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MPEG-4 HD Quality

Discussion in 'DIRECTV HD DVR/Receiver Discussion' started by jeffnebraska, Nov 7, 2006.

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  1. tstarn

    tstarn Banned User

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    Yeah, that CD quality sound line is a complete joke. Anyone with a serious home stereo setup and D* via DD 5.1 knows it (or even in the XM/Sirius standalone receivers). It's an amazing piece of puffery. Unfortunately, OTA where I live in Philly isn't going to happen. Just too much interference and I don't want to put another antenna on the roof, so I just ignore it. I only wish it was an option.
     
  2. ChromaTick

    ChromaTick AllStar

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    Sep 2, 2006
    I can't get OTA, so I have nothing to compare to.

    I get CBS and NBC through MPEG4 and I find the quality to be up and down. Sometimes it looks absolutely phenomenal, and other times it doesn't look much better than SD. For instance, I'm watching Friday Night Lights (NBC) right now and it's got terrible macro blocking, yet Monday night Heroes (NBC) looked absolutely gorgeous.
     
  3. jeffnebraska

    jeffnebraska Mentor

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    So, it seems like there's no clear consensus that the MPEG4 HD picture is better than the mediocre MPEG2 HD picture I'm getting with my HDTivo. It also seems that most who get OTA HD still feel D* MPEG4 HD is not as good. That's a real shame.

    Boy do I wish I lived somewhere where I could get Verizon Fios. Maybe I should be giving Comcast a try.
     
  4. eengert

    eengert Legend

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    There will likely be no difference in PQ via OTA on HR20 vs. HR10. The difference in the tuners is their sensitivity, meaning their ability to pull in a stronger signal. But that has nothing to do with PQ.
     
  5. LameLefty

    LameLefty I used to be a rocket scientist

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    That's a classic case of a bit-starved data stream and/or an improperly-optimized compression of the source material - the times when compression is lower (and more bits allocated to the channel), you'll have much better quality. Alternately, for the same number of bits, the better-optimized recording should give a better picture. Not sure how D* can address the bandwidth part of the equation without more sats and more individual spotbeams for locals at those locations. Compression techniques will continue to be tweaked, as will encoding hardware I'm sure. I've seen noticeable overall improvements in the worst of the Nashville locals (CBS) in the last three weeks, though still not "perfect." Hopefully the trend will continue.
     
  6. ChromaTick

    ChromaTick AllStar

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    Totally agree. I just find it amusing that it literally can change from show to show on the same channel. FNL was horrible last night, but The Unit came on right after and looked fantastic. :)
     
  7. Jeremy W

    Jeremy W Hall Of Fame

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    Barring the encoder problems that are plaguing some markets, the MPEG4 channel will beat the MPEG2 channel every single time. There is no need for a "consensus" on this, it's just a technical fact.
     
  8. LameLefty

    LameLefty I used to be a rocket scientist

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    I think that would only be true if all other factors were equal, including bit-rate for each stream. E.g., MPEG4 is a more-efficient codec and will result in a better picture for the same bandwidth. However, the whole drive to MPEG4 is to reduce bit-rate per channel to allow more channels to be carried per transponder. I think the best we can hope for is that that the MPEG4 HD channels eventually match the current quality of MPEG2 HD channels.
     
  9. btmoore

    btmoore Hall Of Fame

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    Since the source is MPEG2 and that is being converted to MPEG4 and both MEPG4 and MPEG2 are both lossy compression algorithms, how exactly will the MPEG4 be better quality at best it could be close to the same but not better.

    If the original source was original transcoded into MEPG4 it could be better than MPEG2.

    If the currently transmitted MPEG2 is bitstarved and they are using a less aggressive compressed mpeg2 to transfrom to mpeg4 and they don't bitstarve the mpeg4 stream it might be better but it is not a fact that it will, there are too many variables to make that a statement of fact. You best source for local video will be OTA, assuming no sub channels and the mpeg is not mucked with too much at the local station you will get a full mpeg2 stream.

