| Drop frame vs. non-drop frame
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 | Drop frame vs. non-drop frame
by Robert Dombaj on Aug 24, 2003 at 12:26:51 am |
Hello,
I recently started to edit for broadcast on an Avid MC 11 and came upon a few technical stumbling blocks. I'm hoping someone can explain/help.
The company I work for uses drop frame for input/output and I recently completed a project that starts contains several clips on the timeline. The first picture starts at 10;00;00;02 (because of drop frame). The clips are 1-2 minutes long and they are 10 seconds apart. Each clip starts at the 2 frame mark. So...for example, clip #5 starts at 10;05;45:02
Which leads me to my question...is this correct, should I start each clip at the even mark, as in 10;05;45:00
How does this whole business of drop-frame timecode relate to a timeline and how video is recorded onto tape?
Thanks in advance for any answers.
Robert D.
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• | | | |  | Re: Drop frame vs. non-drop frame
by Rich Rubasch on Aug 24, 2003 at 9:41:35 pm |
When you say "should I start the clip on the even mark" do you mean you have a non-drop sequence? On a DF encoded tape, every 2 minutes you will not have an even 00 minute mark. Here's why.
The magic number is 2 minutes. I prefer to edit spots in NDF and start at the 1:00:00:00 even mark. On "long form" projects, pretty much anything over 2 minutes, we stripe a DF tape and start at the nearest even number. If it was an 02 number, so be it.
DF is a way of counting frames so that as you count upward, it keeps time to actual time passed. Whereas with NDF it simply counts 30 frames for every second. Since video is palyed back and recorded at 29.97 frames per second, at some point beyond 2 minutes you will end up having a larger timecode number than actual time passed. 4 minute NDF time code (00:04:00:00) is actually 00:03:59:26 in time passed. DF, therefore is preferred if you want an EXACT reading of actual time passed because it compensates for actual video "speed" of 29.97 by jumping ahead 2 frames at the 2 minute mark.
Remember, this is only a counting implementation, and both NDF and DF write the EXACT SAME video frames in succession. It is only the way the numbers count up that is different, with DF keeping exact pace with time and NDF simply counting up 30 frames for every second of time, with video moving at 29.97 frames every second.
Whew.
Rich Rubasch
Tilt Media
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• | | | | | Re: Drop frame vs. non-drop frame
by Robert Dombaj on Aug 25, 2003 at 1:50:41 am |
Rich,
Thanks for your time answering my question. I now sort of get the whole logic between DF. Yes, I'm using DF striped D Beta tapes and my timeline is set to DF. However, I'm having a difficult time applying this DF theory to my situation. Basically, I'm trying to figure out if what I did in my last edit session was correct, OR, does it even matter. Like I said in my original message, I have a timeline that starts at 10;00;00:02, the whole project is about 1 hr 15 min. long. There are about 30-35 clips on the timeline. They are usually between 10 sec. and 2 min. long. They are spaced apart by 10 sec. of filler. Each clip starts at XX;XX;XX;02, however, the log going to master control says that clips start at XX;XX;XX;00. Should the log be corrected so that master control gets the EXACT time as it is on my timeline. Or should I not worry about it?
Shoot, I hope I'm making sense.
Robert D.
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• | | | |  | Re: Drop frame vs. non-drop frame
by Charlie King on Aug 25, 2003 at 6:20:41 pm |
Robert,
I have always worked in DF, because I started in broadcast and needed an hour program to be an hour and time code was my way to keep it at that. I stayed with DF for all projects, because I didn't want to have to think abvout what the end result would be and how I needed the time code. I was consistent. and yes when I was doing 30 second commercials, the first spot started at 1:00:00:00 and my system is set to always add when the 00 and 01 frames don't exist so the time will start on the 02 frame if I put in a time code of 00. I just don't think about it and everything does what I want it to do.
I hope I don't confuse you more with this explanation.
Charlie
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• | | | |  | Re: Drop frame vs. non-drop frame
by Elyse on Sep 4, 2003 at 1:00:14 am |
Hey Robert!
Like Charlie, my work has always required drop frame timecode. And my start time is always at the hour, straight up...i.e. 01;00;00;00. I have found it to be frame accurate, with a clean in and out.
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