but somewhat improved over MPEG-1. They even referred to it as MPEG-1.5 for a time. Within a few years they had upgraded to all MPEG-2 gear, and I think it was revealed quite some time ago that what they were using by then for a transport protocol was also a variant of DVB, which has numerous flavors. DISH has always used a common variant of DVB, and has always been only MPEG-2. The ASI protocol that many DT OTA stations use to transport compressed digital video from place to place is also a variant of DVB. There is a DVB-C used by CATV, and other variants used by television digital ENG using COFDM modulation, but all of it comes under the umbrella of the DVB standard.

DVB is the standard for transporting digital video that is based on encapsulating MPEG-2 video, and was a replacement for the older analog "-MAC" protocols. It might actually be the only one in common use today. Depending upon the application, other data is added to the transport stream to fit the task at hand. Is DTV still using a "proprietary" protocol? I don't think they are any more, but then I've been fooled by DTV before.
Actually they stopped calling it DSS because of trademark issues; they now just refer to it as DIRECTV's transport stream.

If oyu look through Broadcom (http://www.broadcom.com)'s chipset offerings you'll repeatedly see reference to them supporting "Standard MPEG-2 output in DIRECTV or DVB format"

[TyroneShoes]

...any resolution loss will be more visible on a 1080p set. For example, today DirecTV is downrezzing all HD content to a weird mix of 1080i and 720p. However you won't see too much of a difference on a 720p set, but if you have a 1080p set you can see a difference (again, since all the pixels are visible only on a 1080p set)...
If the resolution used by DTV is 1280x1080, then that is actually the same resolution in the H plane as is 1280x720, and even higher than 1280x720 in the V plane, so any downrezzing of 1920x1080 to 1280x1080 by DTV could not possibly be visible on a display with a native resolution of 1280x720. IOW, you just can't see ANY down-rez effects of "HD Lite" on a native 720p display.

And even if you could, that assumes the rez of the content actually reaches that high. Much of the telecine equipment used for HD transfers today doesn't come anywhere near that kind of resolution, and neither do a lot of the lenses used in acquisition. Resolution is commonly further compromised by production values, and poor cinematographic technique. The brouhaha over HD Lite and 1080p is overblown, much like the hype of audio gear with flat response from 10 Hz to 100,000 Hz designed for rich, middle-aged listeners who can't hear anything above 14K.

But, 1080p sets (especially the Sony SXRD) certainly do look a lot better than the earlier 720p technology, not because of the improved resolution, but rather in spite of it, and due to the many other improvements that have crept into the technology recently. You can't look at potential resolution in a vacuum, because there are too many other factors involved in what a display ends up performing like. Instead, you just have to go to a showroom and figure out what looks good to your eyes, today. Over-analyzing the reasons why doesn't really buy us much.

An example of this muddying of statistical info that should but doesn't mean much, is Beta video quality compared to VHS quality. By pretty much everyone's account, Beta was originally superior to VHS in almost every possible technical way that could manifest visually, even after being dumbed down to match the cassette times of VHS, including resolution, color noise, jitter, color gamut, or what have you. But by the time Beta had been all but abandoned, and the models out there still for sale were based on a system that had had no improvements made to it at all for 3 or 4 years due to no one wanting to invest in improving it, VHS, an admittedly inferior system, actually improved by virtue of numerous tweaks to it and the tape formulations used, to the point where in the end it eclipsed Beta from the point of subjective viewing of PQ, which made VHS a better system. It didn't survive because it was better, it got better because it survived, and Beta didn't.

[Jimmmmbo!]

Hmm, I just wasted my time reading through this thread hoping to find some insight to the original post. Can't anyone just answer the original post directly, even if it's just "No"?

[kepper]

Hmm, I just wasted my time reading through this thread hoping to find some insight to the original post. Can't anyone just answer the original post directly, even if it's just "No"?

I've wondered the same about OTA vs. DTV picture quality. I have limited experience (have had the direct tv HR 10-250 for about three weeks) but this is what I've seen.

Since I live in southern California I get the network west coast HD feed from both D* and from my OTA antenna. My answer to the original poster is- for me, picture quality is sometimes better, sometimes about the same from OTA.

I notice that CBS consistently seems to be quite a bit crisper with an OTA signal than from D*. NBC seems a little better in OTA, especially in detail resolution (like hair). ABC looks pretty much the same from either source.

I was wondering why this might be, and I realize there are multiple factors to account for this. One thing that occurred to me is that CBS only broadcasts digitally on channel 2-1. NBC has two channels, 4-1 and 4-2. ABS has three channels, 7-1, 7-2-, and 7-3. I'm thinking that available bandwidth on the OTA digital carrier may account for some of this difference. D* may have to compress the CBS signal more than they do the ABC signal. This assumes that D* is starting with the same OTA feed of these stations as I get, and I don't know if this is true.

Now, I haven't put a scope on the signal or analyzed the signal electronically. My observations are from watching and having several other people view the programs I've recorded to test this. I have a 32" LCD HDTV so it may be less likely that I see artifacts that someone with a 50" screen would see.

Kevin

[dswallow]

I've wondered the same about OTA vs. DTV picture quality. I have limited experience (have had the direct tv HR 10-250 for about three weeks) but this is what I've seen.
Kevin, people are looking for comparisons between the MPEG4 version of DirecTV's signal; with an HR10-250 you're only seeing the MPEG2 version, which is pretty well recognized to be reduced resolution and highly compressed compared to OTA versions.

[kepper]

Kevin, people are looking for comparisons between the MPEG4 version of DirecTV's signal; with an HR10-250 you're only seeing the MPEG2 version, which is pretty well recognized to be reduced resolution and highly compressed compared to OTA versions.


I should have re-read the thread title before posting. DUH! :)

Kevin

[TyroneShoes]

Hmm, I just wasted my time reading through this thread hoping to find some insight to the original post. Can't anyone just answer the original post directly, even if it's just "No"?
Yes. YOU just wasted your time, not us. The answer is normally in the first 10 posts or so. It's not an easy question, and the answer probably isn't really forthcoming until MPEG-4 implementation becomes common. Actually, asking the question turned out to be a waste of everyone's time, except for the OT conversation it sparked.

Those of us besides yourself, since the answers are already here as best as they're going to be, have moved on to other related topics. That's the way this works. You're free to stop reading this thread at any time, but no one in the current conversation is all that concerned that the rest of us continuing the conversation makes you unhappy, and we really don't think we need to hear about it, so stop wasting OUR time.

[f300v10]

Well I may be the only person that attempts to answer the original question, but here goes. I am in the Atlanta market, and have had D* HD locals for over 2 weeks. We get the Big 4 of ABC, CBS, FOX and NBC. The 2 720P channels look great, I have never be able to detect any difference between OTA and the D*. CBS looks very good most of the time. I have noticed some artifacts when watching football, mostly with blotchy colors in the grass/turf. NBC on the other hand stinks. Lots of artifacts and noise in the picture. Our NBC does multicast weather+ and I think that may have something to due with the poor quality of the D* version.

[Budget_HT]

It's probably easier to think of the PVR as having 4 tuners that are always active, two of them sat and two of them OTA, and two decoders that can each handle both M4 and M2 (assuming the new PVR will have the same basic architecture as the HR10). On the HR10 you can actually "receive" 4 signals at a time, but you can only route the demodulated output of two of them into two paths that write to the HDD, and likewise there are but two paths that can be accessed from the HDD to the buffers, and only one of those can be visible on screen at any time. The key is the internal routing of the various modules that do the different tasks.

Hmmm. Maybe that's not easier.

I thought you were going to say there is only ONE decoder, capable of M2 and M4, which is used when decoding a signal read from the hard drive for playback through the outputs of the machine.

Perhaps I am misunderstanding the role of a decoder in this context?

[Jimmmmbo!]

... and we really don't think we need to hear about it, so stop wasting OUR time.

Huh? Whatever.

The original poster specifically stated "I'll try and politely ask that only people respond with direct experience, watched side by side, etc, which will likely limit my responses a lot.". I simply asked if anyone was willing to try to answer his question. Nice to see f300v10 relate some experience in post #34.

[Jimmmmbo!]

... CBS looks very good most of the time. I have noticed some artifacts when watching football, mostly with blotchy colors in the grass/turf. NBC on the other hand stinks. Lots of artifacts and noise in the picture. Our NBC does multicast weather+ and I think that may have something to due with the poor quality of the D* version.

Interesting. I wonder if D* is downrezzing the 1080i stuff similar to what it does on the national feeds (such as taking 1920 down to 1280). I don't suppose your equipment is able to tell you what the native signal resolution of the source signal is?

[NoThru22]

Yes. YOU just wasted your time, not us. The answer is normally in the first 10 posts or so. It's not an easy question, and the answer probably isn't really forthcoming until MPEG-4 implementation becomes common. Actually, asking the question turned out to be a waste of everyone's time, except for the OT conversation it sparked.

Those of us besides yourself, since the answers are already here as best as they're going to be, have moved on to other related topics. That's the way this works. You're free to stop reading this thread at any time, but no one in the current conversation is all that concerned that the rest of us continuing the conversation makes you unhappy, and we really don't think we need to hear about it, so stop wasting OUR time.
This was an unecessarily mean response to the poster's comment. I was thinking along the same lines and I'm sure a lot of people too timid to post were also thinking the same. I'm sure your tangents are not discouraging anyone with useful information from actually posting, but there was no need to lash out at the poster like that.

That being said, the question hasn't been answered, the answers aren't here, and a lot of people are still curious. This isn't the best place to ask because (1) this is the Tivo forum and the new HD box isn't a Tivo and (2) the existing mpeg4 box isn't even a DVR yet! I will try to search other forums and find an answer to quote or link to.

