Compression ratios impact image quality. Use lower compression ratios to produce smaller file sizes of lesser image quality. The compression ratios vary, depending on the compression program you use.
When creating animations with many moving parts or parts that move quickly, the key frame rate impacts image quality. The key frame rate specifies how often a frame saves an exact copy of the screen display. All other frames include only changes you make since the previous key frame. If you have excess variation between frames, lower the key rate.
To compress a video after clicking Save in the Save Animation to File dialog box: