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SDV FAQ

Discussion in 'TiVo Series3 HDTV DVRs' started by bdraw, Jul 3, 2007.

  1. Jul 3, 2007 #1 of 2401
    bdraw

    bdraw Member

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    What is SDV?


    SDV stands for Switched Digital Video, a scheme where not all TV channels are broadcast out from the cable headend to the homes that it serves all of the time. This is attractive to cable companies, because they can offer more TV channels than their cable plant has the bandwidth to broadcast. For example, your cable company may have 10 different channels in your lineup, but only 5 physical channels to send them from the headend to the houses they service. This requires a cable box that can communicate back upstream to the headend and say “I would like to watch ESPN2HD now” and then headend would take that request, assign it to a frequency and then tell the cable box “ESPN2HD is available on xxx,xxx kHz”

    [​IMG]


    What does this mean for the Series 3, Tivo HD and TiVo Premiere?


    With out an additional Tuning Adapter supplied from the provider, the Series 3, Tivo HD and TiVo Premiere is not able to communicate upstream to the cable headend, so it cannot send the request for channels that are assigned to SDV. Users of the S3 and THD will not be able to watch or record any of these channels.

    Which channels will be converted to SDV?

    Traditional methods send every channel to everyone, and if no one on your head-end is watching that channel, the bandwidth is effectively wasted. SDV allows them to turn off that channel when it's not being watched so that another channel can occupy that bandwidth. If a channel is always being watched it will probably never be converted to SDV. So the less popular a channel is, the more likely it will be converted to an SDV channel. See this Multi-Channel news article. That being said, there are some providers who use SDV to deploy a very large number of channels, though.


    The solution

    The NCTA and TiVo worked together for over a year and finally the first working solution has reached TiVo owners in NJ on Comcast. The device from both Cisco and Motorola are called Tuning Adapters (formerly known as Tuning Resolvers) and connect via USB to the TiVo (9.4 or higher) and feature pass-through coax connections, so a splitter is not needed. So when you attempt to tune a channel delivered using SDV, the TiVo sends a signal via USB to the Tuning Adapter which sends the signal via coax upstream to the providers head-end. This turns the channel on and returns the tuning information back to the TiVo.

    In a demo at the Cable Show a few years ago I had a chance to play and was not able to notice any difference in speed when changing channels that were deployed with traditional QAM or SDV.

    Depending on the head-end there are two solutions, Motorola and Cisco (formerly Scientific Atlanta). If your operator hands out Cisco set-top boxes, then odds are they'll use a Cisco TA.

    The Cisco STA1520
    [​IMG]

    The Motorola MTR700
    [​IMG]

    Some providers are offering these for free, but some charge at first or after a few months.

    Here is TiVo's FAQ that address the Tuning Adapter.

    Here is Time Warner's FAQ about the Tuning Adapter.

    San Antonio TWC customers can pre-order their Tuning Adapter from here.

    Here is some of the history of the Tuning Adapter, formerly known as the tuning resolver:
    http://www.tivolovers.com/2007/05/10/mr-tivo-goes-to-washington
    Here is TiVo's official info on the adapter.
    http://tivosupport2.instancy.com/LaunchContent.aspx?CID=CBECF1B9-88DE-4B74-82C1-754C3260112A
    CableLabs press release about USB dongle
    http://cablelabs.com/news/pr/2007/07_pr_dcr_devices_112607.html
    NCTA and TiVo press release
    http://www.prnewswire.com/cgi-bin/s...11-26-2007/0004711019&EDATE=#linktopagebottom
    Of if you want to do something about it, report your missing channels to the FCC.
    http://www.fcc.gov/cgb/complaints_general.html


    What about FIOS?


    Right now, because of the fact that FIOS uses fiber optic cable to your house, FIOS has no plans to deploy SDV – they have instead chosen to invest in expanding their QAM RF overlay infrastructure and use IPTV for PPV and VOD.

    Where is SDV located right now?

    SDV deployments are changing very rapidly and impossible to track, in fact even most of the CSRs don't know if their company uses SDV and even if they do, not which channels.

