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Question

What's the deal with Drop-Frame / Non-Drop-Frame Timecode?

Forum|Forum|13 years ago
December 14, 2012
3 replies
57929 views

I'm having trouble with 30fps Drop-Frame and 30fps Non-Drop-Frame timecode formats! I thought 29.97fps means 30fps Drop-Frame, but now I'm all confused.

I'm working with DSLR footage filmed with a frame rate of 29.97. For example, this one clip is listed as (in Project panel)

Media Start: 11:16:11:23

Media End: 11:22:42:22

Duration: 00:06:31:00

Frame Rate: 29.97fps

If I open this clip directly in Source Monitor, the timecode display (yellow, on lower left corner) says 11:16:11:23 at the beginning and 11:22:42:23 at the end. OK. But if I right-click on the timecode display, the pop-up indicates "Non-Drop-Frame"(!!). If I manually change that to "Drop-Frame", the start and end timecode would become 11:16:52:11 and 11:23:23:23, and the duration display (white, on lower right corner) becomes 6:31:12.

Now I create a new sequence of 1080p30, which has a 29.97fps time base. I right-click the yellow timecode display on the upper left corner of the Timeline, it says "30fps Drop-Frame". I drag the said clip onto the sequence. It occupies a length of 6:31:12. If I double-click the clip to open it in Source Monitor, now the Source Monitor timecode display indicates "Drop-Frame", and the start/end timecodes are 11:16:52:11 and 11:23:23:23. Huh??

Now I apply the "Timecode" effect on the clip. The timecode burn-in says 11:16:51:11 at the first frame and 11:23:23:22 at the last frame. I then go to the Effect Controls tab and look at the Timecode effect. It says

Format: SMPTE

Timecode Source: Media

Time Display: 30 Drop Frame

Just playing around, I switch "Timecode Source" to "Clip" - now the timecode burn-in goes from 00:00:00:00 to 00:06:31:11 - and then I switch it back to "Media". Now the Effect Controls tab says:

Format: SMPTE

Timecode Source: Media

Time Display: 30 Non-Drop Frame

And the timecode burn-in says 11:16:11:23 at the first frame and 11:22:42:22 at the last frame!

HUH??

Just for kickers, I switch "Timecode Source" to "Clip" again... Now "Time Display" stays on "30 Non-Drop Frame", and the timecode burn-in goes from 00:00:00:00 to 00:06:30:29.

What's the REAL length of this clip? Is it drop-frame or non-drop-frame? What are the REAL timecodes for it?

Also in a general sense, since I can change the "Time Display" field in the Timecode effect at any time, and change the Timecode display format of the Timeline at any time... How do I avoid creating mismatching timecodes??

Thanks in advance for any clarification!!

This topic has been closed for replies.

Zooropa75Author

Known Participant

I'm sorry, but my main questions still remain unanswered. I really need to get this resolved before I can move forward with this project, because the time codes will be used to guide our editing. The problem is, which time code??

My original post was long so I'll summarize it in simpler fashion:

I have HD footage from a Panasonic AF100 camera, and it's supposed to be 29.97fps. Which I thought means Drop-Frame Timecode.

When I did "New Sequence from Clip", the sequence that was created uses NON-DROP-FRAME Timecode. In this case, the clip's duration and time codes are consistent with how they were listed in Project Panel.

However, when I create a new sequence using one of the templates (such as 1080p30), the sequence uses DROP-FRAME Timecode. If I drag and drop the clip into this sequence, the clip's duration and start/end time codes CHANGE TO SOMETHING DIFFERENT.

Do you see how that's a problem?? If I had a clock in the picture, I would be able to verify which way is "correct". But there isn't.

I'm so frustrated with this that I may have to switch back to FCP for this project, which I don't really want to do!

J

Jim Curtis

Inspiring

Your question has been answered.

I have HD footage from a Panasonic AF100 camera, and it's supposed to be 29.97fps. Which I thought means Drop-Frame Timecode.

This is evidence of your misunderstanding. Maybe you should go back and carefully re-read.

It's normal for the Sequence durations to change when swapping between DF and NDF. Which method you choose is usually specced by your distro channel. IOW, they'll tell you whether they want DF or NDF. Again, broadcasters generally want DF, because it more accurately reflects real time.

You can select which method you prefer in the Sequence Settings > Settings > Display Format dropdown.

J

Jim Curtis

Inspiring

Maybe I'm missing something but I still don't understand.

The footage comes with a timecode on it. I was hoping this timecode matches the "real time" of how things happened.

I also thought that 29.97fps footage comes with timecode that drops two frames every minute, except for every ten minutes. And this is called Drop-Frame Timecode.

From what Jim S said, it seems like 29.97fps footage could come with either DF or NDF timecode? (The footage came from external source so I don't know how the camera was set.)

