In fact, high definition video has been around for a number of years. In America, you can buy high definition televisions, and watch high definition video content on all the major networks. Broadcasters are now buying HD equipment, because they know that TV channels are demanding high definition content. Meanwhile, for consumers, and anyone else who wants to use HD but can't afford the tens of thousands of dollars it costs for a professional camcorder, there's HDV.
The expression "HDV" is, fairly obviously, a combination of "HD" and "DV"; and that's exactly what HDV itself is: high definition video on a DV tape.
HDV uses MPEG-2 compression to achieve this feat - pure genius on the part of the manufacturers because they've managed to introduce an important new video format without all the effort and expense of having to design a new type of tape and the mechanical stuff to go with it.
HDV is a fantastic new format. But, to understand exactly how good it is, you need to understand quite a lot about high definition television itself. HDV is, in itself, just a way to achieve high definition television. HD video isn't just a bit better; it's a lot better than standard SD.
Remember: the resolution of standard definition television in the US is 720 by 480 pixels. The highest HD resolution is an incredible 1920 by 1080 pixels. That's over two megapixels, which means that it's well into the sort of quality you can get from digital still cameras. Of course it's nowhere near the tens of megapixels you can get from high-end digital still cameras, but don't forget that you get thirty of these pictures per second. So the overall effect is simply stunning.
To understand the way HDV works, we need to talk first about data rates. When you first come across digital video, it's difficult to see exactly how numbers can represent pictures – still less the ones and zeros that computers deal with. There's no need to go into too much detail here; suffice to say that when an image is digitized it's as if a regular grid is placed over the picture, and the color found in each "cell" of the grid is allocated a number that records its properties of lightness and color. It's these numbers that make up the data representing the video itself.
Now it's not hard to see that for moving video this is going to add up to a lot of data.
Next Section > Data, Compression and Codecs
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