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SDV: Symptom Of Useless Channels Or Bandwidth Savior?

Discussion in 'TiVo Coffee House - TiVo Discussion' started by qz3fwd, Dec 11, 2011.

  1. qz3fwd

    qz3fwd Member

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    So, it seems that the need/desire for some cable companies to implement SDV is a result of several possible market/regulatory failures:

    0. With some/many cable companies elimenating analog altogether, is there really a need for SDV????

    1. Bundling of channels into packages. Most consumers only watch a small subset of the channels they pay for, and therefore subsidize the small minority of viewers watching the "others". Ala Carte would kill off quickly those "other" channels or the folks which actually watch them would have to fund the development of them. OTOH the programmers would have to survive on the income from the subset of the market which opts to actually pay for their content. If there are that few people actually watching the channels on SDV, then those channels would likely not be financially viable if left to fend for themselves? Maybe the FCC should let a free market determine which channels survive or not & ban SDV altogether?:rolleyes:

    2. Deterrent by the cable companies for consumers to use their own hardware and not lease cable company provided devices. In other words, make it as painfull as possible to discourage consumers from owning their own hardware. You know-send out scarry misleading letters to consumers that they will lose service if they dont lease cable company provided STB's/DVR's.

    3. Unwillingness of cable operators to invest in and maintain their networks. Lack of any real competition in most locales allows the cable companies to sit back, constantly raise prices, and treat subscribers with contempt all the while taking forever to enhance their networks. The use of SDV is a symptom of the cheap way out of this situation.

    Any others I missed?

    Alternatively, is SDV the savings grace for the cable companies that will provided an almost unlimited selection of channels? Isnt SDV basically identical to services like netflix/amazon except it is served over a network only accessible to the cable companies? What happens to a channel which becomes too popular on SDV and starts using too much bandwidth? Does this channel then get moved to a regular linear always on channel? For example, if there are 500,000 subscribers watching a SDV channel at the same time, would it not be more efficient to move the transport stream to non-SDV? I mean 500,000 x 12 mbps bandwidth versus 12 mbps to everyone in the regular mux? Maybe I misunderstand SDV?
     
  2. LoadStar

    LoadStar LOAD"*",8,1

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    No, you misunderstand SDV. With SDV, all the channels are transmitted over fiber from the headend to the node. At the node, however, only the switched digital channels requested by a subscriber are "turned on." When they are turned on, they are turned on to all homes connected to that node.

    It's not a unique "unicast" stream for each subscriber; it is a broadcast stream for everyone on the node. In other words, it's either 12 MBps, or nothing.
     
  3. pteronaut

    pteronaut Killer of Threads

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    How many subscribers are usualy connected to one node?
     
  4. classicsat

    classicsat Astute User

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    Both really, but heavier to the bandwidth problem.

    My observation, is at this time, providers are going to SDV to virtually add bandwidth, or removing analog to add more digital channels.

    SDV is not like Netflix/Amazon. The VOD service most providers offer os a more apt analog to online content. SDV, BTW, use the same platform as VOD, except SDV has "live" channels, rather than locally stored content.

    As for if a channel becomes popular enough, they will move it off SDV, possibly pulling
    channels off linear cable to make room.

    ETA: Loadstar has the fundamentals of SDV. If one terminal on your node selects an SDV channel and it gets switched in, anybody else that chooses to select that channel at the same time, will tune that same placement, which will stay as long as somebody is reasonalby tuned to that channel.
     
  5. CoxInPHX

    CoxInPHX COX Communications

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    The number could vary widely from a few hundred to over a thousand.

    A well designed system will be determined mostly by the number of broadband subscribers, not necessarily by video subscribers. Less than 500 broadband subscribers is a good number, any more and the provider should be looking into doing a node split. My particular node has just less than 200 broadband subscribers.
     
  6. lrhorer

    lrhorer Active Member

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    Apparently you are the one who has no a flawed understanding of SDV. This is completely false. First of all, the fiber node is nothing but a media converter witth an amplifier. (Well, actually at least two media converters and typically several amplifiers.) It has no swithing capabilities, at all. The switching occurs at the headend or hubsite.

    Once again, false. It's not a matter of turning anything on. The carriers are fixed. The bitstreams, however, are switched by a host controler.

    If you mean that every home on the node receives the same information, then that is correct.

    I don't know where you got that number. Each QAM delivers 38Mbps. Some number of channels share that bandwidth. This is true whether the QAM is SDV or linear.
     
  7. matt@thehickmans

    matt@thehickmans Hemo_jr

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    Is there an easy way for me to tell how many broadband subscribers are on my node?

    You could say that bundling channels into packages means that one or two desired channels in that package subsidize the other channels. In the same way you could say one or two desired programs on a channel subsidizes the rest of the programs on that channel -You have to purchase the channel to get the programs you want.
     
