Is my digital cable really digital?

Discussion in 'Archived Threads 2001-2004' started by William_L, Jan 8, 2002.

  1. William_L

    William_L Extra

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    I was wondering that since my Digital cable box doesn't have any digital outputs, am I really getting digital audio?

    The box is made by GI, and the only outputs are RCA and the usual coax. There is an S-Video marking on the back, but only a marking, there is a knockout where the S-Video output should be.

    I have an Onkyo 595 receiver, and the only time I ever see a Dolby Digital or DTS display is when playing a DVD with the digital optical cable

    I questioned the cable company (AT&T) about it, but of course they had no idea what I was talking about

    I'm not sure of the model of my 'digital' box, but it does have the Dolby Digital logo on the front
     
  2. Brian Fellmeth

    Brian Fellmeth Supporting Actor

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    Where I live, the "digital cable" thats offered where I live is not digital at all except for menus, schedules. Both the sound and picture are analog, no bitstream in or out of the cable box. I suspect your cable company is doing the same thing.
     
  3. Pamela

    Pamela Supporting Actor

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    There seems to be a lot of people who have boxes with the Dolby Digital logo on the front without the output on the back. I suppose they have the capability for DD, but lack the outputs.

    I have Charter Cable. Both of my Scientific Atlanta boxes have digital coaxial outputs and they work. I have watched some stuff on HBO and Showtime in DD and they sounded great. Most programs are broadcast in plain old anaolg, though.

    I have asked them technical questions about their digital services and they've given me some pretty silly answers.
     
  4. PatrickM

    PatrickM Screenwriter

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    I have the Motorola box which is GI now that Motorola bought them. It happens to have a SPDIF output for DD but it also has a DD decoder inside for DD 2.0. on the digital channels.

    Here in Vancouver the channels from 2 to 59 are analog in video and audio but starting at 60 they are digitaly compressed video and DD audio. I suspect many other cable system out there are similar.

    Patrick
     
  5. Robert Cranwell

    Robert Cranwell Stunt Coordinator

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    Willam, most of the GI digital DCTS boxes only pass on the upconverted NTSC picture. Alot of them suffer from not having a SPDIF / Digital audio output. Rob
     
  6. Sheldon C

    Sheldon C Second Unit

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    I have Time Warner Cable in Kansas City. I get digital sound (I do have a coax digital out) on all digital teir channels. I get 2.0 on most of them, but on HBO 1 which has two channels, I get 5.1! Even better, Showtime puts out 5.1 on all their channels (around 10 of them) as long as the movie is being broadcast in 5.1. Basically almost every movie made in the last year or two is being broadcast in 5.1 on these two channels.
     
  7. William_L

    William_L Extra

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    I actually have 2 different boxes, one by GI and the other by Motorola, both look identical, and neither one has any type of digital output. I do know that we are due to have fiber installed in my neighborhood by march, and most likely will be getting new boxes (I was told this by the cable guy last week, when I had them at my house again)
    I guess I'll have to wait and see if these will actually be digital. In the meantime, I think I may call the cable company up again (Once when I called asking about the S-Video output, they sent a tech to my house with a set of stereo RCA connectors, thinking that is what I was talking about [​IMG]
     
  8. Bob McElfresh

    Bob McElfresh Producer

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    Uhhhh guys - "Digital Cable" service and "Dolby Digital/Digital Output" are very different things.
    A "Digital Cable" service allows your CATV company to push more channels to you over existing/crappy coax. This prevents them from having to upgrade the coax in an area, and they can shove more Home Shopping channels at you.
    For some channels, your local CATV office has an ANTENNA that receives a local station, digitizes the signal and pushes it through the coax.
    Even if your CATV company has a sat dish to take a network/HBO signal as a digital feed, it has to convert it to ANALOG, then re-digitize it for the trip through the coax to your set-top box. (Can you say "Generational Loss"?)
    AFAIK: the digitization/compression scheme is custom to whatever system your local CATV company has purchased.
    Some of the set-top box's include a option for a Dolby Digital output. So these box's have the "Dolby Digital" logo on the front. Some CATV companies purchase the option to un-cover/turn on this output. Other CATV companies figure that the logo is enough to fool J6P and dont uncover the jack. (Digital is Digital...right? Not really.)
    Even if the option/jack is turned on, here is what I suspect happens to the signal:
    • The CATV company receives the signal (lets say it's a digital feed to give them the benifit of the doubt).
    • The CATV equipment converts the signal to ANALOG.
    • The CATV company then compresses the signal to it's internal digital format and pushes it to your set-top box.
    • Your set-top box converts the signal back to ANALOG to drive the composite/L/R jacks.
    • A chip in the set-top box takes the ANALOG audio signal and converts it to a Dolby Digital bit-stream.
      But the source is a 2-channel ANALOG signal. This means you get a Dolby Digital 2.0 signal. So you will NEVER see "Dolby Digital" on your receiver, just "ProLogic".
    All the digital->analog->digital->analog->Dolby Digital conversions is not good for the sound.
    And lets face it: your CATV company has zero incentive to send a 5.1 signal to your TV. It would take away channel space that they could use for more Home Shopping/QVC/Shopping Network/Mens Channel/... which they get PAID to offer.
     