[NoThru22]

I've searched high and low and haven't found too much useful information. This thread is decent. http://www.avsforum.com/avs-vb/showthread.php?t=501777&page=64&pp=30 It already has some useful information but I'm sure in the future it will be even better.

[Jimmmmbo!]

This isn't the best place to ask because (1) this is the Tivo forum and the new HD box isn't a Tivo and (2) the existing mpeg4 box isn't even a DVR yet! I will try to search other forums and find an answer to quote or link to.
...
This thread is decent. <> It already has some useful information but I'm sure in the future it will be even better.


Thanks for the link, Nothru22. Your two points are well taken, and much more elegantly stated. :up:

[Brewer4]

Well I may be the only person that attempts to answer the original question, but here goes. I am in the Atlanta market, and have had D* HD locals for over 2 weeks. We get the Big 4 of ABC, CBS, FOX and NBC. The 2 720P channels look great, I have never be able to detect any difference between OTA and the D*. CBS looks very good most of the time. I have noticed some artifacts when watching football, mostly with blotchy colors in the grass/turf. NBC on the other hand stinks. Lots of artifacts and noise in the picture. Our NBC does multicast weather+ and I think that may have something to due with the poor quality of the D* version.

Thanks for being the only one that answered the question. It really was a simple one that asked if you could subjectively tell the difference if you had them side by side. I only need D* for ABC which is 90% OTA for me but is the weakest signal so I would like the D* sat feed for that one. The rest, I will continue to use OTA. Still a very interesting question.

[f300v10]

Thanks for being the only one that answered the question. It really was a simple one that asked if you could subjectively tell the difference if you had them side by side. I only need D* for ABC which is 90% OTA for me but is the weakest signal so I would like the D* sat feed for that one. The rest, I will continue to use OTA. Still a very interesting question.

No problem. I have not watched that much on the H20, since I have the HR10-250 and get pretty good OTA reception, unless the wind is blowing and then it sucks (dynamic multipath caused by lots of tall trees). That is the main reason I got the H20, for a backup when it is windy. I checked out Leno last night on the H20, and to my supprise, it looked real good on the D* local HD channel. I will try to watch more tonight, maybe D* has adjusted something to improve the Atlanta NBC.

[DeDondeEs]

Yes. YOU just wasted your time, not us. The answer is normally in the first 10 posts or so. It's not an easy question, and the answer probably isn't really forthcoming until MPEG-4 implementation becomes common. Actually, asking the question turned out to be a waste of everyone's time, except for the OT conversation it sparked.

Those of us besides yourself, since the answers are already here as best as they're going to be, have moved on to other related topics. That's the way this works. You're free to stop reading this thread at any time, but no one in the current conversation is all that concerned that the rest of us continuing the conversation makes you unhappy, and we really don't think we need to hear about it, so stop wasting OUR time.

Actually anyone posting about MPEG-4 is on the wrong website since Tivo's don't record in MPEG-4 and this is the Tivo Community. Read the sticky at the top of this forum. The AVS forum has plenty of great posts on this topic.

[dswallow]

Actually anyone posting about MPEG-4 is on the wrong website since Tivo's don't record in MPEG-4 and this is the Tivo Community. Read the sticky at the top of this forum. The AVS forum has plenty of great posts on this topic.
Except it'd be fair game because the HR10-250 records what they're comparing it against.

[TyroneShoes]

This was an unecessarily mean response to the poster's comment. I was thinking along the same lines and I'm sure a lot of people too timid to post were also thinking the same. I'm sure your tangents are not discouraging anyone with useful information from actually posting, but there was no need to lash out at the poster like that...
OK, you have made a good point. And I apologize for saying exactly what everyone else was thinking. Anyone offended, let me know how I can make it up to you. Offending folks who have offended me was not my intent, it was more to stick up for the natural evolution of forum threads. In other words, it was me saying "cut me a break...can't you see we're trying to have a conversation here?". But I'm a work in progress, and I sometimes have little tolerance for those with little tolerance. No excuse for it...I'll simply count to ten from now on.

[TyroneShoes]

I thought you were going to say there is only ONE decoder, capable of M2 and M4, which is used when decoding a signal read from the hard drive for playback through the outputs of the machine.

Perhaps I am misunderstanding the role of a decoder in this context?
The MPEG decoder accepts an MPEG-encoded data stream from the hard drive and converts it into SDI video (HD SDI in this case), which is real-time uncompressed digital video. Missing information discarded in the encoding process is replicated according to a set of rules established by the encoding algorithm, essentially making educated guesses, and filling in the gaps created by encoding, hopefully cleverly enough so that we won't notice that it might actually be slightly different from the original encoded information.

That said, I think there must be at least two decoders in any 2-channel PVR. I don't know of decoders that can decode multiple streams simultaneously, at least at the consumer level. For a box capable of both M4 and M2, one decoder also capable of both would be needed for each decoded video stream, or possibly two M2 and two M4 decoders.

[Phantom Gremlin]

Why do people think there need to be two MPEG decoders? Decoders are only used for viewing a video stream. So unless the PVR can simultaneously display multiple video streams it doesn't need multiple decoders. Or do you think that you are flipping between multiple streams too quickly for the PVR software to reprogram a single decoder quickly enough to keep up?

BTW, apparently there is a cable HD box that can simultaneously "record to VCR" a different stream than it is displaying. That box would need two decoders.

[Budget_HT]

I don't know what the new MPEG-4-capable HD DVR will bring, but I do know that each of my SD and HD DirecTV DVRs with TiVo only show one stream at a time, thus they must be limited to a single decoder if I understand this correctly.

They can record two and playback a prerecorded third, but no matter what, they only output one at a time.

[bdlucas]

So unless the PVR can simultaneously display multiple video streams it doesn't need multiple decoders.
I think you are correct; there's no need for more than one MPEG-2 decoder in the HR10-250.

[bdlucas]

I don't know who's at fault for the backlevel and slow software on our HD TiVo's, nor do I think anyone posting to this forum really knows (or if they did their employer probably wouldn't be happy about their publicizing the information). I can tell you from first-hand experience that the realities of bringing a hardware/software product to market can cause all manner of anomalies that are baffling to an outsider and correspondingly frustrating to someone involved in the process. The explanation is usually complicated, with plenty of blame to go around.

Here's a hypothetical scenario (drawn very loosely from personal experience) to illustrate what I mean. I am not suggesting that this is what happened, but rather only illustrating the kind of thing that can produce strange results in the 20/20 hindsight of us couch potatoes. So please don't debate the following as if it were a theory of what actually happened with TiVo and DirecTV!

Suppose a product is planned for release on a particular date. The software is contracted out, commitments are made, resources are allocated to develop the software, and the software is ready on the planned release date as per contract. But suppose that meanwhile for whatever reason - market changes, strategic changes, management/ownership changes, poor planning, unforseen difficulties designing and producing the hardware - the product release date is pushed out. Suppose even worse it goes into a month-by-month slip, with a constant stream of new target release dates such that at no point does it appear there is enough time or resources to change the software plan. Result is when it finally goes out it has old software. In this scenario the software vendor has done their job, and it's even possible that the worst the product owner has done is to fail to foresee the unforseeable, depending on what caused the product slip.

Again, the point is not that I think this is what happened, but rather that what actually happened is most likely more complicated than it might seem and largely unknown to us.

[dswallow]

Again, the point is not that I think this is what happened, but rather that what actually happened is most likely more complicated than it might seem and largely unknown to us.
I believe it was shown running the 6.x software at CES last year.

Not that it matters much; obviously sooner or later it's a dead end product anyway. It's serving its purpose well for the time being, even if sometimes a little slow on the menus.

[bdlucas]

I believe it was shown running the 6.x software at CES last year.
This gives us but a tiny window into what's going on. I can attest from personal experience that trade show demos bear only a loose relationship to products. (Reminds me of the old joke about the guy who dies, and is given a choice between heaven and hell. He's shown a video of hell: dancing, wine, partying, a generally good time. He's shown pictures of heaven: peaceful enough but boring. Of course he chooses hell. But on arrival he finds something quite different: fire, brimstone, eternal suffering. What's up, he asks? Where's the party? Oh, comes the answer; you must have seen our demo. :))

it's a dead end product anyway
Quite possibly one of the complicating factors in the story. Resources are only reluctantly committed to dead-end products. DirecTV may even have known before its release that it was a dead-end product, and TiVo may have know that it was a dead-end relationship.

[newsposter]

All I wanted were the few people fortunate enough to see OTA vs D*'s M4 Locals to post what differences they saw.

Now we're talking about all sorts of things. :(

Can anyone else answer this now that we are closer to the hd dvr than ever? :)

[AbMagFab]

Can anyone else answer this now that we are closer to the hd dvr than ever? :)

By definition, we are always closer than ever. But that means we're still 6-12 months away.

[newsposter]

Now I have another 'weird' question for you. Are the SD programs any better than in MPEG2 when watched on the HD channel? I prefer to watch SD stuff OTA with bars as the colors and textures are so much better than directvs locals. So I was wondering, did the SD locals programs improve when you watch them on the directv HD channel and get the same results as i'm getting today with OTA SD?

hope i was clear..gets confusing with all those abbreviations

[kdonnel]

I am in the Atlanta market, and have had D* HD locals for over 2 weeks.

Are they actually watchable? Two of my neighbors and another friend have all upgraded to the H20. According to all three of them the HD locals from DirecTv are all but unwatchable.

They have all had DirecTV out to replace the LNB, run new cabling, and repoint the new dish. In each case the picture still pixelates all the time.

They have been told it was their TV, it is a software problem DirecTV is working on, and that DirecTV has no idea why it does not work but they are trying to figure out why.

