[bbaillie]

What is the overall purpose of the FINE button when editing video (Cutting out Commercials)
I think this maybe this is the crucial tool in the editing process. Give an example
if possible.

[tsantee]

Clicking the Fine box shows more places where an edit can be marked. MPEG-encoded video formats are compressed video. The compression is in the form of removing data in most frames where the lost data is compensated for by referring to similar data in adjacent frames. Occasionally (such as every 15 frames) there is a key frame that has all the data. You want to edit on key frames and not on the others. That's why you can't make frame-accurate edits of MPEG encoded video without special software that uncompresses the group of pictures between the key frames.

My presumption is the Fine setting shows every key frame whereas fewer key frames are shown when Fine is unchecked.