About compression keyframes

Compression keyframes are different from the keyframes that you use to control track or clip properties, such as audio volume or clip rotation. Compression keyframes are automatically placed during export at regular intervals in the movie. During compression, they are stored as complete frames. The frames between the keyframes, called intermediate frames, are compared to the previous frame and only the changed data is stored. This process can greatly reduce file size, depending on the spacing of the keyframes.

Choosing an optimal compression setting is a balancing act that varies depending on the type of video material, the target delivery format, and the intended audience. Fewer keyframes and more intermediate frames result in smaller file sizes but produce lower‑quality images and motion. More keyframes and fewer intermediate frames result in larger file sizes but produce higher-quality images and motion. Often, the optimal compression setting is arrived at through trial and error.