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DirecTV National HD Listing/Maps Discussion Thread (Technical - Not Anticipation)

Discussion in 'DIRECTV Programming' started by Sixto, May 29, 2012.

  1. Jul 5, 2012 #281 of 653
    P Smith

    P Smith Mr. FixAnything

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    Difference (seen that method in some DTV and dish DVRs) is in additional scrambling (to prevent copying from a drive).

    All other cases - DVR writing same stream (per one channel) what is coming from satellite.
    During play the file (recordings) pass same stages/routines/functions as sat stream.

    [I'm puzzled to see such speculations ... without any real supporting facts]
     
  2. Jul 5, 2012 #282 of 653
    veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    "I think" comparing playback bit-rates between the two is valid.
    As to DirecTV2PC, it's clear you haven't used it to monitor, because it's anything but "constant", with wide swings from 0 to 16+ Mb/s.
    "Anyway" what either service does on their feed, isn't something a user can monitor that well and "the end results" have shown U-Who to be using only 66% of what DirecTV is, for the exact same program at the exact same time.
     
  3. Jul 5, 2012 #283 of 653
    georule

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    I believe OTA does that kind of thing as well for sub-channels, with the main channel priortized to take the bw from the subs whenever it needs it. . . at least I know of one NBC station in a top 15 market that does it that way, and have no reason to suspect they're unique.

    I've always wondered how much lag there is in reacting to that, or if there's no lag but there is at least (what you're describing) one of the channels being bit-robbed for a few frames.

    That'd also be part of that whole "picking your channel mix per TP very, very carefully" consideration in doing this.
     
  4. Jul 6, 2012 #284 of 653
    ejjames

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    An example of a 5m simulsat HoTat2 mentioned. It was at the USSB uplink site east of St Paul.
     

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  5. Jul 6, 2012 #285 of 653
    cypherx

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    Yup I've seen those driving by cable companies. Neat stuff but I heard they were pretty hard to aim. The cable co that provides my Internet and Phone uses like 14 or so big dishes (D&H I think it says on them, or something like that?) They are huge but I asked why don't they just use a Simulsat and an engineer said the individual dishes are easier to aim and gives them more control. Plus they have a decent lot size that real estate isn't an issue.
     
  6. Jul 6, 2012 #286 of 653
    P Smith

    P Smith Mr. FixAnything

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    The dishes is classified as MULTIFEED dishes, not 'simulcast'.
     
  7. Jul 6, 2012 #287 of 653
    maartena

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    Also: The dishes that the cable company uses are mostly used to RECEIVE feeds from commercial satellites, so they can distribute them on their cable networks.

    DirecTV has those as well of course to receive the feeds from all over the country (including thousands of locals), but also needs a lot of dishes to send their lineup to their satellites.

    This made me go Google Earth scooping and looking up the DirecTV lot in California:

    http://goo.gl/maps/A6wD

    That's not their HQ, that is in El Segundo a little more north.... but this is where most of the "action" happens as far as satellite communication in the west of the U.S. Also looks they are well equipped: Several generators, several diesel tanks.

    Here is the facility near Castle Rock, CO where most of the action takes place:

    http://goo.gl/maps/PIDn

    Its interesting to see the size of these dishes compared to nearby parked cars etc..... I would imagine that HALF of those are for receiving feeds from all over the country, as they have to receive so many thousands of channels and feeds, and the other HALF to send them beck up. More or less. ;)
     
  8. Jul 6, 2012 #288 of 653
    HoTat2

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    Just to note:

    The image in your first link appears to be DIRECTV's "California Broadcast Center" (CBC) in Long Beach, CA. which mainly handles International programming to the 95W satellite.

    And I'd say the major hub of activity for DIRECTV's satellite communication both in the west and the rest of the nation for CONUS programming is actually co-located with their HQ in El Segundo, CA. at the "Los Angeles Broadcast Center" (LABC) here:

    http://wikimapia.org/20160436/DirecTV-Los-Angeles-Broadcast-Center
     
  9. Jul 6, 2012 #289 of 653
    cypherx

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    Wow those sites are impressive. Amazing we as a species were able to come up with such a technical marvel. I've also seen major uplink / downlink sites for Comcast Media Center in Colorado and pictures of a Dish Network uplink site. All impressive.

    Makes you appreciate these channel launches for sure.
     
  10. Jul 6, 2012 #290 of 653
    tonyd79

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    +A lot
     
  11. Jul 6, 2012 #291 of 653
    trainman

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    Not quite co-located -- the broadcast center is in Marina Del Rey (as the Wikimapia link shows), a few miles north of the headquarters building in El Segundo.
     