[jcricket]

To answer the poster's original question, I think Earl commented over at dbstalk.com that he couldn't see the difference between the MPG4 HD Satellite locals and OTA HD locals (MPG2) viewed on the on the H20 receiver (not a DVR, but that doesn't matter).

I can certainly tell the difference between SD programs on my OTA local channels and MPG2 Satellite versions of those local channels (on my HR10-250). However, when I compare general quality of Discovery HD and an OTA local, they appear about the same. Quality of programming itself is a different matter :)

I'm willing to bet that the MPG4 HD locals will be high enough quality that it will be a good-enough solution for most people when compared to having to deal with an OTA antenna and uncertain reception. There will continue to be some people who can see a difference, either because they just hate the idea of re-compression or have some uber high-end setup where differences are obvious. Most of us will be happy to get all our programming via the satellite and go back to not having to deal with the whole antenna situation.

Whether or not the HR20 is better than the HR10 is another matter too.

[spdntckt]

I cant compare the HD DVRs.. but i can tell you that as a technology, a 15-18mb/s MPEG 2 picture is better - by far - than a 10mb/s H.264 MPEG4 picture - at least on the encoders ive used..
Reference /input was an 8 bit uncompressed 1920x1080i signal.. approx 1000mb/s bandwidth
display device is a sony VPL-VW100 1920x1080i projector - 1080p capable. Input was

Reference signal was than passed into a few encoders, the best was Apple's compressor which was configured for MPEG2- open GOP of 8, data rate 18mb/s - 1280x720p - this is test case 1

test case 2 was the same Apple compressor, configured for H.264 at 10mb/s, MPEG4, resolution 1280x720p

When viewed on the large (7') screen, everyone i showed it to could see the difference. MPEG2 was clearly the 'better picture'

MPEG4 is 'damn good' considering it is almost 1/2 the bandwidth.. but for overall picture quality a high b/w MPEG2 source is better.. most of the encoder videophiles agree that high b/w mpeg2 is better than mid b/w MPEG4.. however, bit for bit.. MPEG4 will be better (eg. you cant compare a 10mb/s MPEG2 and MPEG4 source.. mpeg2 is only better at higher bit rates).

[bdlucas]

as a technology, a 15-18mb/s MPEG 2 picture is better - by far - than a 10mb/s H.264 MPEG4 picture - at least on the encoders ive used.
I think the last bit is the key, since the quality of the encoder is critical to the results. Reports I've seen say that both by objective and subject tests, MPEG-4 H.264 is capable of equally quality to MPEG-2 about half the bitrate. Reports on this forum comparing OTA MPEG2 to DirectTV MPEG4 seem to agree.

[SpankyInChicago]

I think the last bit is the key, since the quality of the encoder is critical to the results. Reports I've seen say that both by objective and subject tests, MPEG-4 H.264 is capable of equally quality to MPEG-2 about half the bitrate. Reports on this forum comparing OTA MPEG2 to DirectTV MPEG4 seem to agree.

Well, unless DirecTV is getting the raw SDI datastream from the OTA station (unlikely), what DirecTV is actually doing in recompressing an already compressed picture.

If DirecTV is getting the same MPEG2 stream from the OTA station that we can pick up with our OTA antenna, it would be impossible for any signal sent by DirecTV to us over the satellite, whether further encoded with MPEG2 or reencoded with MPEG4 to look as good as the original OTA signal.

Further lossy compressing an already lossy compressed signal always looks worse than the original lossy compressed signal regardless of the secondary lossy compression method used.

[newsposter]

To answer the poster's original question, I think Earl commented over at dbstalk.com that he couldn't see the difference between the MPG4 HD Satellite locals and OTA HD locals (MPG2) viewed on the on the H20 receiver (not a DVR, but that doesn't matter).

.

Ok so I guess i can infer that the SD pictures (90% of what is on in any given day) when watched through the Mpeg4 HD channel, will look just as good as when I watch the SD stuff OTA then? And also they will look better than the SD locals on DTV too right?

[newsposter]

. but i can tell you that as a technology, a 15-18mb/s MPEG 2 picture is better - by far - than a 10mb/s H.264 MPEG4 picture - at least on the encoders ive used..

MPEG4 is 'damn good' considering it is almost 1/2 the bandwidth.. but for overall picture quality a high b/w MPEG2 source is better.. most of the encoder videophiles agree that high b/w mpeg2 is better than mid b/w MPEG4.. however, bit for bit.. MPEG4 will be better (eg. you cant compare a 10mb/s MPEG2 and MPEG4 source.. mpeg2 is only better at higher bit rates).

interesting points indeed. I guess the one certainty that it seems everyone will agree on is that a perfect OTA signal is by definition the highest possible quality we can ever receive since there is no 'middleman' to deal with. Can anyone refute that?

I followed most of the 2nd paragraph above except when you said however, bit for bit.. MPEG4 will be better Is it because a 10mb mpeg2 is like a 5 mb mpeg4 but if the mpeg4 is 10mb (same size as mpeg2) then it's really 2x the quality of mpeg2 and thus equivalent to a 20mb mpeg4 stream? ---can u tell im lost?

[bdlucas]

Well, unless DirecTV is getting the raw SDI datastream from the OTA station (unlikely), what DirecTV is actually doing in recompressing an already compressed picture.

If DirecTV is getting the same MPEG2 stream from the OTA station that we can pick up with our OTA antenna, it would be impossible for any signal sent by DirecTV to us over the satellite, whether further encoded with MPEG2 or reencoded with MPEG4 to look as good as the original OTA signal.

Further lossy compressing an already lossy compressed signal always looks worse than the original lossy compressed signal regardless of the secondary lossy compression method used.
That's true (although it wasn't the issue I was addressing in my posting that you quoted nor the issue that the person I was responding to was talking about).

However, it is possible that the re-compressed signal will be only negligibly worse, that is, that the difference won't be noticeable. As an analogy, if you open a JPEG compressed image and edit it and then re-save it, in theory you've lost some quality, but in practice you often won't see a difference unless you do it many times. Some are reporting that they don't see a difference between the re-compressed DirecTV signal and OTA.

[newsposter]

Well, unless DirecTV is getting the raw SDI datastream from the OTA station (unlikely), what DirecTV is actually doing in recompressing an already compressed picture.

If DirecTV is getting the same MPEG2 stream from the OTA station that we can pick up with our OTA antenna, it would be impossible for any signal sent by DirecTV to us over the satellite, whether further encoded with MPEG2 or reencoded with MPEG4 to look as good as the original OTA signal.

Further lossy compressing an already lossy compressed signal always looks worse than the original lossy compressed signal regardless of the secondary lossy compression method used.

You just answered my question above, thanks....Can you tell i'm reading posts in order instead of all at once :) Also Thanks for the affirmation in my decision to spend over 400 bucks to get my OTA in perfect working order. I probably would be unhappy with the directv HD signals for locals given the facts above in these posts(and problems i've read about in the HR20 with pixels). Though I'm sure anyone going from mpeg2 directly to mpeg4 without ever seeing an antenna outside is probably going to be happy. But something tells me going from ota to mpeg 4 i would not be very satisfied.

The statement that even a perfect signal gets worse when you do 'anything' to it is really the key here. The virgin signal from a tower indeed sounds like the best thing in the world.

[SpankyInChicago]

interesting points indeed. I guess the one certainty that it seems everyone will agree on is that a perfect OTA signal is by definition the highest possible quality we can ever receive since there is no 'middleman' to deal with. Can anyone refute that?


In practice this certainly can't be refuted. In theory it COULD be possible to receive a better signal than OTA, but this would require that DirecTV (or the cable company) get access to the OTA signal before it has been compressed from the original uncompressed HD signal into the MPEG to ready for air signal. Of course on a network-based show sent to a local affiliate the show might already have been compressed prior to being sent to the local affiliate.


I followed most of the 2nd paragraph above except when you said Is it because a 10mb mpeg2 is like a 5 mb mpeg4 but if the mpeg4 is 10mb (same size as mpeg2) then it's really 2x the quality of mpeg2 and thus equivalent to a 20mb mpeg4 stream? ---can u tell im lost?

Imagine an input stream X. If you were to compress X using MPEG2 at Y bit rate and compare it to X compressed using MPEG4 at Y bit rate, the resultant MPEG4 stream would look superior to the resultant MPEG2 stream. In other words, all things being equal (input source, output bit rate, encoder quality, etc.) MPEG4 results in superior picture quality than MPEG2.

[SpankyInChicago]

That's true (although it wasn't the issue I was addressing in my posting that you quoted nor the issue that the person I was responding to was talking about).

However, it is possible that the re-compressed signal will be only negligibly worse, that is, that the difference won't be noticeable. As an analogy, if you open a JPEG compressed image and edit it and then re-save it, in theory you've lost some quality, but in practice you often won't see a difference unless you do it many times. Some are reporting that they don't see a difference between the re-compressed DirecTV signal and OTA.

Sorry that I misundertood your the intent of your original post.

I will say, however, that if you've worked with many JPEG images it doesn't take much to make a RAW image from your digital cam look bad by a few iterations through JPEG. And the problems obviously manifest themselves much quicker with moving images as opposed to still images.

But, you are correct. It would be possible for a recompressed image to be visually the same quality as the original compressed image, though, obviously, it would not technically be the same quality. The factors, of course, are wildly varying, and the bottom line will always remain that OTA MPEG2 is likely always going to be the "best" picture quality.

[newsposter]

Some are reporting that they don't see a difference between the re-compressed DirecTV signal and OTA.

