Wednesday, February 21, 2007
You may be thinking that a Digital Video Recorder sounds a lot like a VCR. While there are many similarities in the function of the two, how each one executes its purpose is very different from the other and that makes a huge difference when it comes to how effective they are for their users.
While a Video Cassette Recorder records and analog television signal onto a video cassette tape, a Digital Video Recorder records a digital television signal onto a built in hard disk. When the signal first comes into the digital video recorder's box, it goes through a tuner and then is converted to MPEG-4, MPEG-2, or MPEG-1 data compression formats in order to be stored on the hard disk. Then, when you're ready to watch the recorded program, the Digital Video Recorder retrieves the program from the hard disk, decompresses it, and sends it to the television set. All of this is controlled by a computer motherboard that typically runs a heavily modified version of Linux. Of course this is a somewhat simplified description of how a Digital Video Recorder works, but it demonstrates the principle.
This entire process gives a Digital Video Recorder a number of advantages over the VCR that it- along with the DVD player- has made obsolete. The most obvious advantage is that you don't need video tapes in order to record with a Digital Video Recorder. The other advantage- one that's at least as valuable as not needing video tapes- is that because a Digital Video Recorder has many of the same components of a computer it can be programmed through an intuitive graphic user interface instead of the difficult to understand menus of a Video Cassette recorder.
There are two major disadvantages to a Digital Video Recorder. The most major one is that the vast majority of them require a subscription that allows you to download program listings from the manufacturer every few days. (Program listings are necessary when it comes to knowing what you want to record.) This is a small but ongoing cost for the entire time you own the machine. The other disadvantage is that, unlike a VCR where you can just buy more tapes, you can't add extra storage capability to a Digital Video Recorder.
That said, there is some newer technology that provides work arounds for both of those two problems. The first is a Digital Video Recorder that comes with access to program listings that are freely donated, so there's no ongoing cost of owning one of these units. As far as not being able to expand the storage capacity, some models have built in DVD burners that will allow you to burn programming from the hard drive of your Digital Video Recorder onto DVD's. That means that you can create your own DVD library and share DVD's with friends.
Digital Video Recording technology goes a long way towards putting control of video in the hands of viewers.