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SDV FAQ

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

  1. lrhorer

    lrhorer Active Member

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    'Total nonsense.

    1. Ethernet is no more complex than USB at any layer.

    2. If Ethernet had been implemented, it is likely it would not have been impolemented at the IP layer. There would be no real need. More likley it would have been implemented at layer 2, and the TA would not have participated at the IP layer at all.

    3. Security at layer 2 would not be required. There is little or no point.

    4. USB is not fundamentally any more secure than Ethernet.

    5. Implementing security in a USB device carries precisely the same requirements as in an Ethernet device.
     
  2. lrhorer

    lrhorer Active Member

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    That was the reason given, but it is completely specious.

    Having a USB port does not mean there is a means of obtaining a data path between the CableCard and the USB port. I doubt even a single TV out there is capable - even with a software upgrade - of forwarding tuning requests to the USB port.

    I think that's a very tiny "if". It's possible some new TVs might come out with support for the TA, but adding an Ethernet port would be no more difficult than adding TA support via USB for a model in development. It's possible some manufacturers might offer a hardware retrofit, and there even might be a couple of sets out there which could be made to work with a software upgrade, but I'm skeptical.
     
  3. emily12

    emily12 New Member

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    Aug 14, 2008
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  4. mikeyts

    mikeyts Stream Warrior

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    TA support doesn't actually require a data path between the CableCARD and USB port--the UDCP talks to the TA solely through the USB connection and forwards any information that the TA needs about the CableCARD over that path. I assume that these products (consumer TVs and STBs) have some central processor responsible for UI functions, listening to remote commands and formulating tuning requests--if that processor also handles communication with the USB port, TA compliance can be implemented. (I know that that's the basic architecture of TiVo).

    There may be a handful of televisions out there which could potentially be upgraded to support it, which included USB ports for various reasons. I can't remember who, but I remember that at least one company produced some televisions which could accept firmware upgrades written to flash cards (the other use for the flash card slot was display of pictures from digital cameras)--you could download upgrades from their site, write the files in the appropriate directory of the flash card and upgrade your firmware that way. There's some company out there selling a system for upgrading firmware in devices with television tuners with files downloaded through ATSC datacasting streams--some OEMs have signed up for the service.

    If there are CableCARD-equipped televisions with USB ports and easily field-upgradable firmware that could be modified to create TA compliance, there will damned few of them. Would it be worth upgrading them for TA compliance? I suppose that their owners could be notified that their model could be upgraded for TA compliance in the same way that the cable providers have been notifying TiVo users--by sending letters to every CableCARD using sub with the information, listing upgradeable television/STB models and giving URLs and/or television numbers of where to go for more information.
     
  5. vstone

    vstone New Member

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    I have a 26" Panny in the bedroom (purchased July 07) that can be upgraded with a memory card like the one in my camera (but no USB slot). I presume that is available across the entire Panny line. However, I think the only CEM still putting cablecard slots in their TV sets is Mitsubishi.
     
  6. mikeyts

    mikeyts Stream Warrior

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    If any products are upgradeable to TA compliance, they'll be few if any of last year's models. Unidirectional CableCARD was a failure, much to the credit of the cable providers (and the FCC, for giving them a 2 year grace period on the requirement that they use them in their own equipment). And you're right--I don't think that any of the OEMs other than Mitsubishi put CableCARD slots in their 07/08 model lines (those 07/08 Mits TVs with CableCARD slots all have USB ports as well, for viewing photos from USB flash drives and card readers and hints in the manuals would indicate that the port can be used for software update--they may be eligible for a TA-compliance upgrade). The CE OEMs all manufactured millions of televisions with CableCARD slots and the NCTA claims that only a few hundred thousand CableCARDs have been leased nation wide.

    BTW, I remembered the company that's marketing that update-firmware-through-broadcast tech--it's called UpdateLogic.
     
  7. jeffspam

    jeffspam New Member

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    Feb 27, 2001
    Dublin, OH
    Well, it looks to me that TWC in Columbus, OH is turning to SDV, which means I've got about 61 pages of this thread to catch up on. The whole argument of USB vs Ethernet interests me though. Really, why need an external adapter at all? If the device (i.e. my tivo) already has broadband connectivity, it should communicate directly with the headend equipment via IP to request the channel be setup. Same should be true for any two-way service (e.g. VOD). I'm sure this has been brought up before somewhere in this thread, but it seems to me that needing anything external to the Tivo is a waste.

    That said, I'm certainly curious when these adapters will be released, or more importantly, when my local CATV company will stock and distribute them. I'm not holding my breath.
     
  8. shabby46

    shabby46 New Member

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    Aug 3, 2008
    Falls...
    Maybe this has already been addressed but I didnt see it, so let me see if I understand this correctly...

    Where I live (cox fairfax) SDV is now taking up about 25 of the 40 HD channels. They are saying that the tuning adapter is not rushed because there isnt much of a demand for it as very few people have tivos. The reason for SDV is to save bandwith, so if it is known that I have cablecards and I am one of the very few people in the area who has it, couldnt there be a way to have our (CC users) HD channels sent to us all the time which would barely use any bandwith since there are so few of us? At least until the TAs are available?