Isn't there some way the geeks can measure the signal coming into our homes? :)

[bdlucas]

Isn't there some way the geeks can measure the signal coming into our homes? :)
There are are several. Two general categories:

1. Subjective: which looks better, A or B? Do you see a difference between A and B? In some sense this is the only relevant measure. Ideal is a double-blind test under controlled viewing conditions. Anecdotal reports here and elsewhere are suggestive but should be viewed with skepticism.

2. Objective: for example, PSNR, which is essentially a measure of the average pixel-by-pixel numerical difference between corresponding R, G, and B values.

On both measures MPEG-4 as a technology has been shown to be capable (given a good encoder) of the same quality as MPEG-2 at about half the bitrate of MPEG-2. But as the discussion here indicates that's only part of the story as to whether MPEG-4 from DirectTV will look as good as OTA MPEG-2.

[jcricket]

Ok so I guess i can infer that the SD pictures (90% of what is on in any given day) when watched through the Mpeg4 HD channel, will look just as good as when I watch the SD stuff OTA then? And also they will look better than the SD locals on DTV too right?
Theoretically yes. But (someone more technical can correct me if I'm wrong) it's possible D* could compress the MPG4 feeds as much as they do the MPG2 feeds, resulting in crappy SD, HD, etc.

Assuming D* allocates enough bandwidth to the MPG4 feeds, HD should look close to as good as OTA HD, and SD program broadcast over those MPG4 feeds should look close to as good as OTA SD.

Your SD that you get via the MPG2 feeds from the existing satellites will probably still look like crap until D* stops compressing so much (i.e. hell freezing over). What's more likely is that as channels start broadcasting in HD, D* will put up MPG4 feeds of those channels, which they will hopefully keep enough bandwidth for.

I think that's why so many people here are iffy on the idea of getting HD channels (esp. locals) from D*. They worry that even though they're in HD, and being broadcast with MPG4 compression (saving 1/2 the bandwidth), D* will still find itself crunched and compress things even more.

[newsposter]

Everyone thanks for the insight. it's exactly what I've been looking for and explained in terms I can understand. I also know a lot more people will be interested in the content of this thread.

One thing that took me longest to understand is post 65 , last paragraph. But I think I got it down to: if the same picture is crammed into the same space, mpeg4, by definition, is better than mpeg2. It's appears the code/mechanism or whatever, produces a better picture even with the same amount of space taken up. (plz correct me if i'm wrong :))

Also while OTA is a more 'virgin' signal, you may not notice the difference with MPEG4 unless you are a discriminating viewer. So the picture can be technically, but not visually, superior.

[bdlucas]

if the same picture is crammed into the same space, mpeg4, by definition, is better than mpeg2. It's appears the code/mechanism or whatever, produces a better picture even with the same amount of space taken up.
That's right, assuming a high-quality encoder. This matters because MPEG-4 (as does MPEG-2) owes much of its efficiency to detecting moving scene elements and encoding them by sending instructions to the decoder that say "take that part of the image from the previous frame, move it over here, and apply this correction". There's no single correct way to do this encoding, but the better the encoder is at finding such moving scene elements the smaller the "corrections" will have to be and so the less space the encoding takes up. Much of the improvement in MPEG-4 over MPEG-2 is due to a more flexible vocabulary (encoding) for describing moving scene elements.

Since for a given encoding scheme (e.g. MPEG-2 or MPEG-4) there's a tradeoff between image quality and amount of space taken up, the flip side of your statement is that the same image quality can be achieved by MPEG-4 as can by MPEG-2 while using "less space" (fewer bits) for the MPEG-4 encoding, by about a factor of two.

[AbMagFab]

Also while OTA is a more 'virgin' signal, you may not notice the difference with MPEG4 unless you are a discriminating viewer. So the picture can be technically, but not visually, superior.

Not entirely true. What people are forgetting is that TV's are getting better every day.

The newest round released late last year support the full 1080i resolution. This means that HD compression is more obvious.

It's analogous to how SD on an HD TV looks worse than on a non-HD TV. Well, compressed HD on a full 1080i TV looks worse than on a 720/768p HD TV (which is what most people have today).

I've got a 1080p 60" Sony XBR1, and DirecTV HD compression is extremely noticable. I haven't cancelled my HD package yet (as many people have pointed out, we don't have an option), but the HD picture quality is poor on a 60" (or greater) 1080p set. (It's probably not as noticable on a 720/768p set).

It more than a "discriminating viewer", it's what you're watching on.

[newsposter]

so how good a pic am i getting on my 2005 1080i crt rptv? :) I'm pretty happy but maybe i dont know what i dont know.

[AbMagFab]

so how good a pic am i getting on my 2005 1080i crt rptv? :) I'm pretty happy but maybe i dont know what i dont know.

CRT's are analog, and so it's a very different picture. Generally speaking, the newer digital 1080i's, especially the SXRD/D-ILA's are considered better, perhaps much better than the CRT's.

The CRT's weren't really 1080i, in that they weren't displaying every pixel. The digital 1080i's display each and every pixel. But to some, this is an album/CD debate in terms of the overall experience.

Bottom line - the 1080i CRT's won't show the picture issues as much as the 1080i digital sets, but that's because they don't have as detailed a picture.

More to the point, the providers need to stop messing with the pictures. FIOS, at least in my area, is supposed to have an amazing picture, substantially better than DirecTV (see reports on AVS).

(Now let the analog freaks come and flame away...)

[newsposter]

CRT's are analog, and so it's a very different picture. Generally speaking, the newer digital 1080i's, especially the SXRD/D-ILA's are considered better, perhaps much better than the CRT's.



They darn well better be better for 2-3X what i paid for mine! Until sxrd or plasma is around 1800-2000, no way would I spend more on the digital displays until all the world is in HD.

SD was paramount concern for me (read the horror stories of lcd and plasma trying to get a decent pic) and I think the general consensus is that unless you have sxrd or other high end gear, SD sucks on digital tvs. So I went with a nice big crt at a cheaper price than i paid 8 yrs ago with my other big screen. Love technology!

Plus the HDtivo does a nice job on SD when it's kicked up to 1080. Very noticable difference even to my wife when I forget to flip the switch from 480i (burning dvds)

[TyroneShoes]

Not entirely true. What people are forgetting is that TV's are getting better every day.

The newest round released late last year support the full 1080i resolution. This means that HD compression is more obvious.

It's analogous to how SD on an HD TV looks worse than on a non-HD TV. Well, compressed HD on a full 1080i TV looks worse than on a 720/768p HD TV (which is what most people have today)...I'm afraid that is a false analogy. Digital artifacts and native resolution are two very different things that have little in common with each other and very little effect on each other. Increasing the native rez to 1080i will not necessarily make compression artifacts more visible than at lower native resolutions, and for the most part, does not do that in the least. This is due to the nature of DT compression artifacts, which are usually limited to pixellation and mosquito noise for DT reception, and primarily to pixellation on motion.

If native resolution is the variable, then we have to look at how resolution might affect such artifacts. This applies to both types of artifacts, but I will use pixellation as an example. This sort of artifact manifests as blocks of pixels remaining on the screen for a split second longer than they should, as the decoder struggles to update them with new information in a timely manner. If an 8x8 pixel block is visible longer than it should be, that will be just as noticeable or visible when displayed on the screen as 1 to 1 from a 1080i or even a 1080p image, as it might when reinterpolated to 720 or 768 in the display.

To be masked significantly, an artifact 8 pixels high or wide would have to be smaller than either 1080 native rez, 768 native rez, or 720 native rez can resolve, which means the native rez of the display would have to be 1/8th of 1080, or 240x135, or lower, for the artifact to not be resolved. Since even 1280x720 is orders of magnitude more resolved than 240x135, that would have no more effect on masking 8x8 macroblocks than 1080p rez, other than making the edges of the macroblocks a bit less defined, which is about as signifcant as determining what side someone's hair is normally parted on while they're standing in a hurricane.

This is the exact flip side of the argument that 1080p resolution will not provide more actual visible resolution for an image than 720p will, if that image is not a high-resolution image in the first place. Out of focus? Bad telecine transfer? Cheap lens? 480i master? higher native display rez provides no advantage whatsoever, just like no HD display can make a NTSC copy of a classic Seinfeld ep ever look like HD resolution, no matter how much he might be the "master of his own domain".

Bottom line, assuming insignificant resolution differences will make digital compression artifacts significantly more or less visible is a flawed assumption, and comparing this to the difference between resolution of images on SD or HD displays is like comparing apples to oranges.

[AbMagFab]

Math confuses me... And what looks good is what matters, not what a bunch of numbers say.

I have a 768p 50" HD TV, and a 1080p 60" HD TV. The DirecTV HD looks okay on the 768p, and looks bad on the 1080p. The OTA HD looks great on both.

Ergo, the better the TV, the more you'll see the effects of the DirecTV compression.

Remember, DirecTV is recompressing a 1080i signal into something slightly more than a 720p signal. Even if we ignore the picture degredation, the reality is you won't notice much difference on a 720/768p set since it just won't resolve the picture in enough detail.

However, a 1080p set will resolve beyond what DirecTV is compressing. So, when comparing a DirecTV HD signal with its OTA counterpart, the difference is plainly visible - DirecTV is ruining the HD picture.

And most of the people posting likely have a 720/768p set, so they won't see much of a difference. BUT, that doesn't mean there isn't a difference. And as more people upgrade to 1080p sets, they will see what the rest of us see - a lousy HD picture from DirecTV, and great HD pictures OTA.

[dswallow]

Math confuses me... And what looks good is what matters, not what a bunch of numbers say.

I have a 768p 50" HD TV, and a 1080p 60" HD TV. The DirecTV HD looks okay on the 768p, and looks bad on the 1080p. The OTA HD looks great on both.

Ergo, the better the TV, the more you'll see the effects of the DirecTV compression.

