To Drop-Frame or not?

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rpwooste

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To Drop-Frame or not?

PostThu May 16, 2019 2:01 pm

The BMPCC 4K is my first camera with the option to select either Drop Frame or not - for 59.94fps shooting and editing, is it better with Drop Frame on or off? Does it make any difference during editing, playback reliability and support on various devices, or upload to youtube?
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Andrew Kolakowski

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Re: To Drop-Frame or not?

PostThu May 16, 2019 9:12 pm

It's just time code and it means not much at all.
Drop frame TC will sync with real time, but for "home editing" it's not important.
It has nothing to do with quality etc.
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JPOwens

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Re: To Drop-Frame or not?

PostWed May 22, 2019 6:37 pm

Andrew Kolakowski wrote:It's just time code and it means not much at all.
Drop frame TC will sync with real time, but for "home editing" it's not important.
It has nothing to do with quality etc.


For the most part, it's a broadcast deliverable for domestic North American. Broadcasters need a "clock-time" run duration and cue sheet for text, breaks, &c.

DF HR:MN:SC;FF is a kludge to offset the 108 frames that result in a Non-Drop Timeline counting "slow" at 59.94 fields, resulting in a "heavy" hour.

https://evertz.com/resources/The-Right-Time.pdf

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Andrew Kolakowski

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Re: To Drop-Frame or not?

PostWed May 22, 2019 7:16 pm

Yes, broadcasters prefer DF as it matches clock time, but you can do whatever you want for shooting as this will matter only on your final render (if it goes to broadcast at all). You can also (at least for MOV) quickly swap DF/NDF even after export (with specific tools).
Other time when it matters is when you're going to cooperate with other people and then all of you should work to the same timecode. Then you decide up front if it's DF or NDF and stick to it.
Point is that timecode is just a metadata which has nothing to do with video or audio itself.
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brentf

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Re: To Drop-Frame or not?

PostMon Feb 03, 2020 6:26 pm

Trying for understanding and clarity: Isn't the 'Frame Rate' of the camera... i.e. the rate at which frames of picture are generated, separate from 'Time Code'... i.e. the rate at which frames are marked?

A camera doesn't actually capture only 59.94 frames in a second, right? It's capturing 60, but we're stamping it with Time Code of 59.94? (same with 24 vs 23.98)

In post, our project settings have to be correct for the capture rate of the picture, but we can set the Time Code display to be anything we want (at our own risk of confusion of course) on the fly at any time. To me, this demonstrates that Time Code is separate from video capture rate.

I'm an audio guy, not a picture guy, so I'm constantly at the mercy of the picture department relaying their settings to me correctly. Results in post have been quite mangled when things aren't accurate. Also saying that to let you know my grasp on picture standards is tenuous.
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Andrew Kolakowski

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Re: To Drop-Frame or not?

PostMon Feb 03, 2020 9:39 pm

TC is just a way how we count frames. The best "timecode" is actually a frame count.
DF TC is special math to fix "mismatch" for counting based on eg. 30 vs. 30000/1001.
There is no such a thing like "29.97 frames". It's still 30, but counted by special formula.
It's yet another legacy crap which can go to the past now. We can all move to new fps standard, eg. 60fps which will simplify everything. Fractional fps is so useless these days.
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Howard Roll

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Re: To Drop-Frame or not?

PostTue Feb 04, 2020 3:28 am

brentf wrote:A camera doesn't actually capture only 59.94 frames in a second, right? It's capturing 60, but we're stamping it with Time Code of 59.94? (same with 24 vs 23.98)


This part is precisely backwards. The camera is recording at 59.94, it's counting 60.

There is also a real 60fps. It's the devil's work. We will never mention it again.

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Andrew Kolakowski

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Re: To Drop-Frame or not?

