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SDV FAQ

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

  1. Nov 16, 2007 #621 of 2401
    mrmike

    mrmike Custom User Title

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    Yeah, that's where the $100K came in. And with the spec being under private control by an entity with no interest in making things easier for me, what guarantee do I have that the spec won't change every 6 months? Or that "misbehaviours" would be well explained and investigated. Open specs run the world for very good reasons.
     
  2. Nov 16, 2007 #622 of 2401
    ah30k

    ah30k Active Member

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    There are no guarantees the spec won't change but if it does change then Motorola, BigBand, Arris, SA and every other SDV vendor will be impacted as well causing expensive updates to fielded headends. All of these impacted vendors will put pressure on the spec owners to settle them. Open specs don't come out of the heavens on beams of sunlight. There are very heated battles over whose preferences are chosen. Eventually SDV might get there.

    By the way, you mention "me" and "I" in your responses. Are you developing to this spec or just an observer with a interest in them.
     
  3. Nov 16, 2007 #623 of 2401
    lrhorer

    lrhorer Active Member

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    Well, it's far from the whole point, but that is one benefit of OCAP, yes. By employing middleware, the basic sockets on the end terminal remain unchanged while new featuires are added to the system as a whole. In this scenario, TiVo can make just as much use of the stability of the OCAP interface on the receiver side as the CATV company's STBs. Barring a middleware solution like OCAP, however, the answer to the dilemma for the CATV company is backwards compatibility. Either way, the TiVo is very likely to be shielded by the same armor which covers the CATV company's assets.

    If any CATV provider is using OCAP, then there is nothing preventing Tivo from supporting OCAP. It's proprietary protocols which throw a monkey wrench into the machinery, but a proprietary protocol is as I said going to tend to be loaded with backwards compatibility.

    Up to here your point is well taken.

    I would say this doesn't follow. A dongle is no less prone to obsolescence than the TiVo iteslf, and if the dongle is provided by the CATV company, then the CATV company is going to be responsible for keeping the dongle up to date. This means they a re either going to have to freeze their protocols (at least those availble to the dongle) or change out thousands of them nationwiode every time they change their protocols.
     
  4. Nov 17, 2007 #624 of 2401
    jercra

    jercra New Member

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    This is right on. There are lots of vendors involved in the many aspects of SDV (SM, ERM, Client, etc) and all of them must conform to the specs currently implemented. Add in that HE techs, support orgs and engineering orgs need a consistent set of behaviors and error codes and you can pretty quickly see that there will be no rapid spec changes. It aslo bears noting that companies like Comcast and TWC do not go blindly into the future. The roadmap for SDV functionality is pretty much laid out for the next couple of years. There won't be many surprises for any SDV vendor and that would include TiVo.

    Beyond any of this is the fact that Comcast and TWC are actually actively working towards a common spec, not just for SDV but for all interactive services. Once this is accomplished (and yes it will happen at the speed of cable companies) every other cable company will fall in line behind them as every single vendor will cater to those two companies. They are not doing this because the FCC mandated it. They are doing it because it is the best thing for them as it allows all vendors to develop more rapidly and more economically.

    In the mean time, it's not out of the realm of possibility for TiVo to partner with another company that is very familiar with all of the various SDV specs to build a TiVo server that resides in the HE and does all of the required protocol translations for each SDV spec. This would allow TiVo to develop a single client without worrying very much about adapting every TiVo whenever a spec did actually change. This is exactly the approach that Digeo took with their Moxi STB to enable VOD.
     
  5. Nov 17, 2007 #625 of 2401
    morac

    morac Cat God

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    Comcast picked Motorola to supply the hardware for SDV and BigBand to supply the software to handle communication between the headend and the set-top box at the end of last month. BigBand also supplies the software for Cablevision, Time Warner Cable and Cox Communications.

    Since they were running trials in Denver, CO and Cherry Hill, NJ, and the Cherry Hill, NJ system uses Scientific Atlanta hardware, it looks like they liked the Motorola ones better (I'm guessing Denver uses Moto).

    Since SA and Moto systems are not compatible (which is why you can't use a Moto cableCARD is a SA cable system and vice-versa) I'm not sure what this means for SDV in SA areas.
     
  6. Nov 20, 2007 #626 of 2401
    moyekj

    moyekj Well-Known Member

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    Mission...
    SDV is coming to Cox, Orange County, which means:
    * 6 HD channels I already can't get (CNN HD, Discovery HD, NFL Network HD, TLC HD, History HD, Animal Planet HD)
    * 4 HD channels to be launched county wide on Dec 17 I won't get (Food HD, HGTV HD, HDNet, HDNet Movies)
    * Any SD and HD channels added from here on out I won't get
    * Digital simulcast channels (for channels below 100) will be going away: CableCard customers will revert back to analog channels in channel map
    NOTE: SDV hasn't even been deployed yet, but this is all in preparation for SDV deployment.

    This also brings up an interesting point: Let's assume for a moment the tuning resolver was already available. Being a CableCard customer my lineup would still be compromised based on anticipation of SDV rollout. Those CableCard customers with tuning resolver would need special treatment for their account to make sure the channel map of regular digital cable box customers would be used instead of the normal CableCard channel map since obviously they can be (and in my case are) different.
     
  7. Nov 20, 2007 #627 of 2401
    AZrob

    AZrob Member

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    This is the first I have heard that implementation of SDV may result in below-100 channels going back to analog. Is this an expected consequence of SDV's implementation or is this just a choice local to Cox Orange County?