Remember, DirecTV is recompressing a 1080i signal into something slightly more than a 720p signal. Even if we ignore the picture degredation, the reality is you won't notice much difference on a 720/768p set since it just won't resolve the picture in enough detail.

However, a 1080p set will resolve beyond what DirecTV is compressing. So, when comparing a DirecTV HD signal with its OTA counterpart, the difference is plainly visible - DirecTV is ruining the HD picture.

And most of the people posting likely have a 720/768p set, so they won't see much of a difference. BUT, that doesn't mean there isn't a difference. And as more people upgrade to 1080p sets, they will see what the rest of us see - a lousy HD picture from DirecTV, and great HD pictures OTA.
Unfortunately there's so many ways for the display owner to screw things up you can't always blame the bad picture on the source material; they need to come up with some automatic ways to calibrate the display to a standard. :)

[AbMagFab]

Unfortunately there's so many ways for the display owner to screw things up you can't always blame the bad picture on the source material; they need to come up with some automatic ways to calibrate the display to a standard. :)

Quite true. I, of course, believe my sets to be well calbrated.

Even so, if the OTA picture looks perfect, and the DirecTV picture looks poor, that has little to do with the calibration, since I'm viewing them on the same input.

I have a great picture with OTA on both sets. I have a lousy picture from DirecTV HD on the better set, compared to the OTA picture. Ergo, the DirecTV picture looks worse, independent of calibration.

Unless you know of some magic calibration that would only effect the DirecTV picture... ;)

[dswallow]

Quite true. I, of course, believe my sets to be well calbrated.

Even so, if the OTA picture looks perfect, and the DirecTV picture looks poor, that has little to do with the calibration, since I'm viewing them on the same input.

I have a great picture with OTA on both sets. I have a lousy picture from DirecTV HD on the better set, compared to the OTA picture. Ergo, the DirecTV picture looks worse, independent of calibration.

Unless you know of some magic calibration that would only effect the DirecTV picture... ;)
THe most obvious thing from over-compression is the blockiness o of darks, so obviously raising brightness is aesthetically harmful. Unfortunately if you've got it calibrated properly for OTA HD over the same input, there's not a lot you really can do.

It could be worse, though... you could live in one of those markets where every affiliate sends out several subchannels. ;)

[AbMagFab]

THe most obvious thing from over-compression is the blockiness o of darks, so obviously raising brightness is aesthetically harmful. Unfortunately if you've got it calibrated properly for OTA HD over the same input, there's not a lot you really can do.

It could be worse, though... you could live in one of those markets where every affiliate sends out several subchannels. ;)

Yeah, DC isn't too bad. ABC, NBC, and CBS all have some goofy weather subchannel, but it seems to be relatively low bandwidth.

Except for UPN (which is still in test mode), all 5 nets look great in this area. CBS has overall the best look and manages to screw up the least. Fox looks great, but is only 720p (which is noticable), but they also screw up very little. ABC looks great when it's working, but they have lots of transmitter problems (hiccups and such). NBC looks okay, but they seem to forget to switch to HD about 20% of the time. I don't watch much WB, but when I do, it's generally very good.

So overall, a good set of OTA networks here.

And I agree with one of your other posts - give me OTA HD, and I could almost live without most of the other channels. I pay for them all because I like the options, but if DirecTV keeps raising rates, and screwing the quality, I'll lower my package just to make a point, and because it's simply not worth it.

[TyroneShoes]

...DirecTV HD looks okay on the 768p, and looks bad on the 1080p. The OTA HD looks great on both.

Ergo, the better the TV, the more you'll see the effects of the DirecTV compression...
You are confusing artifacts from compression with reinterpolation. What DirecTV is doing to 1920x1080 signals is reinterpolating them to 1280x1080. Yes, that implies that they are decompressing and recompressing the signal to accomplish that, but no, it does not imply that this means that such a process will add more compression artifacts. It takes severe compression to create visible artifacts, and this is not a severe compression process.

What you might see on a 1080p set vs. a 768 or 720 set is a difference in resolution, but only if the original source material was fully resolved at 1080p to begin with, and very little 1080i source material currently is. But any compression artifacts that might be added in DTV's process would be negligible and very likely invisible. In fact, it can be argued that a lower resolution might actually provide fewer digital artifacts because it takes fewer bits to transmit, making bit starving less likely, all else being equal, and that is the very reason DTV does this in the first place...it is a tradeoff in resolution for equivalent artifacting at a lower bandwidth.

Assuming that because content looks worse on your 1080 set might be due to increased artifacts from DTV's reinterpolation process is just ludicrous. There are no more artifacts to see. The only difference is in the native resolution of your set and the transmitted resolution of DTV vs. OTA.

Math hurts my brain too, but a 1920x1080 set will display the DTV image at 1280x1080, and a 768 set will display it at 1280x768, which means resolution in the H rez should appear the same on both, the difference being in the V dimension only, which is a difference in the sets, and NOT in the DTV original image as compared to OTA (1080 reinterpolated to 768 is the same for both).

Not only that but the effective perceived vertical resolution of 1080i tops out at about 756 for all raster-scanned images due to Kell factor alone (0.7X1080), including all images shot with a camera or telecined over from film, so a 768 V rez will not really display anything visibly different than a set with 1080 capability. And you have to be sitting less than 8 feet away from a 60" set for your eyes to resolve full 1920x1080 in the first place, assuming that resolution is even there in the first place, which it normally isn't.

A 1920x1080 set will display OTA at 1920x1080, and a 768 set will display it at 1366x768, so the difference in the V dimension is again exactly the same between sets as it was for DTV, and the difference between interpolating 1920 to 1280 and interpolating 1920 to 1366, the difference in the V dimension between sets, is very slim, and only for fully resolved images, which are rare.

And none of that difference has anything at all to do with the amount of digital compression artifacts. That is an entirely different issue. If one set looks better than the other, you can rule out the amount of artifacts from the source content and you can all but rule out any reduced resolution. With different displays, there can be any number of other factors that could be creating a perceived difference, but I guess you can latch on to whatever superstitious theory you want to. You just won't have any proof or even acceptable theory to back it up.

[AbMagFab]

But any compression artifacts that might be added in DTV's process would be negligible and very likely invisible. In fact, it can be argued that a lower resolution might actually provide fewer digital artifacts because it takes fewer bits to transmit, making bit starving less likely, all else being equal, and that is the very reason DTV does this in the first place...it is a tradeoff in resolution for equivalent artifacting at a lower bandwidth.

Assuming that because content looks worse on your 1080 set might be due to increased artifacts from DTV's reinterpolation process is just ludicrous. There are no more artifacts to see. The only difference is in the native resolution of your set and the transmitted resolution of DTV vs. OTA.

I appreciate the theory, but my eyes tell me something else. Take the specific example of OTA on my 1080p vs. the same content via DirecTV. OTA looks much much better. I'm not talking artifacts, I'm saying the picture looks better.

When DirecTV reduces the resolution, they can't simply pluck out pixels, they need to do something to the picture to smooth out where they reduced the resolution. That means they are introducing stuff into the picture that wasn't there to begin with. And in doing so, they are making the picture look worse, much worse (IMO).

Math hurts my brain too, but a 1920x1080 set will display the DTV image at 1280x1080, and a 768 set will display it at 1280x768, which means resolution in the H rez should appear the same on both, the difference being in the V dimension only, which is a difference in the sets, and NOT in the DTV original image as compared to OTA (1080 reinterpolated to 768 is the same for both).

I think I get your point, but it's not entirely true. The 1080p set (it's digital) upconverts everything to 1920x1080. But that's irrelevent since the HD Tivo (and any HD receiver) will have to upconvert it first (or at a minimum, convert it to a standard signal). So my TV is not showing a 1280x1080 picture, it's showing a 1920x1080 version of a 1280x1080 picture, and again, it looks much worse than the 1920x1080 equivelent (IMO).

Not only that but the effective perceived vertical resolution of 1080i tops out at about 756 for all raster-scanned images due to Kell factor alone (0.7X1080), including all images shot with a camera or telecined over from film, so a 768 V rez will not really display anything visibly different than a set with 1080 capability. And you have to be sitting less than 8 feet away from a 60" set for your eyes to resolve full 1920x1080 in the first place, assuming that resolution is even there in the first place, which it normally isn't.

Math again. I am at around 8 feet from my 60". And it does look much much better. Eyes trump math theory.


And none of that difference has anything at all to do with the amount of digital compression artifacts. That is an entirely different issue. If one set looks better than the other, you can rule out the amount of artifacts from the source content and you can all but rule out any reduced resolution. With different displays, there can be any number of other factors that could be creating a perceived difference, but I guess you can latch on to whatever superstitious theory you want to. You just won't have any proof or even acceptable theory to back it up.

It's hardly superstition. DirecTV is reducing the resolution. In doing so, they have to do something to the picture so it still looks okay - smoothing it, whatever. In doing so, they are creating a picture that looks much worse, at least on a 1080p TV, than the original.

It has nothing to do with compression artifacts, and I never said anything about artifacts.

It has to do with picture quality, and the quality of the source, original, OTA picture compared with the DirecTV recompressed, reduced rez, messed with picture.

And perhaps most importantly, FIOS isn't doing this at all - they are sending the full HD picture down, and they have substantially more HD (including locals). Cable also looks much better than DirecTV (although I can't compare on my TV, so it's not a fair comparison), and a better offering in my area.

DirecTV is messing with their high-end customers. We care about picture quality (not math).

[bdlucas]

I'm saying the picture looks better.
Can you say in what way the picture looks better? Sharper? Cleaner?