    At the very least they could let me pick which HD channels I want to receive and have those turned on all the time. I can deal with OTA networks for now, but I miss Discovery and Food HD.
     
  9. classicsat

    classicsat Astute User

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    Ontario Canada.
    Simply, the IP channel from the ethernet or wireless adapter on the TiVo is an unknown quantity (as far as security and identity goes), plus the cable providers would have to set up a web based back end to support it, not to mention a more complex software layer on the host device. The Tuning Adapter, as currently designed, connects locally to the host, using a rather simple and standard protocol, and requires little change to the cable head/back end, perhaps just marrying the serial number of the TA to the cablecard(s) in the host, if it doesn't marry itself to or assume the identity of the host cablecard.

    The providers cannot send channels to particular providers, but at most to a node, and that does take up bandwidth, and work to administer just for a handful of customers, so will not happen.
     
  10. mikeyts

    mikeyts Stream Warrior

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    There may only be a few CC users in any given area (and by "few", we're talking about, say, 2000 of 200,000 subscribers on a system), but they're probably spread randomly throughout the system, with some on many, if not most, network edge segments.
     
  11. jeffspam

    jeffspam New Member

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    Feb 27, 2001
    Dublin, OH
    Certainly security certificates and encryption, which devices such as the Tivo already make use of, can handle this part.
    Why web-based? A simple server in the racks at the headend, doing all the authentication and communication with the consumer devices (e.g. my Tivo), could relay requests into the headend equipment. As far as the headend equipment is concerned, it'd be seen just as if a cable box had made the request. And as far as the Tivo (or whatever) goes, it just puts a simple request ("I"d like to reserve channel 632 for 1 hr") into an authenticated wrapper and opens a port to the (let's call it...) SDV translation server. The server sends back a yea or nay, and Bob's your uncle (I've always wanted to use that phrase. Apologies.).
    Anyway, just a thought. I would think it'd be a lot easier to do this than deploy yet more equipment to end users, but I suppose I should have applied for a membership to CableLabs a while back.
     
  12. JayBird

    JayBird New Member

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    Jan 25, 2003
    Gilbert, AZ
    The Pioneer KURO Plasmas had cable card slots up until the latest models that were just released in the last couple of months.
     
  13. lrhorer

    lrhorer Active Member

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    I figured you might nit about that. It's true no data comes directly from the CableCard to the modulator. Rather, data passed to the CPU by the CableCard is acted upon by the CPU sending packets to the moduator. It's definitely an indirect path, but it also requires the processor be able to act upon data from the CableCard and send out data to the USB port. I expect many TV's have the CPU instructions on PROM, not in non-volatile RAM. Others may use different dedicated systems for the two, since the CableCard in a UDCP isn't expected to send data out the USB port.

    Yes, but I suspect many times that may not be the case, and even if it is the case, the firmware may not be downloadable.

    A very small handful, I think.

    I think my Mitsubishi is supposed to work that way, as I recall, but I never have found the software on their website. OTOH, I haven't looked in almost 2 years, either.
     
  14. lrhorer

    lrhorer Active Member

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    'Not to save bandwidth, per se, but to increase it manyfold. In short, it allows the CATV companies to potentially provide literally thousands of channels to their customers at an extremely low cost to the CATV provider per channel.

    That is just the oppostite. What you are proposing woud use much more bandwidth, not less, than SDV. Indeed, it is essentially just a regular linear channel. The bandwidth is the same whether 1 person is watching the channel or 100,000. Besides, how would the CATV company's equipment know where the TiVo owners are?

    You seem to be misunderstanding not only how SDV works, but also how legacy linear broadcast channels work.
     
  15. lrhorer

    lrhorer Active Member

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    This is total nonsense. 'Give the TA a MAC address and ARP or similar capability, beacon from the Tivo to find a TA using the same ARP or ARP-like protocol, and from then on send all packets to the MAC address found by the TiVo. The TA then simply passes on any non-ARP packets to the modulator. 'Trivial.

    The 802.1 specification is every bit as much a standard as USB. The Universal Serial Bus architecture is in no way any less complex than Ethernet. Finally, they are both bus architectures (notice the name: Universal Serial Bus) allowing multiple devices to be attached together in a single segment.

    Since IP is layer 3, it can be transported over any sort of lower layer protocols, including Ethernet, Token Ring, Arcnet, SLIP, PPP over RS-232, RS-445, DS-1, DS-3, OC-3, OC-12, or PPTP, IPSec, L2TP, etc., or last but not least, USB.

    It does nothing of the sort. All it does is provide layer 2 bridging from the host network segment to the CATV network segment. This only requires that it recognize data coming from the host as being destined for the CATV network and pass it on. It will ignore any data not destined for the CATV network (or the TA itself). This is its function whether it is Ethernet based or USB.

    (I think you meant "...to particular subscribers".) Well, they could, and indeed this is precisely what Uverse does, and FIOS's implementation of VOD, as well. SDV is generally a more attractive alternative for the CATV topology, however. In a CATV plant, it makes best sense to put the switch boundary at the node. Anywhere else is much less efficient. IPTV puts the switch boundary at the subscriber's dwelling.
     
