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Letterman and Ferguson missing center channel

Discussion in 'DIRECTV HD DVR/Receiver Discussion' started by armophob, Dec 7, 2012.

  1. Dec 7, 2012 #1 of 20
    armophob

    armophob Difficulty Concen........

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    For a week or two now both Letterman and Ferguson late night shows are in DD but are missing the center channel.
    Is this a Directv thing, or is it a CBS thing?
     
  2. Dec 7, 2012 #2 of 20
    texasbrit

    texasbrit Well-Known Member

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    It's probably your local CBS affiliate. Call them (ask for the station engineer)
     
  3. Dec 7, 2012 #3 of 20
    jdspencer

    jdspencer Hall Of Fame

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    Since I record them from NY DNS and they are fine, I'd say it's your local channel.
     
  4. Dec 7, 2012 #4 of 20
    Captain Spaulding

    Captain Spaulding AllStar

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    Its always been that way here on the Dayton, Ohio CBS station. I've written to the engineers but have received no response. I've been trying to find out if Letterman and Ferguson are broadcast in DD 2.0 to begin with but have not been able to find an answer. Were you ever able to get these programs in 5.1?

    I sometimes switch the Dolby Digital setting to "off" on my DirecTV receiver so that my audio receiver will process the signal as Dolby Pro Logic, thus providing audio for the center channel.
     
  5. Dec 7, 2012 #5 of 20
    TomCat

    TomCat Broadcast Engineer

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    This is the classic situation of default mapping of DD 5.1 to stereo 2.0. If you map DD ch 1 directly to Stereo ch 1, and 2 to 2, you will get no dialog, because dialog is on ch 3 in DD. In DD chs 1 and 2 are music and EFX only, and are not the same as stereo Lt and Rt. The 2.0 downmix is created from a matrix blend of the 6 channels of DD/AC-3 (when done properly).

    But customers have no control over this. Networks and affiliates do, so the problem is probably at the station. Their equipment is supposed to handle the remapping, which is a missed setting likely in their SMPTE310 encoder, or associated audio processor/AC-3 encoder.
     
  6. Dec 7, 2012 #6 of 20
    litzdog911

    litzdog911 Well-Known Member

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    Letterman Show is broadcast in DD5.1 audio.
     
  7. Dec 7, 2012 #7 of 20
    TomCat

    TomCat Broadcast Engineer

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    Call the GM.

    If a program is not broadcast in true DD, there will be no opportunity for a bad downmix, which implies that they are.

    On the other hand, just because the DD light comes on on your AVR only means it is tagged as DD 5.1, and the 6 discrete channels you are receiving may be coming from a 2.0 source, matrixed using Pro Logic IIx at the station. Local news, local commercials, and syndicated fare is rarely in DD, while network fare rarely is not.

    Actually, no broadcaster ever really sends stereo; all (who are ATSC-compliant which includes all HD) send AC-3 only, which is the equivalent of DD 5.1. The stereo is created from those channels directly in your STB or HDTV (and that is the 2.0 downmix), or can be handled as DD using a 5.1 decoder.
     
  8. Dec 7, 2012 #8 of 20
    armophob

    armophob Difficulty Concen........

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    What makes me mad is the commercials bounce right back to proper 5.1.
    I am just glad that any regular series are all over now.
     
  9. Dec 8, 2012 #9 of 20
    TomCat

    TomCat Broadcast Engineer

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    What they really "bounce back to" is simulated 5.1 from their original 2.0 source. Stereo sources don't have the issue unless the DD simulator is wired really, really, improperly to begin with, and most commercials, even in 5.1 programs, are stereo.

    Part of the problem is that local TV Engineers install this sort of equipment in the daytime, when much of the content is 2.0. After they go home is when the 5.1 sources come into play, and by that time the damage finally manifests itself.

    But most incidents are a mixing problem at the source. Again, unless they QC BOTH the 5.1 and 2.0 downmix, those folks are also long gone before the problem reveals itself,
     
  10. rsblaski

    rsblaski Icon

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    Last time I saw him , I could only hear Letterman talking from the (far) left.
     