One thing that might have been missed in this discussion is that in addition to downresing the image, which in itself will soften the image a little, DirectTV may be further softening the image in order to allow for compression to a lower bitrate while minimizing the artifacts. That is, sharpness can be traded off against artifacts in a compressor.

As Ty has pointed out, the downresing that DirecTV is doing is probably not in itself enough to make a large difference in the quality of the image. Here's an illustration: the first image is the original, while in the second image I've simulated DirecTV's downresing (by downresing to 66% in the horizontal direction and then upresing to 150%). The difference is noticeable, but not enormous.

http://goldfishpond.net/images/1.jpg http://goldfishpond.net/images/2.jpg

Here's an illustration of the tradeoff of sharpness for artifacts at a given bitrate. Both of the following images have been compressed to 5K bytes. The first image is unprocessed before compression, while the second has been softened before compression (without changing the resolution). Result is a softer image but fewer artifacts. I wouldn't be surprised if DirecTV is doing something like this.

http://goldfishpond.net/images/3.jpg http://goldfishpond.net/images/4.jpg

In otherwords, I suspect TyroneShoes is right in that the downresing itself probably doesn't make a big difference in quality, and AbMagFab is right that DirecTV is degrading the quality of the picture in a way that becomes more noticeable on a higher-resolution screen.

[AbMagFab]

Can you say in what way the picture looks better? Sharper? Cleaner?

One thing that might have been missed in this discussion is that in addition to downresing the image, which in itself will soften the image a little, DirectTV may be further softening the image in order to allow for compression to a lower bitrate while minimizing the artifacts. That is, sharpness can be traded off against artifacts in a compressor.

As Ty has pointed out, the downresing that DirecTV is doing is probably not in itself enough to make a large difference in the quality of the image. Here's an illustration: the first image is the original, while in the second image I've simulated DirecTV's downresing (by downresing to 66% in the horizontal direction and then upresing to 150%). The difference is noticeable, but not enormous.

http://goldfishpond.net/images/1.jpg http://goldfishpond.net/images/2.jpg

Here's an illustration of the tradeoff of sharpness for artifacts at a given bitrate. Both of the following images have been compressed to 5K bytes. The first image is unprocessed before compression, while the second has been softened before compression (without changing the resolution). Result is a softer image but fewer artifacts. I wouldn't be surprised if DirecTV is doing something like this.

http://goldfishpond.net/images/3.jpg http://goldfishpond.net/images/4.jpg

In otherwords, I suspect TyroneShoes is right in that the downresing itself probably doesn't make a big difference in quality, and AbMagFab is right that DirecTV is degrading the quality of the picture in a way that becomes more noticeable on a higher-resolution screen.

Perfect.

The first set is very much like what I see when comparing OTA to DirecTV's version of the same thing. In fact, it's almost like the first picture = OTA, and the fourth picture is DirecTV's version. Yes, better than SD, but noticably worse (to me) than the same signal OTA.

I guess detail is the word I would use. There's a noticable degredation in detail on DirecTV's HD.

[newsposter]

All this talk really makes me glad I only get 2 Hd stations on the satellite and the rest OTA.

heck I'm even getting the very weak pbs station from philly now! (located actually in DE)

and now I see nbc 10 apparently has chosen uhf 34..yippee

http://www.fcc.gov/fcc-bin/tvq?list=0&facid=63153

[SpankyInChicago]

CRT's are analog, and so it's a very different picture. Generally speaking, the newer digital 1080i's, especially the SXRD/D-ILA's are considered better, perhaps much better than the CRT's.

Totally subjective statement.

Perhaps if you are taking a low-end, big-box RP-CRT for $1100 and comparing it to a $5000 SXRD.

I had the choice between a $13,000 Qualia 006 and a $3500 Mitsubishi WS-65815. Both were within my budget. I had narrowed it down to a choice between these two after months of research. I think the Qualia 006 looked great. I will admit I had a hard time deciding which looked better. But the Qualia was not "much better" than the CRT. For film, I felt it was worse than the Mits. For sports, I felt it was better. Overall, all things considered, I still think the RP-CRT Mits looked overall better than the "top of the line" Qualia 006. That is what I went with and I saved $9,500.

[f300v10]

Are they actually watchable? Two of my neighbors and another friend have all upgraded to the H20. According to all three of them the HD locals from DirecTv are all but unwatchable.

They have all had DirecTV out to replace the LNB, run new cabling, and repoint the new dish. In each case the picture still pixelates all the time.

They have been told it was their TV, it is a software problem DirecTV is working on, and that DirecTV has no idea why it does not work but they are trying to figure out why.

I think I have read posts from your friends on the Atlanta area yahoo HDTV group. I have had no such issues since my install Dec. 10th. My D* HD locals are pretty much identical to the OTA versions 98% of the time. When the weather is bad I have seen some dropouts, but the rest of the time the D* locals look very good. The one exception seems to be football on CBS or NBC. The turf has some visible compression artifacts on the D* version that are not visible on the OTA version. ABC and Fox don't have that problem.

[AbMagFab]

I had the choice between a $13,000 Qualia 006 and a $3500 Mitsubishi WS-65815. Both were within my budget. I had narrowed it down to a choice between these two after months of research. I think the Qualia 006 looked great. I will admit I had a hard time deciding which looked better. But the Qualia was not "much better" than the CRT. For film, I felt it was worse than the Mits. For sports, I felt it was better. Overall, all things considered, I still think the RP-CRT Mits looked overall better than the "top of the line" Qualia 006. That is what I went with and I saved $9,500.

Amazingly, 99% of people think the TV they bought is they best choice.

Even if it wasn't, and even if much better choices are available now.

[SpankyInChicago]

Amazingly, 99% of people think the TV they bought is they best choice.


Exactly. Because the "best" TV choice almost always depends on subjective observations. To say that one technology is "clearly" better than others with the state of TV technology today is to show ignorance of the subject. Of course, that may change in five years. But at this point, digital sets are not clearly better than CRT sets nor are CRT sets clearly better than digital sets.

But I do understand that some people need to justify to themselves the fact that they were marketed into believing one technology was vastly superior to another.

[newsposter]

Amazingly, 99% of people think the TV they bought is they best choice..

I'd add "at the price they wanted to pay for their current needs." I know darn well there are tons of better HD tvs out there but I wasn't ready to pay for them :)

[bdlucas]

Amazingly, 99% of people think the TV they bought is they best choice.
Only those who are in denial about their buyer's remorse.

[AbMagFab]

Exactly. Because the "best" TV choice almost always depends on subjective observations. To say that one technology is "clearly" better than others with the state of TV technology today is to show ignorance of the subject. Of course, that may change in five years. But at this point, digital sets are not clearly better than CRT sets nor are CRT sets clearly better than digital sets.

But I do understand that some people need to justify to themselves the fact that they were marketed into believing one technology was vastly superior to another.

Except my TV is better than your TV.

[Budget_HT]

Okay children, let's be civil now.

Everyone is entitled to their own opinion.

Life would be boring if everyone agreed on everything.

I have one of each type of TV (RPTV CRT and direct view LCD), and I see strengths and weaknesses in each. Oh, and I set up a DLP RPTV for a close relative, and even it has different attributes, some better and some worse.

There is no single best here. Rankings are based on one's personal requirements, priorities and expectations.

[NoThru22]

I still need to catch up with a lot that was said on page 3, but two things stood out to me so far:
Imagine an input stream X. If you were to compress X using MPEG2 at Y bit rate and compare it to X compressed using MPEG4 at Y bit rate, the resultant MPEG4 stream would look superior to the resultant MPEG2 stream. In other words, all things being equal (input source, output bit rate, encoder quality, etc.) MPEG4 results in superior picture quality than MPEG2.
This is all going off the assumption that the mpeg2 and mpeg4 streams will be converted from the same source. I would assume that the mpeg4 stream will actually be derived from a decoded mpeg2 stream (I would more than assume actually, I'd put money on it) so by it's very nature the mpeg4 stream will always be inferior to the mpeg2 stream, even if only by a little (which, I will guess it will be more than a little and actually on the level of the current downrezzing.) This will not be like Blu-ray and HD-DVDs that will have direct mpeg4 transfers from the original source that will be gorgeous (if done properly.)
Amazingly, 99% of people think the TV they bought is they best choice.

Even if it wasn't, and even if much better choices are available now.
I will refer you to my old quote: Ijustboughtcrapitis- the disease that makes a person delude themself into believing the crap they just bought is the best because they spent too much on it.

[newsposter]

another posting I've just run across and since a direct answer to the thread title, here it is:

H20 Hard Reboot
I upgraded last month to the H20 Mpeg4 set top box. I hooked up my OTA antenna and all the OTA local channels are great except for Fox , (2-1) in the local Detroit area. When I tune to the Fox OTA channel the H20 immediately goes into a hardware reboot. I am using the HDMI output to a Sony Ruby projector.

Anyone have this problem and a solution?

I use the OTA antenna because the quality of the local OTA broadcasts are substantially better than what D provides. Also was not informed at time of upgrade there was a 2 year commitment. And the hoops they make you go through just to apply for the $200 rebate combined with the fact that they rarely send it, has me rethinking why I am even doing business with these people. Thanks for any help you can provide.

[AbMagFab]

Okay children, let's be civil now.

Everyone is entitled to their own opinion.

Life would be boring if everyone agreed on everything.

I have one of each type of TV (RPTV CRT and direct view LCD), and I see strengths and weaknesses in each. Oh, and I set up a DLP RPTV for a close relative, and even it has different attributes, some better and some worse.

There is no single best here. Rankings are based on one's personal requirements, priorities and expectations.

But you don't have a 1080p digital TV, so you can't compare.

Your TV's are old and unfashionable.

