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Is DV a drop frame only codec?
Is DV a drop frame codec only?
Scott Davis
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7 Replies
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Also, is 30 fps the same as NDF?
Thanks,
Scott Davis
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Nope.
Walter Biscardi, Jr.
Biscardi Creative Media
HD and SD Production for Broadcast and Independent Productions.STOP STARING AND START GRADING WITH APPLE COLOR Apple Color Training DVD available now!
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https://www.csif.org/html/dropframe.html
LINKY!
Shane
GETTING ORGANIZED WITH FINAL CUT PRO DVD…don’t miss it.
Read my blog, Little Frog in High Def -
Here’s the easiest way to remember the difference between DF & NDF.
The knuckleheads that invented DF made a HUGE MISTAKE by naming it “Drop Frame”. If they only would have called it “Drop Number” they could have saved countless people days and days of frustration. No “frames” are dropped… only numbers. The misunderstanding that exists regarding this one technical concept is astounding.
When I’m interviewing new assistant editor candidates I offer them $100 bucks if they can successfully articulate the difference between drop frame and nondrop frame timecode. I still have the cash in my pocket… although one person did get very close! Everyone gets it wrong. Even people who should know better.
If you ever want to separate the wannabees from the “do it alls”, just ask them to explain to you the difference between DF & NDF.
Mark
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Good article, thanks Shane. I think my head just exploded.
Scott Davis
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Drop frame attempts to keep the time on the VCR/VTR matching the time on the clock on the wall.
If video ran at 30 frames per second, in an hour you would have 30 * 60secs * 60 mins of frames go by, or 108,000 frames.
However, complete frames always go by, but they go by slower, so in an hour of clock on the wall, you actually have only 29.97 * 60secs * 60 mins, or 107,892 frames in an hour.
So the keep the VCR clock and the clock on the wall together, you have to make up that difference of 108 too many frames count in an hour. To do that, DF skips 2 frames of count at each minute mark. If you did that for every minute, you would skip 120 frames of count in an hour, which would not be 108.
To get 108 frames of count skipped, the 2 frames skipping does not occur on the even 10 minute marks. There are 6 of those (10, 20, 30, 40, 50, 00). So for 6 minutes out of each hour, no frame counts are skipped. For 54 minutes out of each hour, 2 frame counts are skipped. 54 * 2 frame counts = 108 frames, which is the magic difference between the theoretical 30 frames per sec used in the counting system, and the real 29.97 frames per sec that video actually uses.
Hey, my students might get that prize money, so watch out.
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To answer the original question, DV video can be either Drop Frame or Non-Drop Frame. Most consumer level camera default to Drop Frame but professional cameras can record either.
Tom
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