  12. Jul 7, 2012 #292 of 653
    georule

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    Having read this over a second time. . . just for clarity. . . are you suggesting that in your opinion, what you're seeing is adequately explained by careful matching of channels (and content on those channels) on a TP enabled with dynamic bandwidth allocation, and does not necessarily require more proficient and efficient encoders to achieve?

    Because that's what I got out of it, having mulled it over a bit more.
     
  13. Jul 7, 2012 #293 of 653
    P Smith

    P Smith Mr. FixAnything

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    Both companies doing that for many many YEARS; it's named statmux.
     
  14. Jul 7, 2012 #294 of 653
    djrobx

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    U-verse cannot do stat-mux, because the different programs shared by the downlink are dynamically chosen by the viewer.

    AT&T does not dynamically encode video just for you. There's one compressed version of ESPN-HD. When you choose ESPN-HD from your set top, it issues a command to join the ESPN-HD stream to your downlink. AT&T's routers ensure that there is enough bandwidth to deliver this to you (borrowing from the internet if needed).

    You may decide to record four high action HD sports channels at once. Your neighbors who record 1 sports channel and 3 low-action talk shows will see exactly the same quality you do. Because again, there's only one version of the encoding, and there's no way to optimize every possible combination of channels.

    DBS, cable, and even FiOS are all broadcasting a specific combination of HD channels on one downlink. At encoding time, the encoder knows for certain that it can, for instance, borrow from CNN-HD to deliver more quality to ESPN-HD if that's needed.

    The quality difference due to stat-muxing is likely to be substantial, even if overall bandwidth were equal. Something like a fast action scene, or a rapid fire scene change could benefit a lot from a short "burst" of extra bandwidth. The likelihood of unusually high activity on all 5 channels is low. U-verse just has no way to do the same thing, unless they decide to eat into the internet apportionment even more than they already do.

    Cable cannot do stat-muxing on SDV channels, for the same reason U-verse can't.
     
  15. Jul 7, 2012 #295 of 653
    veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    I guess I did get the point across.
     
  16. Jul 7, 2012 #296 of 653
    harsh

    harsh Beware the Attack Basset

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    DIRECTV uses their own satellites to uplink the LIL signals so they typically wouldn't need a large array for that kind of duty.
     
  17. Jul 7, 2012 #297 of 653
    harsh

    harsh Beware the Attack Basset

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    Compared with whomever happens to represent the state-of-the-art in real-time compression.
     
  18. Jul 7, 2012 #298 of 653
    LameLefty

    LameLefty I used to be a rocket scientist

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    Directv IS the state of the art in real-time MPEG4 compression. Comparing to MPEG2 OTA or, as some have done earlier in the thread, Blu-ray is completely apples-to-oranges. As usual, your comments add nothing to the real discussion.
     
  19. Jul 7, 2012 #299 of 653
    georule

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    Then the question becomes. . . why 6 per TP *now*? Why not years ago?

    Something has changed. I see only three realistic explanations.

    1). New, more efficient encoders.
    2). A greater willingness to risk temporary PQ degradation in corner cases when multiple channels demand high bit-rates on the same TP simultaneously.
    3). The rapid growth of HD channels, plus now years of experience/data analyzing their typical bw demands per channel, allowed D* to rejigger channel mix per TP to get 6 per without (they hope) falling afoul of #2.

    Is there a 4th possibility I'm missing? A new generation of statmux equipment that is itself more efficient/faster/better able to antcipate and priortize the dynamic allocation of bw?

    I'd like it to be #1, because that would mean the possibility, even likliehood, of more coming. If it is #3, then we can't know how much more opportunity there is for additional 6 per TP channel mixes. As to the theoretical 4th. . . dunno. At least for #1, we have an engineering presentation and a known business relationship with the manufacturer on that one. . . it's not entirely a blue-sky hypothetical.

    Just curious, the channel numbering, 1010, 1020, etc. . . would those also represent the priority list for statmuxing? i.e. When 1010 is hungry for bw, it gets first call? 1020 gets second call? etc? Presumably with minimums of some sort in place so 1050 and 1060 are at least guaranteed some bw? If so, then looking at the 1050s & 1060s would be where to focus in looking for new PQ degradation introduced by the additional load.
     
  20. Jul 7, 2012 #300 of 653
    Sixto

    Sixto Well-Known Member

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    #1 seems likely.
     

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