    But you are right about it being a technical fact, it is just your facts are wrong.
     
  10. Jeremy W

    Jeremy W Hall Of Fame

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    Do you have MPEG4 channels?
     
  11. Jeremy W

    Jeremy W Hall Of Fame

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    Right now, the fact is that they aren't bitstarving the MPEG4 channels as badly as they are the MPEG2 channels. So right now, the fact is that the MPEG4 channels look better than the MPEG2 channels. I never said it would always be this way, or that the fact that they are using MPEG4 just meant that the quality would be better. And I'm not going to qualify everything I say with "right now" either. Tomorrow, DirecTV could decide that each MPEG4 channel is going to get 2mbps, and turn them into a horrible mess. That much is obvious, so unless I say otherwise, I'm talking about the way things are today.
     
  12. LameLefty

    LameLefty I used to be a rocket scientist

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    Yes, the "Big 4" Nashville locals are all MPEG4 HD. CW, PBS and two or three independents are MPEG2 SD.
     
  13. HaiChinGow

    HaiChinGow AllStar

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    Oct 4, 2006

    Not quite a technical fact. MPEG4 codecs can produce superior results at LOWER bit rates, but as bit rates increase, their performance edge seriously diminishes and can result in lower quality.
     
  14. Jeremy W

    Jeremy W Hall Of Fame

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    See my previous post.
     
  15. btmoore

    btmoore Hall Of Fame

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    Based on my observations, they are bitstarving the MPEG4 at times and it appears to be variable in how they are doing this, it is not a "fact" that they are better just at times it may appear better and there are times whey my west coast nationals look better, but regardless OTA will likely be the best quality source because it is closest to the original source.
     
  16. Jeremy W

    Jeremy W Hall Of Fame

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    And do your MPEG4 locals really look worse than the MPEG2 nationals?
     
  17. Jeremy W

    Jeremy W Hall Of Fame

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    Considering the fact that DirecTV (in most cases) simply grabs the signal OTA, it will always be the best quality because it is the original source.
     
  18. btmoore

    btmoore Hall Of Fame

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    I am confused, are you agreeing that OTA MPEG2 is going to be the best quality, or are you saying that the D* mpeg4 converted from the mpeg2 OTA is the best source? BTW the original content source is the network stream that is fed to the broadcaster, the local provider can still screw up things when they add their local commercials and encode for mpeg2 & ATSC transmission. I am not sure if D* is relying on OTA for picking up the locals, I thought they were running data circuits to the locals to pick up the feed, both would work but I don't know the facts here.

    I am missing your point.
     
  19. Dusty

    Dusty Icon

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    I actually think you can see the consensus here. Most said MPEG4 local is not as good as OTA. There are no MEPG4 national channels for you to compare against the MPEG2 signals you are getting through HR10. It's too quick for you to draw the conclusion. They are not the same comparison.

    I will never expect MPEG4 local to be as good as OTA, but I personally am not bothered by the slight degradation. I live 3 miles away from TV towers, so I get excellent OTA signals. I have no problem living with the slight difference. In turns, I get the benefit of recording more shows because of the smaller footprint of MPEG4 decoding. For example, for me to record all 5 NFL games with padding on Sunday will pretty much take away most of my disk space. Throwing in a golf games, and Dexter, I actually have to scramblefor the disk space. With MPEG4, my disk looks a lot more spacious.

    As for the MEPG2 signal you are getting on HR10 (HD-Tivo), I think it has to do with source and the HD lite encoding. If they start transmitting in MPEG4 with original 1080i resolution, I think it won't be too bad.

    Comcast ranked number 2 on my personal don't do business with list. I will consider FIOS when it becomes available.
     
  20. btmoore

    btmoore Hall Of Fame

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    My big hope is we will get premium channels in a rich MPEG4 stream vs the bitstarved mpeg2/HD Light we are getting now. This would be a big improvement.
     
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