PostTue Feb 04, 2020 12:28 pm

More precisely- camera is recording at every 1/59.94 (more precisely 1001/60000) of a second.
It's all way simpler when it's integer number: 25, 30, 60 etc. Those "funny numbers" were needed due to analog TV, but today can be forgotten (same as interlaced recording).
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Marc Wielage

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Re: To Drop-Frame or not?

PostSun Feb 09, 2020 1:30 am

Andrew Kolakowski wrote:More precisely- camera is recording at every 1/59.94 (more precisely 1001/60000) of a second. It's all way simpler when it's integer number: 25, 30, 60 etc. Those "funny numbers" were needed due to analog TV, but today can be forgotten (same as interlaced recording).

That is not true. Digital broadcasting in America still uses Dropframe for deliverables, 1080i. They do it because (as @Joe Owens says above) there's a 3-1/2 second error every hour between normal "non-drop" timecode and dropframe.

We typically finish shows in 23.976 -- which is only "normal" timecode -- and then at the very end of the process, convert to 29.97fps Drop with 2:3 pulldown inserted. The trick is to understand that the show needs to run a little shorter so that you don't run over in dropframe-land. Good post people have the formulas down so they understand where to pull up a second here or there so it times out correctly.

I would love to see dropframe completely go away, but it's still a reality for countries using 60Hz-based power and transmitters.
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Andrew Kolakowski

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Re: To Drop-Frame or not?

PostSun Feb 09, 2020 11:58 am

Yes, because they are so outdated and no one wants to change as it costs money. Switch to 60Hz and solved :D

Similar thing is in Europe with 50i and 25p. BBC for example stopped transmitting movies as 50i (which causes some TVs trying to do not needed deinterlacing). They use 25p for movies and other shows originated in 25p and 50i for sport etc. In next few years they could even move to 24p for movies as basically all TVs at households will support it (it may not be true now).
Look at eg. Netflix. They use native for the show fps and this is how it should be. It's stupid politics to prevent eg. USA TVs support 50Hz (is it still true?). In Europe we have no problem watching Netflix at 23.976p, 24p, 29.97p, 30p etc. There is no real need (except political one) for any speed-ups, 3:2 pulldown, or conversion these days.
Does Netflix in USA work with 25p?

You have a problem with DF even if you natively shot for USA. Tell this for post houses in Europe which work to 25Hz. Then you end up with this stupid problem of 1 missing/too much frame ( or TC not starting at 01 or 10 if you do conversion).
At the end it's just metadata which has nothing to do with the actual video. When you collaborate you need to agree one type DF/NFD and stick to it and because broadcasting needs to work to real time they use DF, so you need to follow. Well, you don't have to during your work (you can even use frame number as reference). What counts is final delivery and this is where problems starts- some places want A, other B, another C, etc. and you end up with so many delivery versions. Sometimes difference is just DF vs. NDF flag, or even more 'stupid' things like 16bit vs. 24bit PCM or 10h based TC vs. 01h one :D
Trying to agree on 1 format proved to be simply impossible. It sort of works in UK now, spreading to some other European countries, but still far from having wide coverage.

Funny is that there is really no official 23.976 DF timecode ('normal' 24p applies), although some tools do have such a thing.
Legacy fact. In Poland for example they just turned off last analog transmission (some cable providers still had it on even when about no one was using it). I assume now it's gone for good. Main move to digital was actually in 2013.
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Howard Roll

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Re: To Drop-Frame or not?

PostSun Feb 09, 2020 5:30 pm

Until that golden day when true integer framerates arrive, drop frame overwhelmingly makes the most sense.

Using non DF timecode would only make sense in a reality where we describe time in frames not seconds.

The alternative is literally frame add seconds. Timecode clocks couldn't tell time. How would you request a 30 sec spot? Who makes that adjustment? The ideosycracy is created to support our language so we don't need to create a new one. The implications are much more far reaching than sync between devices.

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Marc Wielage

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Re: To Drop-Frame or not?

