Key Frames Key frames are complete frames of video, containing all the information needed to view the frame. The frames between key frames are called difference or delta frames, and only contain information that has changed since the previous frame. When no key frames are specified, Premiere applies only spatial compression. There are natural key frames and forced key frames. In Premiere, natural key frames are defined for edits and markers.
Premiere adds forced key frames according to the specified key frame rate.
QuickTime may also create a forced key frame when it detects a 90 percent or greater difference between the current frame and the previous frame. When mastering your movie to CD-ROM, you can use the Movie Analysis and Data Rate Analyzer tools to analyze your finished clips and help you choose the right compression method for your distribution and playback needs. You can also use the CD-ROM Movie Maker to optimize your audio and video blocks for the best possible playback from the media you will be using. Video Video, the most popular scheme used by systems not employing hardware compression, is an image compression method developed by Apple to permit fast compression and decompression while maintaining good picture quality. Use Video for live video images.