I know that sounds trite but it probably is as simple as that
I can think of good reasons to be able to easily know if it's drop or non drop.
Using ":" and ";" to denote one or the other is very simple on the eye and probably quite easy on the old hardware that first had to cope with this.
1:23:45;06 and 1:23:45:06 may look the same at first glance, but since one uses drop frame and the other doesn't, they actually differ by about 5 seconds. That's a critical time difference when a network is trying to sync a broadcast.
Changing the : to ; is a visual cue as to which timecode is being used.
How odd. Without the first line of "test" at the top, this post gets blocked. With it there, it goes through successfully.
Hmmmm. I don't think i said that well. Chronologically by the clock the two timecodes are the same, but the position in the file differs by 5 seconds' worth of frames.
That was more than I ever wanted to know about SMPTE.
Some of you guys are obscure . . . but relevant. :-)
wrote on 2/4/2012, 9:10 AM
Working in the linear tape world of editing most of my career, the semi-colon was a visual indication of the drop code vs. non-drop. When doing spot editing, we normally edited with non-drop tc. Made the math a lot easier and you could start spots at 1 minute even. When doing program length, we normally used drop.
Early edit/machine controllers could not always determine the drop frame status and you would have to set the status manually. This visual indiction was important.
Dunno if this is relevant, but CMX 3600 EDL format originally used a data field specifying drop or non-drop TC and all TC entries used colons. When Grass Valley introduced their EDL format, it did away with the TC data field and began using colons and semicolons to differentiate drop from non.
wrote on 2/4/2012, 11:22 AM
I never used CMX but you might be right. Grass Valley came on pretty strong in the earlier machine control/switcher days. I started on Datatron and then our proprietary controller.