[AbMagFab]

I upgraded last month to the H20 Mpeg4 set top box. I hooked up my OTA antenna and all the OTA local channels are great except for Fox , (2-1) in the local Detroit area. When I tune to the Fox OTA channel the H20 immediately goes into a hardware reboot. I am using the HDMI output to a Sony Ruby projector.

Sounds like the box is making a qualitative judgement on your programming choices. Like the FCC, the H20 is telling you what you can, and can't watch.

I use the OTA antenna because the quality of the local OTA broadcasts are substantially better than what D provides.

Sounds like we finally have a 1-1 comparitive answer to the original poster. OTA is far greater quality than DirecTV MPEG-4. At least in Detroit.

No surprise here. We've been saying it for 3+ pages...

[dswallow]

Your TV's are old and unfashionable.
I would advise against saying their TV's are unfashionable. ;)

I was refrigerator shopping a few weeks ago and came across a modern version of that old-style Frigidaire look complete with the locking pull handle and rounded corners. $3999, too. A price premium for something that looked like it was from the 50's.

It wasn't this one, but a simple search came up with it:

http://www.appliance.com/np_images/BC.jpg

It'll be amusing when someone creates a round HD plasma just to get that old fashioned round CRT look. :)

[NoThru22]

CRT's are analog, and so it's a very different picture. Generally speaking, the newer digital 1080i's, especially the SXRD/D-ILA's are considered better, perhaps much better than the CRT's.

The CRT's weren't really 1080i, in that they weren't displaying every pixel. The digital 1080i's display each and every pixel. But to some, this is an album/CD debate in terms of the overall experience.
This isn't the place for this discussion, but has it been proven that 1080p displays support 1:1 pixel mapping with deinterlaced 1080i signals? Over HDMI only then?

[SpankyInChicago]

This is all going off the assumption that the mpeg2 and mpeg4 streams will be converted from the same source. I would assume that the mpeg4 stream will actually be derived from a decoded mpeg2 stream (I would more than assume actually, I'd put money on it) so by it's very nature the mpeg4 stream will always be inferior to the mpeg2 stream, even if only by a little (which, I will guess it will be more than a little and actually on the level of the current downrezzing.)

Correct. I said pretty much the same thing here:

http://www.tivocommunity.com/tivo-vb/showthread.php?p=3716906&&#post3716906

Of course such a suggestion leads to the discussion of "technically" superior vs. visually "superior." It would be possible for the recompressed stream to be technically ingerior to the original stream but not be visually inferior.

Like you said, it all depends on just how much they are recompressing.

[AbMagFab]

People who have the H20 and OTA have been posting around in threads saying how much worse the DirecTV HD is compared to OTA.

I think this question is clearly answered, and we can drop the theory.

DirecTV HD currently sucks (compared to OTA), and the MPEG-4 HD is just as bad, if not worse.

[bdlucas]

People who have the H20 and OTA have been posting around in threads saying how much worse the DirecTV HD is compared to OTA.

I think this question is clearly answered, and we can drop the theory.

DirecTV HD currently sucks (compared to OTA), and the MPEG-4 HD is just as bad, if not worse.
I've seen mixed postings on the topic of MPEG4 vs OTA picture quality, a couple right here in this thread reporting little visible difference. I wouldn't be surprised if it varies by market.

[f300v10]

I've seen mixed postings on the topic of MPEG4 vs OTA picture quality, a couple right here in this thread reporting little visible difference. I wouldn't be surprised if it varies by market.

Exactly. When the Atlanta market first went on line, NBC was very poor via D*, the other 3 channels have always been good. After about 2 weeks NBC was much improved. The D* locals are good enough 98% of the time that I can't tell which version I am watching unless I hit the info button.

The same may not be true for the other markets. But it does show that with the hardware D* is using, the PQ of the MPEG4 locals can be very good. And I am not the only one saying this. The intial reports out of the Detroit market all said the D* version was a match for OTA. Atlanta is as well. And D* is still giving you the option to watch the OTA version if you want to.

[slapshot]

I'm upgrading(?) my system next week to get the local HD channels here in Chicago area,along with a new H20,got it all for free.
Curious if anyone in this area can tell me how the locals look compared to their other HD channels,seeing as other cities don't seem to compare to OTA?

I'm also going to ask them to mount a rooftop antenna anyway so I can keep my HDTivo for as long as possible,or get another one if they discount them heavily like they are doing with the SD Tivo's.

With the offer I got I have to give them my Hughes HTL in return for the free H20. When they eventually come out with their own brand of HD DVR later this year,I'm curious as to what
they'll charge for it,(or lease only?),becuase I'm not giving up my Tivo.

[lromoda]

I have OTA, MPEG2, and MPEG4 available for viewing on the same set with an H20. Granted, it's my 42" Mits 1080i CRT rear projection. My 60" Sony 720p LCD rear proj is waiting for the HR. Wife and I flipped through all 3 for a few minutes watching Letterman. Our subjective opinion is that if you had to pick a loser among the 3, it would be the MPEG4. Can't tell you why with any kind of authority. However, the most annoying thing was that NBC's MPEG4 audio sync is so far off, it's unwatchable. The others were fine on sync, lower in volume than MPEG2 and OTA.

[newsposter]

I'm upgrading(?) my system next week to get the local HD channels here in Chicago area,along with a new H20,got it all for free.
Curious if anyone in this area can tell me how the locals look compared to their other HD channels,seeing as other cities don't seem to compare to OTA?

I'm also going to ask them to mount a rooftop antenna anyway so I can keep my HDTivo for as long as possible,or get another one if they discount them heavily like they are doing with the SD Tivo's.
.

You may want to search on here what antenna is best for your area. Also the avsforum will have your local area listed.

also in case you didn't know, only the big 4 networks are on mpeg4 in HD.

[newsposter]

here's a chart of some bitrates for OTA and DTV

http://www.widemovies.com/dfwbitrate.html

[MeStinkBAD]

Boy I've sure seen some dumb things said in this thread. Stop complaining about MPEG4. MPEG4 is not the problem, MPEG2 is. MPEG2 is far too much of a bandwitdh hog for HD broadcasts. Look there are like 400 channels on DTV maybe ten of them are in HD. Wanna know why just ten? There probably isn't room for anymore. So MPEG2 has gotta die and MPEG4 x264 needs to take it's place. Go ahead and say that an MPEG4 stream won't be just as good as MPEG2. That's the same as saying as MPEG2 will never be as good as a raw unpressed feed. If you wanted a direct feed, that would be the only station you get.

MPEG4 is a very high quality lossy compression scheme. The problems people are experiance now with it are not because of MPEG4 but because it's just being started to be put in use for broadcasting. You are always gonna have one or two bugs at the start.

I live in a small town, about 60 miles from where they broadcast OTA signals. I doubt it's possible me to get a decent signal at the moment. Hopefully that will change by the end of the year, when analog is replaced by digital. Oh and DTV won't be offering MPEG4 broadcasts of local stations till April. And I still can't receive East/West coast broadcasts yet. But I'm not bothered by DTV being inferiour to OTA either. The only time anythiing is broadcast in HD is during prime time. Besides it's MPEG2 and it takes up too much space on the drive.

I imagine local stations will stop broadcasting MPEG2 signals as well. MPEG4 is quite superior. Personally I think you'd be a fool to choose MPEG2 over MPEG4. Beleive me, MPEG4 broadcast will probably look just as good as OTA MPEG2. Well you wouldn't know anyhow since you couldn't compare anymore.

AbMagFab, all I have to ask is why did you buy a set that upscales everything to 1080p? 1080p may never even become an offically broadasted signal. Please stop complaining that things don't look good with it and use a different TV.

[AbMagFab]

Boy I've sure seen some dumb things said in this thread. Stop complaining about MPEG4. MPEG4 is not the problem, MPEG2 is. MPEG2 is far too much of a bandwitdh hog for HD broadcasts. Look there are like 400 channels on DTV maybe ten of them are in HD. Wanna know why just ten? There probably isn't room for anymore. So MPEG2 has gotta die and MPEG4 x264 needs to take it's place. Go ahead and say that an MPEG4 stream won't be just as good as MPEG2. That's the same as saying as MPEG2 will never be as good as a raw unpressed feed. If you wanted a direct feed, that would be the only station you get.

MPEG4 is a very high quality lossy compression scheme. The problems people are experiance now with it are not because of MPEG4 but because it's just being started to be put in use for broadcasting. You are always gonna have one or two bugs at the start.

I live in a small town, about 60 miles from where they broadcast OTA signals. I doubt it's possible me to get a decent signal at the moment. Hopefully that will change by the end of the year, when analog is replaced by digital. Oh and DTV won't be offering MPEG4 broadcasts of local stations till April. And I still can't receive East/West coast broadcasts yet. But I'm not bothered by DTV being inferiour to OTA either. The only time anythiing is broadcast in HD is during prime time. Besides it's MPEG2 and it takes up too much space on the drive.

I imagine local stations will stop broadcasting MPEG2 signals as well. MPEG4 is quite superior. Personally I think you'd be a fool to choose MPEG2 over MPEG4. Beleive me, MPEG4 broadcast will probably look just as good as OTA MPEG2. Well you wouldn't know anyhow since you couldn't compare anymore.

AbMagFab, all I have to ask is why did you buy a set that upscales everything to 1080p? 1080p may never even become an offically broadasted signal. Please stop complaining that things don't look good with it and use a different TV.

I haven't seen so much uneducated whining in a while. Nice!

Let me try to help you out:

1) 1080i (the bulk of HD out there) is only fully resolved on a 1080p digital set. Digital sets only do "p", even with an "i" source. Check out some HDTV primers to get yourself a little more educated on this topic.

