premiere pro cs6
You can set a marker on clips in the Source, Timeline or Program panes to help you do more precise video and audio editing.
The marker creates a snap-point on a clip or the Timeline that the playhead will lock onto.
This can be helpful when you're editing audio and you want a video track to begin exactly at the downbeat of a song. You can set a marker during audio editing at the downbeat so you then can position a video clip to begin at precisely that point.
You create a marker in a clip in the Source, Timeline or Sequence panes by moving the playhead to the desired point on the clip and pressing the M Key. The marker will appear as a tiny green icon just above the playhead.
To delete a marker right click on it and select Clear Current Marker in the drop-down menu.