    Tuning adapters are here to stay
    TiVo has asked the FCC to modify the rules pertaining to 3rd party CableCARD devices and eliminate Tuning Adapters. The proposed solution was to allow the TiVo to communicate via IP to the operators servers to perform the requests that are currently handled by the TA. This would've require that you have internet service from the same provider, but would eliminate a set-top box from the equation.

    TiVo claimed it was necessary to increase reliability and would reduce costs for the operators. The NCTA and its members claimed that the TAs are well accepted and supported and it is not necessary to make any changes.

    The FCC determined that it would rather not mandate a specific solution, but instead mandated the SDV channels work for CableCARD users and will be making it easier to report issues so that consumers could help enforce the mandate.
     
  2. Jul 3, 2007 #2 of 2401
    That Don Guy

    That Don Guy Now with more GB

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    Pardon me for asking, but could you confirm that this is, in fact, the "complete" Versus and Golf Channel sharing your channel 694 (in which case, how do you choose between the two), as opposed to the Vs/Golf HD channel (which is a single channel that shows some Golf Channel shows and some Versus shows)?

    -- Don
     
  3. Jul 3, 2007 #3 of 2401
    bdraw

    bdraw Member

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    Honestly I don't know since I can't watch it, but according to BHN's website it's the Versus HD+ (7pm-12pm) everyday but Thursday/Friday when it's (12am-12pm). Then it's the Golf Channel HD+ (12pm-7pm) everday but Thursday/Friday when it's (12pm-12am) .
     
  4. Jul 3, 2007 #4 of 2401
    That Don Guy

    That Don Guy Now with more GB

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    That's not SDV - it's two networks airing at different times on the same channel.

    SDV allows for more than one station to be accessible through a single channel (although just one at a time). The problem as far as TiVo is concerned is, there needs to be a way for the tuner to tell the cable system which of the multiple channels to air at any particular time - something a TiVo cannot do.

    Pardon me for going off on a slight tangent, but does anybody out there know more specifics as to how SDV would work? Would each SDV channel have an on-screen menu of some sort, and the viewer would select which station to watch on a particular channel, or would different channel numbers be mapped to the same physical channel somehow?

    -- Don
     
  5. Jul 3, 2007 #5 of 2401
    bdraw

    bdraw Member

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    Don,
    You can't tell it's an SDV channel if you have a standard digital cable box. I know it's SDV cause I called BHN to ask why I wasn't receiving the channel and they told me that the channel doesn't work with CableCARDs since they are one way (in many more words).

    The fact that the channel splits it's time between two networks has nothing to do with the fact that it's an SDV channel.
     
  6. Jul 3, 2007 #6 of 2401
    GoHokies!

    GoHokies! O2->CO2 Converter

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    KFME
    Since Ben hasn't been able to keep up with the SDV reports in the OP, I'm going to keep this post updated with reports from the forums:


    TWC Cincinnati:
    http://www.tivocommunity.com/tivo-vb/showthread.php?p=5460259&&#post5460259
    TW Hawaii:
    http://www.tivocommunity.com/tivo-vb/showthread.php?t=364085
    TW Myrtle Beach:
    http://www.tivocommunity.com/tivo-vb/showthread.php?p=5327449&&#post5327449
    TWC Albany:
    http://www.tivocommunity.com/tivo-vb/showthread.php?p=5424033&&#post5424033
    COX Fairfax (VA):
    http://www.tivocommunity.com/tivo-vb/showthread.php?p=5468367&&#post5468367

    I actually started writing a post in notepad a few days ago on this exact topic (including what SDV is for those that aren't sure). One of the mods said that he would sticky it if there was value.

    SDV FAQ moved from here into the OP. :D

    Here's the full text of the URL for the OP:
    http://www.tivolovers.com/2007/05/10/mr-tivo-goes-to-washington
     
  7. Jul 3, 2007 #7 of 2401
    SugarBowl

    SugarBowl Member

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    searching the Time Warner Raleigh website for "Switched Digital" gives 1 hit. And that hit is a graphic for cable cards saying that cable cards can't get switched digital channels. I haven't tried, but I suspect if I call customer service and ask about these SDV channels, they will have no clue what i'm talking about.
     
