iLife Creations

640 x 480 and the 40-pixel buffer principle

The finished works of many iMovie users are destined only for viewings on the small screens of our computers or our televisions.

When it comes to creating graphic images for those movies (for example: background images over which titles will play, or matte images for logos or bluescreen effects) you'll get the best results when using the proper dimensions for the small screen format and by employing the 40-pixel buffer principle.

While NTSC and PAL formats require a screen size of 720x480 and 720x576 respectively, iMovie files destined for QuickTime, iDVD or tape playback require a screen dimension of 640 pixels wide x 480 pixels deep.

Because televisions have the tendency to "cut off" the outer pixels of your movie, images or graphic elements within approximately 40 pixels of the edge of your iMovie screen may not be visible when viewed on a television. Therefore, make sure to make the graphic images used in iMovie are "television safe."

This can easily be accomplished by pulling in from the edges of your 640 x 480 full screen size a full 40 pixels from both width and height. This makes your effective "live image" area the center 600 x 440 pixels of the full-screen size. If you want the entirety of an image or graphic element visible to the viewer (for example: a logo or a title) make sure it exists within the 600 x 440 border.

posted by Erik @ 8:11 AM