If the footage indeed came with NDF timecode, does that mean the timecode does NOT match the "real time"? In other words, if the interview was exactly 1 hour long, the timecode on the footage would indicate it's a few seconds shorter than one hour?

Jim C, you are right, when the timecode changes between DF and NDF, the footage durations appear to change. So obviously, only one of them could be "correct" in terms of reflecting what actually happened. The other one is slightly sped-up or slowed-down. You might say "oh that's a tiny difference, it doesn't matter". But it really could matter in longer projects, or when we have people review footage and communicate their comments based on timecodes. So when I have hours of footage and I want to do a timecode burn, I would like to know which timecode is the "correct" one!

The footage comes with a timecode on it. I was hoping this timecode matches the "real time" of how things happened.

IF it was recorded DF. You can usually tell by the separators in the code reader in software: 00;00;00;00 for DF; 00:00:00:00 for NDF. Colons or semi-colons.

From what Jim S said, it seems like 29.97fps footage could come with either DF or NDF timecode? (The footage came from external source so I don't know how the camera was set.)

Correct. Depends on how the camera was set-up.

If the footage indeed came with NDF timecode, does that mean the timecode does NOT match the "real time"? In other words, if the interview was exactly 1 hour long, the timecode on the footage would indicate it's a few seconds shorter than one hour?

Correct. NDF is NOT real-time.

You might say "oh that's a tiny difference, it doesn't matter". But it really could matter in longer projects, or when we have people review footage and communicate their comments based on timecodes. So when I have hours of footage and I want to do a timecode burn, I would like to know which timecode is the "correct" one!

Correct again. It DOES matter if you need a reflection of real-time in your SEQUENCE.

If you're doing a time-code burn for purposes of logging or selection, make your burned TC mirror the source time-code. Then you shouldn't have any confusion.

Dragonspear

Participating Frequently

I've got an easy answer for you^^ But first, let me quickly tell you not to implicitly trust manufacturers listed frame rates. Many manufacturers will say things like "60p" or "24p" but in fact mean 59.94 and/or 23.38. Many times when you dig down into your camera manuel, you'll find the "actual" frame rates etc. Don't confuse whole numbers and their decimal counterparts with drop-frame and non-drop frame.

All you need to know is this:

Import your footage into Premiere.
Drag it onto the "Create New Sequence" button to ensure you create a sequence with the same settings as your footage.
Drag the "Timecode" effect onto your video clip.
Select "Media" from the source selection in the timecode effect.
TADA! Your timecode effect will match the timecode of your timeline.

IMPORTANT! For some reason I've noticed that even though the TC effect usually defaults to "Media" for the source, it will NOT show the proper TC until you manually select "MEDIA" from the selection. ...this is the case even when it already starts with it selected. ...weird I know, but that's how it is when I tried it. You have to click on the menu in the effect and then select Media even if it shows "media" when you first apply the effect. ><

PS. From what I can tell, you can trust your source window timecode setting. (right-click the yellow tc numbers you mentioned to see if it's drop/non-drop)

Hope that helps! ^_^

Zooropa75Author

Known Participant

Thank you, Dragonspear. That helps, although I still have some major questions.

Where is the "create new sequence" button? I only know to right-click and choose "New Sequence From Clip". Anyway, I did that with the clip in question, and the sequence created displays 30fps Non-Drop-Frame timecode. Which seems to imply that the clip carries 30fps NDF timecode. But the clip is supposed to be 29.97fps, which I thought means Drop-Frame. Indeed, if I create a new sequence with a "1080p30" template, either under AVCHD or HDV, I get a sequence with 29.97fps time base and DF timecode.

Here is my big question: When I view the clip with NDF timecode setting, or put it in a sequence with NDF timecode, its length is 6:31:00. When I view it with DF timecode setting, or put it in a sequence with DF timecode, its length is 6:31:12. How do I know which one is correct?? Meaning, what's the duration of the event that was recorded in this clip?

I also misspoke when I said this is DSLR footage. It's actually from a Panasonic AF100.

E

excited_Genie16B8

Legend

I only know to right-click and choose "New Sequence From Clip".

That's just as workable.

seems to imply that the clip carries 30fps NDF timecode. But the clip is supposed to be 29.97fps, which I thought means Drop-Frame.

Read post 1 again.

E

excited_Genie16B8

Legend

Simply put, DF and NDF are methods of handling timecode, and do not affect the frame rate of the media itself.

DF is the more accurate with regards to real time, and thus is much more widely used.

J

Jim Curtis

Inspiring

Jim Simon wrote:
Simply put, DF and NDF are methods of handling timecode, and do not affect the frame rate of the media itself.
NDF is the more accurate with regards to real time, and thus is much more widely used.

Jim, DF is more accurate with real time, because of the fractional nature of 29.97. The reason frame numbers are dropped is to keep the running total consistent with real time, and this is why broadcasters generally use DF code.

http://en.wikipedia.org/wiki/SMPTE_timecode#Drop_frame_timecode