Network DVR vs. Remote-Storage DVR

Glen Hardin of Time Warner Cable recently wrote a comprehensive (and fabulous) article for Cable360 on the 2008 ruling in favor of Cablevision’s right to offer network-based DVR services. In it he uses the more precise term Remote-Storage DVR (RS-DVR) rather than Network DVR (nDVR) to describe the technology Cablevision has proposed. Is the difference in jargon critical? Actually, yes. Even if you have very little interest in the technical details, there are practical ramifications to the fact that Cablevision may one day soon launch RS-DVR rather than true nDVR services.

Very briefly, nDVR refers to a service where a program can be recorded and stored in the cable network and then accessed by any subscriber. In contrast, RS-DVR refers to a service where any subscriber can record a show and store it on the cable network, but that stored programming is only available to the person who recorded it. For legal reasons, even if two people want to record the same show, it has be recorded twice, and each recording discretely stored.

RS-DVR is legally pragmatic, but technically it represents a series of trade-offs. Instead of set-tops that need loads of storage space, you end up with mammoth amounts of space needed on the network. Discrete storage of each recording also means that there’s no way to cache content for more efficient delivery of popular programming. And finally, the fact that each recording requires its own video ingest means that video servers need significantly more ingest capacity than they currently have.

There’s a lot of potential in network-based DVR services, even the somewhat hamstrung approach of RS-DVR. (More storage options, everything on-demand, new interface options for management of recordings) However, the technical burdens mean that RS-DVR won’t necessarily provide subscriber cost savings early on as some might expect. Also, I have to wonder at how smoothly RS-DVR can be implemented in the short term given the new technical requirements. I expect there will be kinks even once the service finally becomes available from a service provider near you.

13 thoughts on “Network DVR vs. Remote-Storage DVR”

  1. It’s possibly a better way to do whole-home DVR. Wish TiVo had little extenders instead of having to buy a full-fledged unit to share view in other rooms. (Also wish the transfer speeds were quicker.)

  2. First off, great discussion of the difference between nDVR and RS-DVR. Never really thought about the difference, now I feel a little better informed.

    Second, I too want TiVo to come out with a media extender. Transfer speeds are fine for me (I have GigE wired to all my TV/Tivo locations – even if the Tivo can’t use it yet), but I really want an ability to pull recorded content from my 3 Tivos (two HD and one S3) down to a smaller TV in my office without the expense of a full Tivo unit. I Don’t want to record or store anything there, I just want to be able to access my already recorded content!

  3. Good point on whole-home DVR, and Hardin does touch on that in his article. Particularly interesting when you think about “trusted devices” extending beyond set-tops and beyond the home. i.e. Download a copy of the show you recorded to your phone before your next flight and watch it in the air.

  4. I never really gave this much thought, but with my son now 2 yrs old I never know what tv won’t have Noggin on that I can watch. I currently have cablevision so I either have to record the same shows on both dvrs (which can be a waste and on heavier tv viewing days is not possible) or plan my tv watching around when I think a specific DVR will be free. This has led me down the road of the server/media extender environment so I don’t feel tied down to a dvr. Whatever the final solution is for Cablevision (whether it be nDVR/RS-DVR/whole-home DVR) it will be a much better solution then what they currently offer.

  5. Good explanation of the differences but I’ll stick with my Media Center, thanks. No matter which solution a cable company would go with there’s one thing to consider: What do you watch when the cable is out? Now, if my service drops, I have full access to all of my recordings. With something like this (which to be honest I didn’t know cable companies were looking at) when service drops you don’t even have that to fall back on.

    No thanks.

  6. I’d love for Roku to be an “extender” for TiVo. The “TiVo Channel”.

    I avoid cable company products and services at all costs. Every time I try something new, inevitably, the bill comes with more costs than was supposed to. My wife detests the thought of a skanky cable guy in our house.

  7. “…Remote-Storage DVR (RS-DVR) rather than Network DVR (nDVR) to describe the technology Cablevision has proposed…Cablevision may one day soon launch RS-DVR rather than true nDVR…or network-based DVR services (NB-DVRS)…”

    “…MB CD-R – a DVD-R has 6.4 times the capacity of a CD-R. Pioneer has also developed an 8.54 GB dual layer version, DVD-R DL…Data on a DVD-R cannot be changed, whereas a DVD-RW (DVD-rewritable) can be rewritten multiple (1000+) times. DVD-R(W) is one of three competing industry standard DVD recordable formats; the others are DVD+R(W) and DVD-RAM…”


  8. If Cablevision could have built an nDVR and got away with it, of course they would have. But they wanted to increase their chances of winning the expected lawsuit, so they made it as much like a DVR in the user’s house as possible, which meant that each user has to have their own copy.

    I assume that once the issue is resolved by the Supreme Court, assuming the result is in Cablevision’s favor, the media companies & Cablevision will work something out. And once they do that, a more normal implementation with only one copy of each program recorded, regardless of how many people ask for it, could be coming. We’ll just have to wait and see.

    Mari, since RS-DVR is built by one of your competitors (e.g. Cisco) can we really assume your commentary here is unbiased?

  9. It’s always reasonable to assume that I have some bias given that I work for Motorola. But in this case, Motorola also has RS-DVR technology. Frankly I’m just interested in how the video networks are going to end up being re-architected. It fascinates me how Internet and cable delivery are looking more and more similar, even when we’re not talking about IP packets.

  10. could they just have people sign a form saying they want to record everything :) That way they work to scale the back end to a reasonable level and the person gets on demand for whatever period of time the content provider allows. That would truly work for 50% or more of most TV viewers.

    As for TiVo – I currently record mainly SD analog so I can easily pass shows around to the 3 TVs we have in the house and the kids get to pick what records on the SD H400 in the bonus room. I like the idea of extenders and would love if TiVo added standard protocols so that things like Roku could pick them up – but can they play the TiVo format directly and do decryption – cause if not then transfer to a Roku or whatever becomes like a TiVoToGo transfer and slows way down. Not good for an extender. This is before the business problems of the fact they sell less multi subscriptions to a house and how many new subs do they pick up because of the new feature?

  11. Fanfoot, beyond Mari’s bias disclaimer I’ll add one of the cool things about the way she blogs here AND on Motorola’s site is her interest in and commentary on the broader industry beyond solely Moto products and marketing. She loves this stuff.

    And you frequently do a pretty good job keeping a neutral perspective, as well. :) (Work is a four letter word.)

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