VAD (Video After Demand) instead of VoD


In an earlier blog post I attempted to distinguish TVoIP (TV over internet) with IPTV, a buzzword for cable/telco live video offerings. My goal was to explain that we can be very happy with TV, movies and video that come to us over the internet after some delay.

The two terms aren't really very explanatory, so now I suggested VAD, for Video-after-demand. Tivo and Netflix have taught us that people are quite satisifed if they pick their viewing choices in advance, and then later -- sometimes weeks or months later -- get the chance to view them. The key is that when they sit down to watch something, they have a nice selection of choices they actually want to see.

The video on demand dream is to give you complete live access to all the video in the world that's available. Click it and watch it now. It's a great dream, but it's an expensive one. It needs fast links with dedicated bandwidth. If your movie viewing is using 4 of your 6 megabits, somebody else in the house can't use those megabits for web surfing or other interactive needs.

With VaD you don't need much in your link. In fact, you can download shows that you don't have the ability to watch live at all, or get them at higher quality. You just have to wait. Not staring at a download bar, of course, nobody likes that, but wait until a later watching session, just as you do when you pick programs to record on a PVR like the Tivo.

I said these things before, but the VaD vision is remarkably satisfying and costs vastly less, both to the consumer, and those building out the networks. It can be combined with IP multicasting (someday) to even be tremendously efficient. (Multicasting can be used for streaming but if packets are lost you have only a limited time to recover them based on how big your buffer is.)


TiVo has the notion of a Season Pass, where you just tell it you’re interested in a show and the TiVo will grab it for you when it’s available. It’s sufficiently flexible that you can ask for all new episodes, or just to keep at most one copy of the latest airing (which is what I do with BBC News). One VAD service I’d like would be a season pass to an episodic show you want to watch from the start: you tell your PVR about it, and it downloads the first show, whether it be the classic black-and-white Addams Family or that new series your friends are raving about that isn’t in reruns yet. That can hover on your PVR for however long it takes you to get to it; as soon as you finish watching the first episode and delete it, it downloads another one. You could easily go through one episode a day this way without requiring unreasonable amounts of bandwidth. If the show is currently running, a really smart such season pass would automatically cut over to new episodes as soon as you catch up, and could go back and download the most recent episode if your cable provider had a problem and the show didn’t record.

You could even have a variety of pricing models for such a service: you could get it for free with targeted ads inserted in the commercial breaks, or make it profitable for the hosting company to send it to you ad-free.

We used to have a friend who taped just about everything he watched or intended to. He was always willing to share his collection. If we didn't get a show in our area or we missed an episode, he'd just pop a VHS tape or two in the mail for us. It was great! Physical mail might have a wretched latency, but it has great bandwidth.

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