2) "Bit for bit", MPEG-4 is better than MPEG-2. That is, in the same bandwidth, MPEG-4 will produce a better picture. Problem is, DirecTV is using both MPEG-4 and significantly shrinking the bandwidth. At best, MPEG-4 produces an equal picture to MPEG-2 in about half the space (and that's a huge leap). DirecTV appears to be using less than half the space for each MPEG-4 channel, resulting in a worse picture.

3) MPEG-4 is a huge issue when recompressing an MPEG-2 stream. Lossy on top of lossy equals worse picture, and DirecTV appears to be recompressing the MPEG-2 feed, not the source uncompressed HD feed. But it's irrelevent since OTA is MPEG-2 - that's the baseline we're all working with, and it isn't going to change in our lifetime (except yours if you're about 10, like you sound).

4) No one is complaining about the "theory" of MPEG-4, but everyone is complaining that DirecTV is constantly sacrificing picture quality, and the effect of DirecTV using MPEG-4 is to reduce picture quality. And it's already proven in some markets where people are viewing OTA side-by-side with DirecTV's recompressed MPEG-4 version.

5) DirecTV is offering MPEG-4 locals today in many markets, including my own.

Pay attention and you might learn something.

[SpankyInChicago]

Boy I've sure seen some dumb things said in this thread. Stop complaining about MPEG4. MPEG4 is not the problem, MPEG2 is. MPEG2 is far too much of a bandwitdh hog for HD broadcasts. Look there are like 400 channels on DTV maybe ten of them are in HD. Wanna know why just ten? There probably isn't room for anymore. So MPEG2 has gotta die and MPEG4 x264 needs to take it's place. Go ahead and say that an MPEG4 stream won't be just as good as MPEG2. That's the same as saying as MPEG2 will never be as good as a raw unpressed feed. If you wanted a direct feed, that would be the only station you get.

MPEG4 is a very high quality lossy compression scheme. The problems people are experiance now with it are not because of MPEG4 but because it's just being started to be put in use for broadcasting. You are always gonna have one or two bugs at the start.

I live in a small town, about 60 miles from where they broadcast OTA signals. I doubt it's possible me to get a decent signal at the moment. Hopefully that will change by the end of the year, when analog is replaced by digital. Oh and DTV won't be offering MPEG4 broadcasts of local stations till April. And I still can't receive East/West coast broadcasts yet. But I'm not bothered by DTV being inferiour to OTA either. The only time anythiing is broadcast in HD is during prime time. Besides it's MPEG2 and it takes up too much space on the drive.

I imagine local stations will stop broadcasting MPEG2 signals as well. MPEG4 is quite superior. Personally I think you'd be a fool to choose MPEG2 over MPEG4. Beleive me, MPEG4 broadcast will probably look just as good as OTA MPEG2. Well you wouldn't know anyhow since you couldn't compare anymore.

AbMagFab, all I have to ask is why did you buy a set that upscales everything to 1080p? 1080p may never even become an offically broadasted signal. Please stop complaining that things don't look good with it and use a different TV.

1. Local stations will not stop broadcasting in MPEG2 anytime in the next 10 or 20 years. How long did it take to get ATSC implemented? ATSC has no provision that I am aware of to allow broadcasting in MPEG4. How long do you think it will take to get ATSC upgraded to allow for broadcasting in MPEG4? Exactly. A very long time.

2. MPEG4 is not "better" or "worse" than MPEG2. It is just more efficient. If 100 bits go into MPEG2 and 50 bits come out at some X bitrate, then given the same X bitrate a 100 bits into MPEG4 will come out in 25 bits with the approximate same quality as the MPEG2 stream. If however you lower X bitrate to X/2 and then feed 100 bits into MPEG4 will come out in 12 bits, but the quality will be have of 100 bits in MPEG2 at X bitrate. That is the concern that people are raising: will DirecTV use the increased efficiency of MPEG4 to increase video quality, decrease video quality, or keep video quality the same? MPEG4 does not mean that quality will improve as you suggest.

[kevlarian]

Ok guys, I have been reading, and reading, and reading...

The origional question... is OTA better than MPG4?

Lets start from the begining. No, OTA is not better than MPG4. MPG4 is not better than OTA. They are different, and at the end of the day accomplish the same thing.

OTA uses MPEG-2 to transmit data... MPEG-2 is an older compression format than MPEG-4. As with MOST "newer" technologies MPEG-4 offers some advantages over MPEG-2.

In theory, the same image quality SHOULD be realized between MPEG-2 and MPEG-4. But MPEG-4 requires about 1/3 less less data to reproduce the same image. So (in theory) if a MPEG-2 image requires 100 bits of data, the same MPEG-4 image would require only 66 bits of data. The reason why SAT providres choose MPEG-4 over MPEG-2 is obvious. They can offer more channels with fewer sattelites that would be required for all MPEG-2 signals.

...NOW...

There are a number of factors that go into the ENCODING (or the creation) of the broadcast stream. The most important of which is the image (data) source. If you are creating an MPEG-2 and MPEG-4 image from the same source, you (in theory) should have the SAME image. If, however, you create an MPEG-4 image from an already compressed MPEG-2 image, the MPEG-4 image would not look as good as the MPEG-2 image. The same goes the other way... If you create an MPEG-2 image from an MPEG-4 image, your MPEG-2 image would not look as good as your MPEG-4 image.

So if D* or DTV is generating an MPEG-4 image from an OTA MPEG-2 image... then there would be a slight loss in quality. If, however, they are streaming an MPEG-4 image based on a non-compressed digital source (direct from the station), then the MPEG-4 image would broadcast with NO image difference then the OTA MPEG-2.

We can go on and on on this subject (including the arguments over 720p vs. 1080i. vs 1080p), but at the end of the day... it all comes down to choice and preference.

...FINALLY...

I have a 56" 720p Samsung DLP TV. I can tell you that I have seen BOTH OTA and D* locals, and ON MY TV, I can see no OBVIOUS differences between the two. Considering that SOME stations are NATIVE 1080i broadcast, and others are 720p, and as such, each broadcast has different "artifacts" associated with the different broadcast standards, the broadcast from D* and DTV are ALL standardized to 1080i.

SO many factors are involved with this process... the Data Source, the Broadcast method, the compression standard, the compression AMOUNT, the decoder quality (SAT receiver), and the display (your HD TV capabilities and/resolution), that there is NO right or wrong answer.

Suck it up... do what you want to do based on your knowledge, and your budget.

[AbMagFab]

Ok guys, I have been reading, and reading, and reading...

The origional question... is OTA better than MPG4?

Lets start from the begining. No, OTA is not better than MPG4. MPG4 is not better than OTA. They are different, and at the end of the day accomplish the same thing.

OTA uses MPEG-2 to transmit data... MPEG-2 is an older compression format than MPEG-4. As with MOST "newer" technologies MPEG-4 offers some advantages over MPEG-2.

In theory, the same image quality SHOULD be realized between MPEG-2 and MPEG-4. But MPEG-4 requires about 1/3 less less data to reproduce the same image. So (in theory) if a MPEG-2 image requires 100 bits of data, the same MPEG-4 image would require only 66 bits of data. The reason why SAT providres choose MPEG-4 over MPEG-2 is obvious. They can offer more channels with fewer sattelites that would be required for all MPEG-2 signals.

...NOW...

There are a number of factors that go into the ENCODING (or the creation) of the broadcast stream. The most important of which is the image (data) source. If you are creating an MPEG-2 and MPEG-4 image from the same source, you (in theory) should have the SAME image. If, however, you create an MPEG-4 image from an already compressed MPEG-2 image, the MPEG-4 image would not look as good as the MPEG-2 image. The same goes the other way... If you create an MPEG-2 image from an MPEG-4 image, your MPEG-2 image would not look as good as your MPEG-4 image.

So if D* or DTV is generating an MPEG-4 image from an OTA MPEG-2 image... then there would be a slight loss in quality. If, however, they are streaming an MPEG-4 image based on a non-compressed digital source (direct from the station), then the MPEG-4 image would broadcast with NO image difference then the OTA MPEG-2.

We can go on and on on this subject (including the arguments over 720p vs. 1080i. vs 1080p), but at the end of the day... it all comes down to choice and preference.

...FINALLY...

I have a 56" 720p Samsung DLP TV. I can tell you that I have seen BOTH OTA and D* locals, and ON MY TV, I can see no OBVIOUS differences between the two. Considering that SOME stations are NATIVE 1080i broadcast, and others are 720p, and as such, each broadcast has different "artifacts" associated with the different broadcast standards, the broadcast from D* and DTV are ALL standardized to 1080i.

SO many factors are involved with this process... the Data Source, the Broadcast method, the compression standard, the compression AMOUNT, the decoder quality (SAT receiver), and the display (your HD TV capabilities and/resolution), that there is NO right or wrong answer.

Suck it up... do what you want to do based on your knowledge, and your budget.
Wow... How can you even say all this nonsense?

#1 - The uncompressed feed is the best, obviously.

#2 - MPEG-2 os older, but that doesn't mean MPEG-4 is better visually. MPEG-4 really is just about better compression, so using the same bandwidth, MPEG-4 should do a better job and squeezing in the video. But if you let MPEG-2 do it's thing, it can actually look better than MPEG-4 since it's compressing less. Wildly inaccurate statements above.

#3 - DirecTV is apparently getting the MPEG-2 feed from stations (last I heard, via Level3). They will then recompress using MPEG-4. This will, by definition, produce a lower quality picture. Will you care? Will you be able to tell on your older TV? That's up to you. Reports of the current H20 users certainly point to some big problems with the MPEG-4 locals, and those may or may not get fixed.

#4 - To make any judgement about these formats, and resolution degredation, you really need to use a newer TV. 720p sets simply can't resolve the full 1080i pict