Drop Frame Time Code Reference Point

Posted by Jackson 
Drop Frame Time Code Reference Point
May 02, 2008 09:03PM
I hope this is not too off topic to annoy, but I'm sure many of you have a quick and easy answer for me.

I have just finished mastering my film on HD at 23.98 and my deliverables requirement is to provide a drop frame time code DigiBeta cam for broadcast.

SOP for mastering to Warner Bros. specs require 30 sec black, 1 minute bars and tone, 10 sec black, 10 sec slate, 10 sec black, first frame of action.

If I check the drop frame time code check box in the time line starts at 00:58:00:02 because 58:00:00 does not exist in dftc. I can cut my seq by a couple of frames no harm done, but my bars and slates and first frame of action do not start precisely on the time code frames the are supposed to because I have too many frames to fit into that time code. Do I line up my first frame of action to 01:00:00:00 and let my leader slip down to first frame of action and then slip up for the rest of the program or do i pull the extra frames out of the leader, or do I just let is fun from 00:58:00:02 and lets the damn 4 four frames fall where they may?

(I say "slip" in reference to the dftc against true frame count of ndftc. No need to explain dftc to me, I know it well.)

Anal? Yes. But single frame precision is the would we work in.

- Jackson

UPDATE: The reason I ask is I render out a QT of the HD Master SQ to a 29.97 file, then drop a TC Reader filter on it to include a viz window for the Closed Captioning and Transcription folks. TC Reader reads the clip time code, not the Sequence time code. Quicktime Conversion nor Compressor have a non-drop vs. drop-frame time code setting. Your QT automatically is non-drop. I want to avoid the extra step of having to put the clip in a drop-frame sequence and output yet again to make it drop-frame.
Re: Drop Frame Time Code Reference Point
May 02, 2008 09:19PM
I'd go with starting the show at 1:00:00:00 and let the bars and slates start wherever they have to for that to happen. That's the only fame that matters once it gets into the hands of the people who load it into a server or automatic playback system.
That's not being anal that's just being smart. Your DF and NDF should always start from XX:00:00:00 on the same frame of the program. I doubt anyone is checking that your bars start on a specific TC. They might be the ones who get anal about duration of bars or slate though.

ak
Sleeplings, AWAKE!
Re: Drop Frame Time Code Reference Point
May 03, 2008 02:53PM
Jackson-

One more thing to be careful about with drop frame. If your program has a specific duration provided to you by Warner you could have some issues.

NTSC Video runs at 29.97 frames per second, time code labels each frame as if there were 30 in each second. The purpose of drop frame timecode is to keep the running program in sync with real time. It does this, as you noted, by skipping some numbers in the count.

At the end of a 1 hour show the accumulated difference is 3 seconds and 18 frames. Your program my run a bit long. As you cut your program at 23.98, this may not happen. However it may be wise to check your program length and break hit times before you ship the master.

-Vance
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