Definitions – Frame Rate

As you probably know, the speed with which 35 mm movie film passes through the camera’s gate is measured in Frames Per Second. With film, this is a literal measurement. Every properly calibrated movie camera and projector moves the film at precisely this speed, and any movie can be played on any projector – as long as the equipment is in good working order, the movie should look just as the director intended.

With video, it’s a little more complicated. There are no real “frames,” so measurements in “frames per second” is a convention, not a literal fact. Instead, pixels are “drawn” on the screen in horizontal lines at a very high rate. A “frame” is usually understood to mean a full screen’s worth of data. TV screens, computer monitors, flat panel displays, and HDTV all use different methods to illuminate the pixels, and they may have varying frame rates.

For professional television, the standard is 30 Frames Per Second. For a Quicktime video, the frame rate might be 15 Frames Per Second.

Who cares? And why should you, as an eBay seller, care?

Frame rate will directly determine how smoothly your video plays. A high frame rate produces a high quality, easy to watch, professional looking video. But it also produces a large file. Compression applied to compensate for file size can mean degraded color or dropped frames, leaving you with a You Tube video that looks nothing like your original production.

Think of silent movies, which were shot at a lower frame rate than later sound films. When a silent movie is played back on a sound projector, with no adjustment to the frames per second, the movie seems to be in fast motion, giving everything a slightly ridiculous look. On the other hand, if the frame rate is too low, the film seems to move like molasses, with jerky and choppy motion.

To further add to the problem, video on the internet is dependent on the bandwidth of both the broadcasting and the receiving computer. If the connection speed cannot keep up with the video traffic, the video may stop and start repeatedly while traffic catches up with content.

So it is very important to choose a frame rate for your video that will

1) Keep your content flowing smoothly within the video and
2) Keep your data flowing evenly across the internet

On You Tube, this is usually between 15 frames per second (for a low motion video, such as a screencast) and 30 frames per second (for a full motion AVI)