Times can be specified in h:m:s. To be more accurate you can use the form h:m:s+frame. Frame number is calculated the in SMPTE drop frame style. It will drop 2 frames every minute execpt every 10 minutes to compensate for ntsc's 29.97 mhz clock. The difference between real SMTPE and what I use is instead of being specified using h:m:s:frame it's h:m:s+frame. This lets you leave the +frame off and have the machine still understand what you are saying. You can also use decimal seconds (h:m:s.s) to specify within a second instead of exact frame numbers. (i.e. 0.5 would be frame 15, 0.9 would be frame 27 etc.).