    Rob from AZ
     
  8. Nov 20, 2007 #628 of 2401
    moyekj

    moyekj Well-Known Member

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    Mission...
    It's an Orange County choice. Though of course I don't like the consequences, it kind of makes sense seeing as something like 50% of Cox customers are analog only and there are also digital subscribers tuning to analog channels without a digital set top box. Still I think Cox OC is being overly aggressive seeing as they just upgraded to 860MHz locally which would have been enough bandwidth to accommodate these recent additions without SDV - but I suppose they are making room for future growth...
     
  9. Nov 20, 2007 #629 of 2401
    AZrob

    AZrob Member

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    Actually, I kind of like this approach, as long as it's temporary. My wife was very disappointed to hear that moving to CC's from a STB ended up reducing the number of hours available on my Tivo HD + Expander disk from 800 to 400. She was unmoved by the fact that digitally simulcast channels have much better PQ. She wanted to able to record whatever she wanted whenever she wanted. So, if we could access the analog channels again (in analog) that would be a good thing...for her. I see it as a way to get along until the 2 or 3 TB Expander disk is available.

    Someone could write a book on "diskspace wars" between spouses....

    Rob
     
  10. Nov 20, 2007 #630 of 2401
    mrmike

    mrmike Custom User Title

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    I was. Licensing and development costs killed the project I was working on. Hence my slight bitterness about the subject.
     
  11. Nov 20, 2007 #631 of 2401
    morac

    morac Cat God

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    Actually, unless you record everything at basic or medium quality, recording digital channels should save you disk space. In my system digital channels recordings are definitely smaller than "best" analog, usually smaller than "high", sometimes smaller than "medium" and never smaller than "low". Your cable company may not compress the signal as well though.
     
  12. Nov 21, 2007 #632 of 2401
    AZrob

    AZrob Member

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    See, but that's the problem...normally we did record everything at Basic when we had analog, because then we could get 300 hours from my Humax S2. Adding the DVR Expander to my new Tivo HD, I calculated I would get the equivalent of 800 hours. But actually, it's more like 400. Digital channels take up twice as much as Basic.

    Rob
     
  13. Nov 21, 2007 #633 of 2401
    sfhub

    sfhub Active Member

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    They aren't compatible from an encryption standpoint but does that mean they are completely incompatible in all aspects or could some conversion layer handle mapping SDV high-level functionality to hardware specific function?
     
  14. Nov 21, 2007 #634 of 2401
    mel.simmons

    mel.simmons New Member

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    I'd like to understand a bit more about the technical challenge of the "tuning resolver". The first message in this thread gives a nice high-level overview. But how much is known about the details of the protocol? Has anyone with SDV on their cable service tried to "snoop" the communications going back and forth from their set-top box? Would this protocol be largely the same on all of the cable systems adopting SDV, or are there major incompatibilities between cable systems? Should we be expecting one, universal device coming from TiVo? Or might we see some cable companies offering solutions while other companies do not?
     
  15. Nov 21, 2007 #635 of 2401
    classicsat

    classicsat Astute User

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    The technical challenge is mostly matching the low level protocols and formats the headend expects, and to a certain degree security.
     
  16. Nov 21, 2007 #636 of 2401
    jercra

    jercra New Member

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    AS has been stated, there are basically 2 different protocols to which TiVo would need to adapt. The TWC Protocol (SA) and the Comcast NGOD (Moto) protocol. There are basically three points of integration to get SDV working on any CE device, not just TiVo.
    The first is the ability to read a dynamic channel map off of the cable plant. The plans for SDV include the ability to rapidly and frequently change which channels are broadcast and which are switched. This is typiclly done by reading either an IB or OOB carousel. This is very different between an SA and a Moto plant.
    The second is generating a client that can speak "SDV", so to speak. It will need to be able to self-discover a service group, set up a session and tune to the returned freq+program number. Self-Discovery is typically done by reading TSIDs off of the IB. The session setup protocol is very different between the TWC solution and the Comcast solution.
    The third is the actual ability for 2 way communication. This is the problem that the dongle is proposed to solve.

    So, even if they do get the tuning resolver done there will still be a software development effort and then an even more complicated deployment strategy as each TiVo will need to know what type of SDV protocol to implement and be able to implement them all.
     
  17. Nov 21, 2007 #637 of 2401
    mikeyts

    mikeyts Stream Warrior

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    I'd imagined that the dongle would be like CableCARDs, an adapter to the proprietary protocols on the wire for the TiVo. Any proprietary protocols would be encapsulated in the dongle (which is why'd they'd have to come from the cable providers) and the TiVo would speak a new "dongle protocol" to it to request channel mappings and to receive SDV-related requests from the system. I considered the possibility of the dongle being a primitive tranceiver to implement the physical layer on whatever OOB frequencies are being used for SDV, with TiVo implementing everything else internally, but that'd require that every proprietary SDV protocol be licensed to TiVo. Messy.
     
  18. Nov 21, 2007 #638 of 2401
    classicsat

    classicsat Astute User

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    Being the resolver will likely be used on boxes other than TiVos, it behooves the cable provider to make the Dongle as smart as possible.
     
  19. Nov 21, 2007 #639 of 2401
    XBR

    XBR New Member

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    Sounds like the Carterphone Decision all over again...sigh.
     
  20. Nov 23, 2007 #640 of 2401
    pmiranda

    pmiranda New Member

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    On the contrary, that seems to be the most elegant, compact, and extensible solution to me. All the protocol is handled in software that TiVo can integrate into existing code and it can be upgraded through existing infrastructure. The dongle is just a dumb piece of cheap hardware that could be (but probably won't be) given away because it has practically no inherent value. This would allow the most flexible path for future upgrades beyond just SDV to allowing other two-way applications, even an OCAP capability if necessary.
     

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