PostMon Feb 10, 2020 10:44 am

Andrew Kolakowski wrote:Yes, because they are so outdated and no one wants to change as it costs money. Switch to 60Hz and solved

I live in the real world, where we have real clients, real spec sheets, and they rely on us to give them what we ask for. We do that. I have seen trainwrecks happen in post where (say) well-intentioned production companies in Japan provided a master at 60Hz, only since we only deal with 59.94 in American broadcasting, we immediately ran into speed/sync problems. The need for precise, written delivery specs cannot be underestimated.

Funny is that there is really no official 23.976 DF timecode ('normal' 24p applies), although some tools do have such a thing.

Nope, no such thing as 24fps drop or 23.976 drop.
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Andrew Kolakowski

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Re: To Drop-Frame or not?

PostMon Feb 10, 2020 6:56 pm

Yes, because no one needs it.
Last edited by Andrew Kolakowski on Mon Feb 10, 2020 7:05 pm, edited 1 time in total.
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Re: To Drop-Frame or not?

PostMon Feb 10, 2020 7:04 pm

Marc Wielage wrote:
Andrew Kolakowski wrote:Yes, because they are so outdated and no one wants to change as it costs money. Switch to 60Hz and solved

I live in the real world, where we have real clients, real spec sheets, and they rely on us to give them what we ask for. We do that. I have seen trainwrecks happen in post where (say) well-intentioned production companies in Japan provided a master at 60Hz, only since we only deal with 59.94 in American broadcasting, we immediately ran into speed/sync problems. The need for precise, written delivery specs cannot be underestimated.

Funny is that there is really no official 23.976 DF timecode ('normal' 24p applies), although some tools do have such a thing.

Nope, no such thing as 24fps drop or 23.976 drop.


Yes, but all these requirements exist due to technology needs from ages ago.
Time to move on- interlaced and fractional fps are first to go as they are obsolete these days. You gain 0 except issues from their existence.
I'm so happy that interlaced modes don't exist for UHD :D
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Marc Wielage

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Re: To Drop-Frame or not?

PostTue Feb 11, 2020 6:06 am

Andrew Kolakowski wrote:Yes, but all these requirements exist due to technology needs from ages ago.
Time to move on- interlaced and fractional fps are first to go as they are obsolete these days. You gain 0 except issues from their existence. I'm so happy that interlaced modes don't exist for UHD :D

Again: it's not my decision. It's the client's decision. If you had a client that said, "I want to pay you $20,000 to color-correct my feature, and I want it delivered in 29.97 drop frame and interlaced video," would you tell them to get F'd?

No. The job of the colorist is to give the filmmakers what they want. If I were in that position, I would say, "let's master it completely in 24p or 23.976p, and then at the very end, we will create a deliverable file that is exactly what you're asking for." And we would suggest they archive the 23.976 version, which is pretty standard.

This is not a philosophical argument about what we wish the world would be. I deal with the way the world is. I'd gladly give the client a drop-frame master if that's what the specs called for. But we're clear in our client contract that they agree once we deliver what they ask for, we get paid. If they want something different, that's another charge. So it's really a question of time and money, not whether or not the spec is outdated.

Have you ever delivered commercials or episodic TV for the United States? If you did, I suspect we wouldn't be having this discussion.
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Re: To Drop-Frame or not?

PostTue Feb 11, 2020 7:50 am

A lot of people overlook the need to deal with old formats in documentaries etc. One still must understand and deal with interlacing and odd frame rates simply because producers and directors throw that old footage at an editor and require them to understand it and deal with it so there are no weird artefacts when using it in a contemporary edit.

I had to do a doco where the edit was from 25fps conversions from 29.97 TV & 24fps DVD versions of 24fps film. Then we received the original sections from the USA in 24fps, 29.97 and 30 fps (both drop & non-drop timecode) and had to make it perfectly match the 25fps conform sent to audio.

These old formats should be understood and dealt with as they are the formats in the archives! Until everything is converted to a universal standard, (which does not yet exist) it ain't going away!
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Re: To Drop-Frame or not?