  8. lrhorer

    lrhorer Active Member

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    Nope, not even a little bit.

    Is there a need for TV at all? Television is most certainly a luxury, and could be eliminated altogether without a fundamental failure of any critical services. The demand for TV services is growing rapidly, however.

    That has nothing to do with SDV. What's more, regularly scheduled programming only represents a very small fraction of the total bandwidth of a fully developed SDV system. Video On Demand, IPPV, interactive services, and trick-play features such as "Start Over" make up the bulk of the bandwidth on an aggresive SDV deployment. It also means the cost of deploying any individual stream plummets. Already it is becoming practical for a large company to lease their own SDV channel. In the near future, it will be practical for small companies and even clubs to lease their own channel. Your local bowling league, rod & gun club, SCUBA club, or gardening club will easily be able to afford their own channel. The remainder of your point is completely specious.

    That is a much more complex situation - admittedly much of it the CATV companies' fault - than you address here. The impetus for the CATV companies to deploy SDV has a vanishinly small component related to any additinal recevues from leasing their devices, especialy since most MSOs make almost nothing directly from their leasing of STBs and DVRs. As to issues relating to 3rd party devices' inability to handle SDV well, that issue rests entirely with the 3rd party manufacturers and the FCC. It was the CE manufacturers that demanded the FCC force CableLabs to produce and support a UDCP specification. It was the CE manufacturers that did not want to be forced to support 2-way and interactive protocols, and the FCC that caved in to them. I'm not saying the CATV companies are blameless in all this - far from it - but the fact subscriber owned equipment doesn't work well with SDV is entirely the fault of the CE manufacturers and the FCC.

    You haven't even the slightest clue. MSOs have invested nearly $20 Billion in upgrading their systems, including deploying SDV. Also, you evidently have no idea what goes into upgrading a CATV system. For a comparatively modest investment in SDV, the CATV system can create a system literally capable of delivering an infinite number of channels, with unlimited growth potential for very modest additional outlays in cash. That, or for ten to fifty times as much money, they can increase their number of channels by 125, with zero growth potential.

    I'm waiting for you to come up with a single valid one.

    Not "almost". In a properly engineered SDV system, there is no upper bound to the number of "channels" that can be deployed.

    No, it's much closer to being very much like RoadRunner, AT&T, or Verizon Internet service. It's a transport mechanism, not a content provider.

    There is no such thing. First of all, if one channel gains in market share, then without fail some other channels will lose the same amount of market share. If a really large shift in popularity occurs, then hypothetically that channel might become better served by a linear QAM, and the CATV company can decide to move it to one such QAM, or not. The most popular Big Band digital modulator serves 8 QAMs, which can represent 16 HD channels and 2 SD channels. Six such modulators can serve the 96 most popular HD channels and the 48 most popular SD channels, or perhaps the 90 most popular HD channels and 81 most popular SD channels. That uses up 360 MHz. Let's assume the CTV system is delivering 90 HD channels on that spectrum, and for simplicity's sake, let's forget about SD for the moment. Now, perhaps you haven't noticed, but more than 80% of the viewing bandwidth is serviced by a mere 10 channels, leavng 80 channels to service no more than 20% of the viewing palate, with the remainder being outside the linear coverage. For argument's sake, however, let us assume over time the national networks no longer have a headlock on the viewing public, however, and the viewing coverage among the top 90 channels is nearly even. This is the worst-case scenario in terms of your proposed situation. In this case, no channel outside those 90 can possibly have a penetration of greater than 1.1%. The actual number is much lower. With a penetration of less than 1.1%, there is a fair chance any given node may not need to broadcast that stream, allowing the bandwidth to be used for some other stream. If some channel other than those 90 gains enough popularity to require more than 1.1% of the bandwidth, then it must be true that at least one of the original 90 now has a popularity of less than 1.1%, and can be moved to SDV, while the newly popular channel moves over to the linear system. 'No big deal, really.

    That's up to the CATV provider. Since they purchase modulators that host significant numbers of streams at a time, micro-managing the lineup is probably more trouble than it is worth for them. To the user, however, it is largely transpartent.

    First of all, it depends on how many subs (actually, tuners, not subs. Most subs have more than one tuner) there are, total. What's more, it doesn't even depend on that. SDV relies upon its gains for a significant number of nodes to not have any users watchihng a channel for a significant period during the day. Here in San Antonio, for example, there are many neighborhoods on the East side of town that have predominantly Black residents, while on the West side there are large areas that are almost all Latin. Both BET and Galavision are fairly popular channels here, but there is a very good chance that a large number of nodes on the East side will not have even a single viewer watching Galavision while on the West side, there will be many nodes without a single viewer watching BET. On the North side of the city, there are probably a fair number of nodes that at the very same moment have neither channel on them.

