Behind the Orange Curtain

This week we are back to a techie topic that actually comes from a question from client at Gear Monkey.  It involves frame rate and time code.  Specifically, how does frame rate affect time code and what are the differences between the various frame rates like 30p, 29.97, 24 and 23.98?  I will try to keep this one brief and concise so that no one’s brains melt and ooze out of their ears.

First, let’s address time code.  There are essentially two types of time code, drop frame and non-drop frame.  Drop frame time code was created to account for the extra amount of time that it took to broadcast the color portion of the television signal when NTSC was invented.  In order for the time code to match the actual elapsed amount of time, two frames needed to be dropped every minute but not every tenth minute.  During a discussion a few years ago on this subject I asked a group of editors when they thought it was appropriate to use either type of time code.  One editor responded, “Don’t they use drop frame on the east coast and non-drop on the west coast?”  I have never forgot that answer.  The bottom line is that if you are working in standard definition NTSC and will be broadcasting your program (obviously this doesn’t matter for commercials since the program has to be longer than a minute before it matters) then use drop frame time code, otherwise non-drop is fine.  In fact, in any HD format there in no drop frame because you do not need to compensate for the NTSC color delay.

Now, with regard to the varying frame rates available to us in the brave new HD world, here are some tips.  Firstly, let me clarify a few things.  23.98 and 23.976 are the same thing.  The abbreviated 23.98 uses that complex mathematical function known as “rounding.”  Wouldn’t my high school math teacher be proud?  However, 23.98p and 24p are NOT the same thing and I have seen the pain in the eyes of those who have made the wrong choice.  Any footage that will be broadcast or laid off to videotape for final mastering should be done in either 23.98p, 29.97p(or i) or 59.94p(or i).  It is now possible with the advent of things like Final Cut Pro and file based camcorders to create and edit true 24p or 30p projects.  This is fine if your distribution will only be via computer display or if you are printing back to film, however if you want to lay that project off to videotape or broadcast it you will be bummed when you have to re-render that project from 24p to 23.98p or from 30 to 29.97.  I will spare you the long explanation and to why this is, but it has to do with the 60Hz power source we have in the USA and other places.  Some  video cameras refer to 24p or 30p when they are actually referring to 23.98p and 29.97p (i.e. SDX-900, DVX-100, HVX-200, etc.)  If you are shooting with a video camera, you can be fairly certain that you are shooting in either 23.98, 29.97 or 59.94 (i.e. Varicam).  Just make sure that you set up your Final Cut or AVID project accordingly.  For more on this see this older post. 

Feel free to post additional related questions as comments to this post.  In my next post, I will address the issues of color space and color recording formats in current formats.  Happy producing!