Progressive Leaves Interlaced in the Past.

Interlaced footage was used in the early days of television to accomodate transmitter bandwidth limits. Today's technology is making progressive images easier to handle.

In the beginning... Progressive and interlaced video were actually developed in the 1930s. Progressive video is easy to visualize when comparing it to the medium which started it all, film. A film camera for the motion picture industry essentially takes 24 still pictures every second. When projected back at 24 frames per second, our brain doesn't notice each individual frame, and instead we see a single action filled image on the screen. The original technology used to broadcast television in the 1930s, however, restricted the bandwidth, or amount of information, that could be transmitted. Interlaced video was developed for these restrictions. For interlaced transmission the visual frame is divided into alternating scan lines, an "odd field" consisting of all the odd numbered scan lines, and an "even field" consisting of all the even scan lines." In the image above, a single "field" is represented for the interlaced example. Now, imagine the difference between throwing baseballs and bricks. Because baseballs are smaller, lighter and easier to throw, you could potentially throw many more baseballs than bricks. Original broadcast technology found it easier to "throw" twice as many interlaced fields as progressive frames. With the new era of HD technology and LCD monitors upon us, we can begin to throw those bricks much easier and faster than ever before!

To demonstrate the real-world differences between interlaced and progressive, two tests were shot similar to the one shown above; one using 1080i/60 (60 fields, interlaced to appear as 30 frames), the other at 720p/24 (24 progressive frames). DISCLAIMER: The process of optomizing the video for the web does not lend itself to showing drastic differences between the two settings, but the still images below absolutely do.

The above image is a screen grab of footage shot at 1080i (i=Interlaced). In this case, the camera is following a moving object. Notice the Interlaced fields that appear as alternating scan lines.

The above image is a screen grab of footage shot at 720p (p=Progressive). Also in this case, the camera is following a moving object. Like in still photography, the full frame is represented.

For more regarding; What to expect...The solution...The advantages of shooting progressive Click here for more details and a more in-depth look at progressive vs. interlaced shooting.