    The bottom line: Here in San Antonio, there are some 300 SDV channels. Of that number, there are only about 60 from which I ever record at all, and only about 30 from which I record regularly. That may sound terribly limited, but then consider the non-SDV channels from which I record - all seven of them - and that in all but 2 cases much less than any of the 30 SDV channels from which I regularly record.
     
  9. lrhorer

    lrhorer Active Member

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    That is an engineering / accounting decision on the part of the CATV company, and varies a lot from company to company , or even city to city. Most MSOs design their plant so that the service from a node passes between 400 and 1000 dwellings. Typical penetrations run from about 40% to about 70% in most neighborhoods.
     
  10. lrhorer

    lrhorer Active Member

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    Broadband subs, or CATV subs? The latter, no. The fomer, one can sniff the ARPs coming down the pipe and make an estimate.

    That's right. Unless the company moves to a 100% IPPV model, where one purhcases each individual program independantly, there is always going to be some level of granularity below whihc subsidies exist. That said, I dearly would love to be able to shed the cost of the national networks and such things as ESPN, TBS, etc. I have no desire to watch them and less desire to pay for them.
     
  11. lrhorer

    lrhorer Active Member

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    Correct, with the clarification that "at the same time" does not mean they have to request the channel at the same moment. Rather, if a stream is already extant and an additional sub requests that same stream, then their equipment is simply directed to tune to the existing stream. If, however, one sub is ten minutes into watching a VOD offering and a second sub requests the same movie, then a second stream on a different timeslot and probably even a diferent QAM will be initiated from the beginning. The same is true of special features like "Start Over". If a sub on TWC requests "Start Over" on a program on ABC, NBC, Fox, whatever, then the headend will spawn a separate stream for that program starting from the beginning, the fact the main channel is on a linear QAM notwithstanding.
     
  12. pteronaut

    pteronaut Killer of Threads

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    Perhaps Cable subscribers could start an "Occupy" movement to cause the self destruction of SDV.

    Have as many subscribers on one node as there are cable channels all select a different channel then have those who don't get their channel call to complain.
     
  13. lrhorer

    lrhorer Active Member

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    SDV has nothing to do directly with broadband service. The number of broadband subs and the number of homes passed are not the same thing, although 200 subs is about right for a typical neighborhood with about 450 - 500 homes passed. Only about half, give or take, of homes have CATV service in a typical neighborhood, and only some large fraction of CATV subs have broadband service.
     
  14. unitron

    unitron Active Member

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    You don't understand, we need 37 different channels showing re-runs of the various flavors of CSI and Law and Order.

    Not to mention all of those "common people being common, even if they're rich" reality shows that must run 'round the clock.

    Just like we need for everyone to have to subsidize ESPN, whether they give a sh*t about sports or not, otherwise ESPN might not be able to take the big sports events (like when local favorite teams are in NCAA March Madness) away from your local free OTA channels.
     
  15. LoadStar

    LoadStar LOAD"*",8,1

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    I would say, despite the apparent error of where the switching occurs, the basic fundamentals of my explanation are more correct than the OP's. I wouldn't say that I have "no understanding" of SDV.
    My error. I was going based on the information on Wikipedia, as unreliable as Wikipedia might be. Perhaps you might be generous enough to revise the page?
    When I said "channel," I didn't mean the carrier, I meant the bitstream. Sorry to use unclear language. (I was speaking in the colloquial, as most would refer to the "channel" as the video content you watch.)
    I was continuing with the same hypothetical number that the OP used. I didn't take the time to research whether that number was correct or not.
     
  16. rainwater

    rainwater Active Member

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    I hope not. Time Warner Cable does it right in NC. Almost every single channel is on SDV. It is part of the reason why we have so many HD channels compared to other TWC areas and other cable companies. I think we have around 110-120 HD channels (not counting VOD options).

    And there are very little issues with SDV anymore. TWC here is good about updating tuning adapters and cablecard firmware (it happens every few weeks it seems).
     
  17. unitron

    unitron Active Member

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    Unless you're one of their analog customers* whose number of channels keeps going down and whose bill keeps going up.:mad:

    *who still has lots of analog equipment that's working just fine so why spend money replacing it?
     
  18. Arcady

    Arcady Stargate Fan

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    In my city, they dumped all the analog programming and went full digital. This leaves enough bandwidth to run all of the HD programming without SDV. The only analog channel left runs information 24/7 telling you that you need a box to watch TV. I have no idea if any of the channels are clear QAM, since I only use TiVos to watch TV. For those people with analog equipment, where do you buy Beta tapes anyway? It's 2011, not 1989.
     
  19. unitron

    unitron Active Member

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    Twenty years after 1989, i.e., only 2 years ago, television was still broadcast in gracefully degrading analog before being replaced by all or nothing digital.
     
  20. Arcady

    Arcady Stargate Fan

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    General Instrument showed the first digital cable boxes in 1989. And DirecTV launched in 1994 with completely digital programming. It's not like digital TV is new.
     

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