What does interlaced image capturing mean, and what does it have to do with digital video?

What does interlaced image capturing mean, and what does it have to do with digital video?

Well, to answer the above question, digital video cameras come in two different image capture formats: interlaced and progressive scan. So, what it has to do with digital video is that it is a format it uses, but for what it is, we need to take closer look. Let's take a look at what interlaced image capturing really is:

What does interlaced image capturing mean?
What is means to capture an image using an interlaced camera is that the camera will record the image in alternating sets of lines. So, it means that the odd-numbered lines are scanned, after which the even-numbered lines are scanned, then the odd-numbered lines are scanned again, and on and on. So, it rotates, and scans in sets. These sets have names, one set is called field, and two fields of opposite parity paired is called a frame.

So what does it have to do with digital video? Well, interlacing is used by all of the analogue TV broadcast systems currently, and is simply one of the image capturing format options available in digital video. It is the original image capture format of digital video, and has been used for quite some time, especially at the professional level (not as much at the consumer level).

Most of what you see on the news, and other broadcasts are shot using an interlaced system. However, the majority of footage shot for home, and other use is progressive scan.

What are the benefits of interlacing?

One of the most important factors of interlaced digital video is bandwidth. This is measured in bit rate, and the greater the bandwidth, the more expensive the system gets. So the benefit of interlaced video when it comes to bandwidth is that it reduces the signal bandwidth by a factor of two, for a given line count and refresh rate. Meaning, you spend less using interlaced digital video.

Another benefit of this bandwidth is that with it you get twice the display refresh rates for a given line count (versus progressive scan digital video). So what does that mean? Well, a higher refresh rate reduces flicker on CRT monitors, so motion looks better because the position is updated more often.

Also, another benefit is that for a given bandwidth and refresh rate, interlaced video can have a higher spatial resolution than progressive scan. So, your resolution is often higher.

As you can see, there are several benefits, most of which have to do with the output of the video. If you view your digital video on an interlaced system, you will see motion better, you will have a slightly higher resolution, and you will get this for less.

However, this is not to say that interlaced is better than progressive scan. In fact, most believe that progressive scan, as a whole, is a better system, however, interlaced has its place, and plays a very important role in that place.

When determining what type of image capturing you want for your digital video recorder, consider your uses. If you will be filming a soccer game, having something that records motion better, and displays it better on the screen will be what you want.

Look at your options, compare prices, and determine what best fits in your budget, consider all the extras, including editing software, etc. and then determine which digital video image capturing format is best for you. They both have pros and cons.