- [Voiceover] When it came to actually broadcasting NTSC
video, there was a problem with the signal transmission.
Without going into a long explanation, the solution was
to slow the video down to 29.97 frames per second at
the moment of broadcast but only at the moment of broadcast,
which confuses a lot of people.
When you record 29.97 frames per second footage on a camera,
for example, you're actually recording 30 frames per second
but with a special kind of timecode reading
that automatically drops exactly the amount of frames
to give you the duration that will apply
when the footage is broadcast.
If your footage is intended for the web, don't use
dropframe timecode as the duration won't actually match.
The ten minutes of footage recorded with drop frame
29.97 frames per second time code will not last ten minutes.
It will be slightly shorter in real playback duration.
However, if you were to broadcast that footage, it would
be slowed down during broadcast so that the 29.97 frames
per second drop frame timecode gave the correct duration.
I can sense your disbelief
but just try it with your own stopwatch.
Only NTSC video uses drop frame timecode.
When PAL video was broadcast, it didn't have the radio
transmission problem and it wasn't necessary
to slow down transmission.
When new frame rates became available for video,
in particular, 24 frames per second video intended
to mimic the appearance of film recording,
the drop frame rule still applied.
The playback speed will be slowed for broadcast
by one percent just like 30 frames per second video.
So you'll find cameras give you the option to record
23.976 frames per second or 29.97 frames per second.
I should say that number is sometimes abbreviated to 23.98
frames per second.
These options just change the way the timecode counts,
deliberately not counting some of the frames
to make the reading match the broadcast duration.
Again, regardless of the frame rate you're recording,
drop frame timecode is only relevant and useful
if you intend to broadcast your video.
I didn't believe this when I first learned it
and I tested it with footage and a stopwatch.
It's crazy but it's true.
You can always identify dropframe timecode because it has
semicolon number separators rather than colons.
That visual clue gives you important information about
the way time is being measured for your video footage.