High Definition Recording

High definition recording is the new fad in camcorders. When you step into an electronics store, the sales people will always try to push it. From HDTV to HD camcorders. Everything is about high definition these days. But is it worth splurging on a HD camcorder? They don't come cheap. In fact, they are sold at a large premium over standard definition camcorders.

Standard definition camcorders record videos with a vertical resolution of 480 lines (NTSC) or 576 lines (PAL). HD camcorders, on the other hand, have a much higher vertical resolution of 720 lines or 1080 lines. As such, HD camcorders deliver 2X to 4.6X as many pixels in each frame as the best standard definition camcorder.The result? Sharper pictures with much greater detail. It's like switching from VCD to DVD.

That sounds great, doesn't it? Who doesn't want to capture their memories in the best video quality possible? However, high definition video is a young, evolving standard. What one company touts as Full HD may have a lower resolution than another company's plain HD. You have to filter out the thick marketing fluff on these HD camcorders to find the cold, hard facts. Let's take a look at some things you should check before you buy a HD camcorder.

720p Or 1080i?

Currently, the standard HDTV formats are 720p and 1080i. 720p is a progressive scan (hence, p) mode with a vertical resolution of 720 lines. That means all 720 lines are displayed in each frame. In contrast, 1080i is an interlaced mode with 1080 lines. That's 360 or 50% more lines than the 720p format, but they are displayed in an interlaced fashion.

That means only half the lines (540) are displayed in each frame. Instead of displaying all 1080 lines (as a progressive scan mode would do), the video frames alternate between odd and even lines. One frame will display only the odd lines, with the next frame displaying only the even lines, followed by another frame displaying only the odd lines, and so on. This allows the camcorder to deliver the high resolution at lower bandwidth.

As you can see from the comparison on the right, progressive scan is the preferred choice where video quality is concerned. Of the two standard HD formats, 720p would actually be preferable to 1080i, even though 1080i has 50% more lines.

However, most consumer camcorders only support the 1080i HD format because it's currently too expensive and too difficult to record in 1080p. 1080i is also easier to sell to the consumer because it is a "bigger" number than 720p. Like it or not, that's marketing logic.

So, what does this mean to us, the consumer? If you have a standard definition TV, then you need not worry. But HDTV sets based on LCD, DLP or plasma displays are progressive scanning by nature. These displays have to deinterlace the interlaced video or there will be visible motion artifacts during playback. Fortunately, progressive scan TV sets have integrated deinterlacing systems to properly display interlaced videos. However, deinterlacing reduces the image quality.

In short, the future lies in progressive scan formats like 720p and 1080p although logic dictates that camcorder companies will probably shift to progressive scan only when 1080p is easy and cheap enough to implement. Currently, only the new Canon HV20 camcorder is able to do 1080p, albeit at a low frame rate of 24 fps (NTSC) and 25 fps (PAL). If you are not in need of a camcorder now, it might be a good idea to wait for the new generation of 1080p camcorders. That may take another year or so though.

Do You Have Full HD?

The HD format is pretty loosely defined by the number of horizontal lines - 720 lines in 720p and 1080 lines in 1080i. But what about the number of pixels in each horizontal line? Most of us will probably never bother to ask since HD is HD, right? Those who actually wonder will be placated by claims of Full HD support.

First, let's be clear about what the standard HD resolutions are. 720p video should have a resolution of 1280x720 pixels. 1080i video, on the other hand, should have a resolution of 1920x1080 pixels. However, not all camcorders promising Full HD actually deliver those resolutions.

Sony, for example, is a noteworthy offender. Their entire range of Full HD camcorders only record 1440x1080 pixels - 25% fewer pixels. In contrast, competing HD camcorders like the Canon HV10, HV20 and the new JVC Everio GZ-HD7 support the full HD video resolution of 1920x1080.

Similarly, Panasonic's HDC-SD1 and HDC-DX1 HD camcorders also cannot capture the full 1920x1080 resolution. That capability will only be available in their recently announced HDC-SD3 and HDC-DX3 camcorders. Don't ask us what happened to SD2 and DX2. Panasonic skipped past those model numbers. To their credit though, they did not claim full HD support.

Therefore, you should never assume that all HD camcorders have full HD capabilities. You should also be wary of spurious claims of full HD support. Every company has a well-paid marketing department whose only job is to make a half-empty cup look full.