  9. David John

    David John Stunt Coordinator

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    I don't agree with your assesment.

    First off, I get Dolby Digital in full 5.1 over my digital cable (Time Warner NJ) with a Scientifc Atlanta box.

    All the digital channels have DD 2.0 signals, and the analog channels have analog audio.

    The DD5.1 are only from HBO and Showtime when they broadcast it in 5.1. There is full screen they show before a 5.1 broadcast that says "The following is brought to you in Dolby Digital 5.1 Surround".

    My cable company delayed their implementation of Digital cable for a while because of hardware issues. But they got it right when they finally did it.

    So I don't think your info is correct. Perhaps that is the way your local cable company provides your signal, but it may not be for all.
     
  10. PatrickM

    PatrickM Screenwriter

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    Bob, some of your points are correct but some are incorrect depending on the cable system in question. The cables systems up here have gone to great lengths to create a fibre optic ring distribution system and upgrade all coax to the home to the 900MHz range at minimum.

    Rogers back east has even announced the introduction of HDTV on cable.

    And the compression scheme is pretty much the same for both the S/A and Motorola boxes. S/A and GI agreed to this quite a few years ago before GI became Motorola. The encryption/coding schemes are different though.

    Patrick
     
  11. Gary Tjia

    Gary Tjia Stunt Coordinator

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    Anyone in Minneapolis know if Time Warner Digital Cable has 5.1 digit sound for SHO and HBO? I just got my box yesterday and my Marantz SR7000 did not pick up any 5.1 signal when tuned to SHO and HBO.

    Also, the digit audio output from the EXPLORER box is not for Optical cable.

    Please share your thoughts. Thanks.

    Gary
     
  12. William_L

    William_L Extra

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    Just an update from my original post. I called ATT yesterday, and after about 20 minutes with the rep, I was told that, yes, I can bring in my current box and exchange it for one with s-video (hey, it's a start!) Still no type of digital audio outputs, but I figured I might as well go exchange it.
    So I pulled the box, removed all the cables, and headed on down to exchange it. I told the girl I was there to exchange this box for one with s-video, and her words, "oh no, not this s-video thing again". Then she proceeded to tell me that NONE of their boxes are have s-video.
    I was ready to drop my cable service right there, and tell them I'm getting a dish. I pay over $70 a month for cable in stereo? What is this, 1999? [​IMG]
     
  13. Sheldon C

    Sheldon C Second Unit

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    Bob, I was not lying with my earlier post. In my area I do get 5.1 dolby digital on some HBO channels and all Showtimes as long as the movie is being sent out in 5.1. It doesn't sound as good as a dvd, but it's pretty close.
     
  14. Gary Tjia

    Gary Tjia Stunt Coordinator

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    Sheldon,

    The Time Warner Digital cable box I have only has a digital coxial audio output and analog audio output for sound. The digital audio signals I have seen so far are 2.0, not 5.1. Maybe they do not have 5.1 audio available in Minneapolis, MN yet.

    Gary
     
  15. Todd Hochard

    Todd Hochard Cinematographer

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  16. Jim Lenneman

    Jim Lenneman Stunt Coordinator

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    Here's my experience FWIW. I have "digital cable" provided by a new, strictly local provider who installed fibre optic cable. Originaly, I was provided a General Instrument box (DCT-2224) which did not have s-video or digital audio (SPDIF) connections. Recently, I was able to get them to provide a Motorola DCT-2224 box (Gen Inst is now Motorola so same basic box) that does have s-video and an SPDIF connection. The video is much improved, and it was damn good before. The audio is digital, but here's the rub. It's PCM digital, but not capable of providing 5.1. After some research on Motorola's web site, it appears from the cable box descriptions that the DCT-2000 series will pass a digital signal, but the DCT-5000 series is the only one which will pass DD 5.1.

    Jim L
     
  17. Brian Kleinke

    Brian Kleinke Supporting Actor

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    Here's my setup -- digital in a way [​IMG]
    I'm receiving my TV signals through the phone company. Basically I have a fat DSL pipe coming into my house of which part is used for my computers DSL connection and the rest supports 3 TV feeds. The black box has a DD sticker on it and a DD toslink connection on the back. However the phonecompany decided to give us 3 feeds instead of 2 + DD. The single is likely analog at some point but comes to me as MPEG so instead of snow I get tiling sometimes [​IMG]
    Brian
     
  18. Duane M Davis

    Duane M Davis Stunt Coordinator

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    Duane Davis
    I have Warner Digital Cable in Columbus OH and get HBO in 5.1, but only for certain movies.
     
  19. Jason Wolters

    Jason Wolters Stunt Coordinator

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    Must be nice to live in civilization.[​IMG] I wish I had TWC. So most of you are watching your network stuff in analog right??
     
  20. Steve Castle

    Steve Castle Auditioning

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    I too have that DCT2224 Motorola unit. Everytime I've called AT&T to try to get them to give me a new box they give me a run around and I eventually get no where. Once they passed me off to someone who fed me stuff about how things may be different after the Comcast merger. But still no box. Has anyone been able to shake a better cable box out of AT&T? If so, how'd you do it?
     

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