  8. Jul 3, 2007 #8 of 2401
    bdraw

    bdraw Member

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    If you have links, please submit them.

    GoHokies,
    If you don't mind I'll copy your great SDV synopsis into my first post.
     
  9. Jul 3, 2007 #9 of 2401
    GoHokies!

    GoHokies! O2->CO2 Converter

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    KFME
    Not at all, you beat me to the punch. :D

    I'll post up some of the links that I found the info from also.
     
  10. Jul 4, 2007 #10 of 2401
    MickeS

    MickeS New Member

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    The link to http://www.tivolovers.com/2007/05/10/mr-tivo-goes-to-washington/ doesn't work in your copy of GoHokies post, since you just copied the text (that doesn't copy the actual URL), so you need to edit that URL to make it work.

    Thanks for the writeup. :)
     
  11. Jul 4, 2007 #11 of 2401
    jrm01

    jrm01 New Member

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    Good idea to get all of this into one post. However, in your definition of SDV you describe it as the switching ocurring at the cable company head-end. I thought most of the switching has been done at a "neighborhood junction box" of some kind, e.g. the cable company runs fiber to some point in a neighborhood, then coax to houses, and the switching was done at that junction.
     
  12. Jul 4, 2007 #12 of 2401
    bdraw

    bdraw Member

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    Jim,
    Exactly, and that junction box is sometimes called a headend, but I see what you mean, maybe someone in the cable industry and clarify.
     
  13. Jul 4, 2007 #13 of 2401
    GoHokies!

    GoHokies! O2->CO2 Converter

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    That's what I thought that it was called, and I hoped that someone would come along and correct some of my mistakes. :D I had the right idea, and the wrong terminology.

    Looks like I have a little bit more learning to do :D
     
  14. Jul 4, 2007 #14 of 2401
    bdraw

    bdraw Member

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    I've always called it a headend as well. The illustration calls it a distribution hub, which is new to me. Either way there are 500-2000 people all using it.
     
  15. Jul 4, 2007 #15 of 2401
    vstone

    vstone New Member

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    Martinsville...
    Go to the scientific Atlanta web site and search for SDV and you'll find several articles talking about SDV and SA's equipment. I assume it's roughly parallel to Motorola's eq.

    AIR, the SA docs can be read to say that the control info is routed via TCPIP. If so, an S3 fix might be relatively easy.
     
  16. Jul 4, 2007 #16 of 2401
    bdraw

    bdraw Member

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    vstone,
    Technically, I'm sure the fix is really easy; but politically, not so much.
     
  17. Jul 4, 2007 #17 of 2401
    classicsat

    classicsat Astute User

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    Simply each SDV channel will have a channel number like any other channel, and from the users perspective, work like that too. It is just underneath, the box knows instead to tune that channel, it has to ask the headend (or node if you will) for it, which the node controller will place the channel on the node, if not yet selected by another user on the node, and tell the box which channel/subchannel to tune to get it.
     
  18. Jul 4, 2007 #18 of 2401
    vstone

    vstone New Member

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    Martinsville...
    I couldn't agree more!
     
  19. Jul 4, 2007 #19 of 2401
    vstone

    vstone New Member

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    Martinsville...
    In some, perhaps many, places, cable plants used to populate the datastream with enough information to tell you that, for example, you tune to channel 707 to get the local HD CBS broadcast. This information is being deleted from the data stream. It could be that they are doing this to make clear QAM tuners look bad. They could also be doing this because of SDV. Any thoughts?
     
  20. Jul 4, 2007 #20 of 2401
    sfhub

    sfhub Active Member

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    I believe the FCC regulations state they must pass through any PSIP from the OTA when they rebroadcast OTA on cable.

    Other than that, I don't believe they are required to populate PSIP info.
     

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