  16. mikeyts

    mikeyts Stream Warrior

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    As I said, lrhorer, the number of televisions eligibile to be adapted to TA-compliance will be small--probably only a few of the high-end models from two or three manufacturers in '06 and '07--certainly no more than ten distinct models altogether and probably fewer. One wonders if those manufacturers would bother--Mitsubishi is progressive enough that they might. I don't know about the others. For those few customers actually using the CableCARD slots in their televisions, it would be a great boon, cementing customer loyalty.
     
  17. shabby46

    shabby46 New Member

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    Aug 3, 2008
    Falls...
    You are right that I dont understand SDV too well, Im not a big communications guy, but I guess what I am asking is why is that that with my cablecards, the company can still send me premium channels like HBO, but they cant somehow make a note to send the rest of the channels my way?
     
  18. mikeyts

    mikeyts Stream Warrior

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    The backbone of the most modern cable systems is fiber, with coax running into your neighborhood, which can't transport nearly as much information as the fiber backbone can. It's a bit like a river with little garden hoses siphoning from it, bringing the content past homes. (Not a very good analogy, but I'll stretch it :D). Pre-switched-broadcast, all of the all-the-time channels were taken out of the river and put in your garden hose, but now they want to make more stuff available to subscribers than will fit in the hose at once. With switched broadcast, they pick and choose only the things that the homes attached to your local hose are actually using and put them in the hose; they can't send you anything that isn't also presented to everyone else using the same stretch of hose. (Yeah, it's a pretty poor analogy all right :rolleyes:).

    In practice, they continue to send some things to eveyone all the time, but some other things become only available upon request, sharing a designated portion of each "hose's" capacity.

    Take a good look at that illustration in the top post of this thread--in it, the big thick tube with the little houses on it represents my garden hose whereas the dashed yellow lines are the river.
     
  19. CharlesH

    CharlesH Member

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    Aug 29, 2002
    Sacramento...
    Maybe I am just missing it, but do the alternative TA implementations being discussed here require that the user get their Internet service from the cable company?

    There is the question of how TiVo talks to the TA: over USB vs over the home LAN connection (wired, wireless, whatever) to a centralized place on the home network.

    And the question of the upstream communication to the cable company SDV equipment: IP (over the public Internet vs over the cable) vs low level DOCSYS protocol on the cable.
     
  20. lrhorer

    lrhorer Active Member

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    They don't "send you" anything, other than the encryption keys for the premium services you are authorized to receive, and they only do that once every few days or weeks. Linear services are there all the time, period. It's just that if you do not pay for them, your box is not given the encryption key so it can decrypt the data stream which appears at every house in the city. Any linear channel eats up its respective timeslot on the entire CATV plant.

    An SDV stream is different. It does not appear at every house in the city. Instead, it appears at every house serviced by the fiber node of the subscriber who orders the stream. Typically this may be 400 - 1000 homes, or perhaps up to 3000 receivers. The stream in question then eats up the timeslot only on the node servicing the sub who requested it. The same timelsot on the other 100 - 500 or so nodes in the city is fee to carry some other video, or in fact up to the number of different videos as there are nodes. In an all digital CATV system (there are none of these yet) a typical plant may be able to handle about 600 QAMs, for a round figure. If all 600 are carrying 2 HD channels and one SD, that's 1200 HD channels and 600 SD. In a linear configuration, that's the limit. In a complete SDV configuaration, however, hypothetically a 500 node system with 600 QAMs could carry 600,000 HD videos and 300,000 SD videos. That's a big difference.

    The "always on" configuration you are suggesting is a linear channel. In a 500 node CATV system, a single linear channel reduces the total number of available channels by 500. A single analog channel reduces the total number of videos by 1000 HD channels and 500 SD channels.

    Note, however, that some channels, notably the National networks, the more popular "superstations" (WGN Chicago, TBS Atlanta, etc),, and the primary pay channel feeds (HBO, Showtime, Cinemax, TMC, Starz, etc) all have large enough market shares that those channels will be continuously viewed by at least one subscriber on every node. This being the case, SDV offers no significant advantage for the CATV provider over a linear implementation, so it is very likely that for the moderately long term future those channels will continue to be broadcast on linear QAMs. Any channel whose viewership during any significant period of the day is low enough so that at least one node on average will not be carrying the channel during that time represents a potential increase in the number of available channels if the provider switches them to SDV. In a system with 100 active receivers per node at that time of day, that means if during any period of the day a particular channel (including HD versions of popular channels) drops regularly below 1%, moving that channel to SDV will increase the humber of available channels, particularly VOD offereings. Since 99.9% of the viewing penetration is taken up by the 5 national networks, SD versions of the "superstations", and SD versions of the primary premium channels, plus a small handul of Cable Channels (Lifetime, Animal Planet, Discovery, etc), the remaining channels all represent lucrative conversions to SDV, or revenue left on the table if the provider does not convert. On the other side of the equation is the capital costs of conversion and the annoyance of subs who can no longer receive the channel.
     

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