  11. juniormaj

    juniormaj Legend

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    Newbury...
    In Los Angeles (KCBS 2), Letterman and Ferguson have been stereo inside a 5.1 stream for as long as I can remember.
    The dialog is not missing, but is part of the stereo mix. However the stream is presented as 5.1 to my receiver.
    Stereo L and R. Surrounds, center, and subwoofer are silent.
    Those 2 shows are also a bit quieter than other programs.
    The commercials do often fill all the channels.
     
  12. RunnerFL

    RunnerFL Well-Known Member

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    I record Ferguson via OTA and don't experience this. I'll try the SAT signal this week and let you know since I'm sure we're watching the same channel. 12?
     
  13. armophob

    armophob Difficulty Concen........

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    Fort Pierce, FL
    Yep, I noticed it in the commercials of a recording of Hawaii 5o as well.
    But it was a few weeks old.
     
  14. RunnerFL

    RunnerFL Well-Known Member

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    Ok, I've got Ferguson set to record tonight via SAT, and OTA, so I'll check it out and let you know.
     
  15. TomCat

    TomCat Broadcast Engineer

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    Wow. These are even more stupid screwups. A missing channel is a missing channel and probably has nothing to do with 5.1. A 5.1 metadata tag with sound only from L and R sounds like they downmixed 5.1 to 2.0 then mapped it incorrectly (without the normal upmix) to 5.1 once again. The steering logic is what makes it sound lower in that case, and if the commercials are full, those are probably 2.0 mapped directly to 2.0. They would then be louder.

    Odd that a station of that caliber would have this problem. I'd be fired if I presented a pattern of screwing the pooch that badly.

    The CALM act goes into affect this Wednesday, December 13th. If your station has loud commercials after that date and you complain to the FCC, they will spank them but good.
     
  16. juniormaj

    juniormaj Legend

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    Newbury...
    I'll check the next time I get a chance, but I think the commercials are in true 5.1.
    I'll look to see if it is switching to ProLogic or staying "straight".

    --- edit

    Monitored the first half hour of Letterman on KCBS2 via DirecTV and via Time Warner (as an option to eliminate DirecTV as the culprit). Same results on both.
    Switched Yamaha receiver to "Straight" mode, which will not process the signal with any surround decoding. It only passes the source stream.
    This way, if the signal were to switch to 2.0 I would see it on the receiver's display.
    The signal stayed 5.1 the entire time from both DirecTV and Time Warner, but only 2 of the commercials actually utilized all 5 speakers (plus subwoofer).
    Most of the time (as noted) there were only 2 active speakers (L and R).

    Local news: Stereo inside 5.1
    Letterman: Stereo inside 5.1

    commercial break 1
    Apple, Netflix, Advil PM, Walmart: Stereo inside 5.1
    Iams Catfood: True 5.1 (all channels active)
    Django Unchained, Subaru, Las Vegas Tourism: Stereo inside 5.1

    Letterman: Stereo inside 5.1

    commercial break 2
    Target, Olive Garden, Kayak.com, Chevrolet: Stereo inside 5.1
    Capitol One: True 5.1 (all channels active)
    Pringles, Target, CBS Vegas, Silver Linings Playbook, Dodge, Promised Land: Stereo inside 5.1

    Letterman: Stereo inside 5.1

    and so forth

    On the Ferguson show, there were similar results.
    The first commercial break had only one true 5.1 commercial. It was the first one of the break and it was for Progressive.
     
  17. RunnerFL

    RunnerFL Well-Known Member

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    armophob,

    I'm watching last night's Ferguson, recorded via SAT, right now and I have center channel audio.
     
  18. armophob

    armophob Difficulty Concen........

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    Fort Pierce, FL
    Me too, they fixed it. Must have heard me bi***ing. :)
     
  19. RunnerFL

    RunnerFL Well-Known Member

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    hahaha, so I recorded it after it was fixed. Nice!

    btw, I was waiting for the Grinch Armophob to make an appearance!
     
  20. armophob

    armophob Difficulty Concen........

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    Nov 13, 2006
    Fort Pierce, FL
    yea, the xmas movie thread brought him out

    And I bought some Wendy's for lunch and was told to enjoy xmas.
    I am done already and it is only the 12th
     

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