OTA HD vs Mpeg4 HD

Discussion in 'DirecTV TiVo Powered PVRs & Receivers' started by buzzmc1, Dec 22, 2005.

  1. Feb 1, 2006 #101 of 118
    SpankyInChicago

    SpankyInChicago New Member

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    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.
     
  2. Feb 1, 2006 #102 of 118
    AbMagFab

    AbMagFab What happened, TiVo?

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    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.
     
  3. Feb 1, 2006 #103 of 118
    bdlucas

    bdlucas Right side up again.

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    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.
     
  4. Feb 2, 2006 #104 of 118
    f300v10

    f300v10 New Member

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    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.
     
  5. Feb 2, 2006 #105 of 118
    slapshot

    slapshot New Member

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    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.
     
  6. Feb 3, 2006 #106 of 118
    lromoda

    lromoda New Member

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    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.
     
  7. Feb 3, 2006 #107 of 118
    newsposter

    newsposter Poster of News

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    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.
     
  8. Feb 6, 2006 #108 of 118
    newsposter

    newsposter Poster of News

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  9. Feb 7, 2006 #109 of 118
    MeStinkBAD

    MeStinkBAD Member

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    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.
     
  10. Feb 7, 2006 #110 of 118
    AbMagFab

    AbMagFab What happened, TiVo?

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    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.
     
  11. Feb 7, 2006 #111 of 118
    SpankyInChicago

    SpankyInChicago New Member

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    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.
     
  12. Mar 3, 2006 #112 of 118
    kevlarian

    kevlarian New Member

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    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.
     
  13. Mar 3, 2006 #113 of 118
    AbMagFab

    AbMagFab What happened, TiVo?

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    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 picture, and as such many of the things DirecTV does to their retransmitted signal won't be apparent to you.

    I appreciate your energy on the matter, but you just don't have the data or HD TV to make such overarching conclusions.
     
  14. Mar 3, 2006 #114 of 118
    peterbilt

    peterbilt New Member

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    D/FW
    I must say that this is one of the longest, most topically irrelevant threads I have ever muddled through. In response to the quesion, "Which looks better?" we get all this discussion of digital display technology and the future of broadcasting. WTF.

    Maybe he should have structered his thread as a poll so that people would be obligated to answer the question asked. I know I'm ranting/venting, but good greif. The information in this thread is not without merit, but I think the original poster wanted practical results, not debate on the merits of MPEG2 vs MPEG4, or compression algorithms, or vertical refresh rates. The bottom line is how does it look?

    For what all that tech-talk is worth, should people include their eyelgass perscription information along with the lines of resolutions of their displays?
     
  15. Mar 3, 2006 #115 of 118
    MeCurious

    MeCurious New Member

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    I have DirectTV and an OTA antenna. Just from a visual point of view. HDNET has a very smooth picture. Discovery HD has a detailed picture on most shows but just ok on some others. The program Sunrise Earth on Discovery can sometimes look demo quality. TNTHD looks bad most of the time with it's stretched picture. But if it is true HD, it looks reasonably detailed. But all of them can not touch CBS OTA. The picture on that netwok is so detailed, I can tell when the actors have too much makeup on. On CSI-Miami, there are so many lines shown on the actors faces, you can tell who had a bad night the night before. The quality on the CSI shows on CBS is outstanding. I cannot say how good the picture for these shows are on CBS Satellite west coast feed because I can't get them. But I can say the picture OTA is more detailed than HDNET and I love the picture on HDNET. NBC has a very detailed picture most of the time. Crossing Jordan and Las vegas have very intense colors on OTA. ABC's picture is not as detailed to my eyes. It's a pretty good picture. But Modany night football didn't give me the shocked good look of a picture as football looks on CBS. I don't watch many shows on Fox so I can't give a valid opinion. Smallville on the WB is excellent OTA. The picture looks almost movie like.

    So the bottom line to me is the OTA picture is very detailed to watch but the satelite picture can be quite mesmerrizing if it has a good signal. But the quality varies based on this signal.
     
  16. Mar 6, 2006 #116 of 118
    jvrobert

    jvrobert New Member

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    What nonsense?

    I love when people are not only wrong, but openly hostile about being wrong. The original poster said nothing incorrect, everything he said is correct. You seem to be arguing just for the sake of arguing.

    About #2, MPEG-4 is better visually when "better" means "image quality per bitrate". At the same bitrate, a _good_ MPEG-4 encoder will at worst match and generally best an MPEG-2 encoder. I'm not sure what this "let MPEG-2 do it's thing" crap is supposed to mean, a proper MPEG-4 encode at the same bitrate as any MPEG-2 encode will look the same or better.
     
  17. Mar 6, 2006 #117 of 118
    SpankyInChicago

    SpankyInChicago New Member

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    AbMagFag got marketed into the 1080p hype so he needs to justify the amount he overpayed on his wobulator by attacking people who don't have 1080p sets.

    [AbMagFag]
    If you don't have a 1080p set, you can't tell the difference between good HD and bad HD.
    [/AbMagFag]

    :rolleyes:
     
  18. Mar 6, 2006 #118 of 118
    TyroneShoes

    TyroneShoes HD evangelist

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    I think that might be the least of her problems.

    But MPEG-2 is visually better only if it is exactly that...visually better. That means an objective evaluation at the end of the line, which can be either better or worse, depending upon how well the technology is applied. In the case of MPEG-2 vs. MPEG-4, there is just no telling, because the parameters are not defined. I have MPEG-4 on my Mac that blows away the "economy" setting of a 14-hr MPEG-2 Tivo, but I have seen MPEG-2 DVDs that blow that away, too.

    Without defining the parameters, that's like saying potatoes are better than brussel sprouts. A raw rotten unwashed potato might not be as good as well-prepared brussel sprouts (but I know some siblings who would still rather eat the potato :D ).

    In DTV's case for HD, there is only one thing we know for sure, and that is that MPEG-2 converted to MPEG-4, no matter how artfully done and no matter how many bits are allocated to it, will be measurably inferior to original MPEG-2 as received OTA. That is a fact of the laws of physics and the unavoidable concatenation of chaining disimilar algorithms. But, it still might be superior to the MPEG-2 HD channels they now provide, again depending upon how well they do it.

    No vendor will have access to HD from local stations before they format it to SMPTE310, and ATSC PQ never degrades, so no vendor can provide better PQ in that area than OTA. Cable can usually match it, DTV can almost match it (hopefully they will) but no vendor can provide any improvement to it, whether they use MPEG-2, MPEG-4, or even JPEG2000 processing. And I seriously doubt they will improve their non-local channels to be significantly better than the other channels they carry.
     

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