The Basics of Frame Rate Conversion

The Basics of Frame Rate Conversion
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Converting frame rates is often necessary in today’s world where images are captured on much more than photographic film. What motion picture film basically does is catch sequential pictures on a roll of film with each image captured in a ‘frame.’ The rate at which these frames are taken or played back has been called frames per second or FPS. Even though very little filming is actually done on real film these days, the term continues to be used as the industry standard. Today, the different ways in which images are captured creates the need for frame rate conversion and improving frame rate.

What the Human Eye Sees

Although the human eye doesn’t see in FPS, there is a point at which the eye can perceive the movement of individual frames on a piece of film. If the film is played back too slowly, we see an image that appears jerky or flickers. The sound takes on lower tones and human ears have a hard time stringing them together into cohesive meaning. Alternately, if film is played back too fast, the eye cannot fully distinguish one image from another and they run together; the sound becomes high-pitched and hard to decipher.

Frame Rate Standards

Today, there are three frame rates that are considered standard in the industry: 24p, 25p, 30p (‘p’ being FPS). These three have been deemed the most useful in providing playback of images that are easy for the human eye and ear.

Even though little ‘film’ is actually made, the FPS for the playback of images is still done at standard rates. Television is the United States and Europe follow these same rates. When images are created using a different rate it is necessary to alter the rate and make the images viewable on a different device. In the case with television in the U.S. improving frame rate takes place to slow down the FPS from 24p to 23.976 FPS for broadcasting.

Special Effects and Animation

Many special effects and animation are done through video rendering. This is the process where an image is created using a computer. Video rendering is done one of two ways. The first is by using a model or actual object and then outlining the features that are used to create an animated figure. The other method, called real time rendering uses no model, and the image is created solely inside the computer. This type of animation must also be created using the standard FPS for viewing.

Converting Film for Viewing

There are dozens of software programs available on the Internet to help convert images from one frame rate to another. Nearly all will readily convert avi, divx, wmv, xvid, asf, mov, rm, quicktime, vcd, rmvb, dvd to mpeg, rmvb, vcd, dvd, asf, wmv, avi, xvid, Divx, mov, 3gp, iPod, Flash swf, mp3, Flash flv and wma.

So if you want to convert your family 35mm to DVD, or you want to put the funny video you just saw onto your iPhone, there is a program out there that can do the frame rate conversion for you.