PostTue Feb 11, 2020 11:56 am

Marc Wielage wrote:
Have you ever delivered commercials or episodic TV for the United States? If you did, I suspect we wouldn't be having this discussion.


Very opposite. I deliver world wide, sometimes 100s hours a week of very different content- from movies to news. It's me who takes colorist work and makes 100s of versions of it. Actually, once you start delivering world wide real fun starts.
I also do what client wants, but this is not the point. Specs are very outdated same as whole post in many cases. No one is interested in moving forward as it costs money and todays world is all about $. If you take such a distant approach then this is exactly why we still so heavily driven by the past.
Last edited by Andrew Kolakowski on Tue Feb 11, 2020 12:07 pm, edited 2 times in total.
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Andrew Kolakowski

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Re: To Drop-Frame or not?

PostTue Feb 11, 2020 12:03 pm

Peter Cave wrote:A lot of people overlook the need to deal with old formats in documentaries etc. One still must understand and deal with interlacing and odd frame rates simply because producers and directors throw that old footage at an editor and require them to understand it and deal with it so there are no weird artefacts when using it in a contemporary edit.

I had to do a doco where the edit was from 25fps conversions from 29.97 TV & 24fps DVD versions of 24fps film. Then we received the original sections from the USA in 24fps, 29.97 and 30 fps (both drop & non-drop timecode) and had to make it perfectly match the 25fps conform sent to audio.

These old formats should be understood and dealt with as they are the formats in the archives! Until everything is converted to a universal standard, (which does not yet exist) it ain't going away!


Not talking about what already exists, but new or what is not even there yet.
There is some progress. For example a lot of latest drama in UK is now pure 25p, where it use to be 50i (or sometimes worse- mixture of 25p and 50i). Some post houses took a good approach and don't do 25p master with rolling credits as 50i, but use static credit pages and keep it 25p. Sounds nothing, but makes huge difference later.
Old content is in most cases problematic and needs careful approach (which costs money).
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Marc Wielage

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Re: To Drop-Frame or not?

PostWed Feb 12, 2020 7:04 am

Peter Cave wrote:A lot of people overlook the need to deal with old formats in documentaries etc. One still must understand and deal with interlacing and odd frame rates simply because producers and directors throw that old footage at an editor and require them to understand it and deal with it so there are no weird artefacts when using it in a contemporary edit.

Very true. CNN in America has been doing some terrific "decade" shows (The Sixties, The Seventies, The Eighties, etc.), and they have to pull in a vast amount of archival material: 2" videotape, 1" videotape, 16mm kinescopes, 16mm film, and -- worst of all -- 16mm film that had been telecine'd to standard-def video. When it has 2:3 pulldown embedded, it's hard to undo that.

For these shows, they finished them all at 1080i 29.97 -- and, yes, at drop-frame, since that's the network standard for the U.S. -- and that became the common standard for all their conversions. Generally the shows look very good, but once in awhile you'll see a few shots that have horrible artifacts that they just weren't able to undo. Given the challenge they're dealing with, it actually looks amazingly good to me. The CNN documentaries, done by the Herzog company in Burbank, are about as good as this kind of show gets.
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Andrew Kolakowski

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Re: To Drop-Frame or not?

PostSun Feb 16, 2020 6:03 pm

Marc Wielage wrote:... 16mm film that had been telecine'd to standard-def video. When it has 2:3 pulldown embedded, it's hard to undo that.
.


2:3 is not that hard if you use correct tools. Unfortunately I don't know a single pro tool which gives you proper handling of mixed/edited masters with 3:2 pulldown. Open source tools simply destroy any pro ones in this area.
Last edited by Andrew Kolakowski on Mon Feb 17, 2020 6:23 pm, edited 1 time in total.
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Peter Cave

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Re: To Drop-Frame or not?

PostMon Feb 17, 2020 12:35 am

Andrew, that is not my quote!
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Andrew Kolakowski

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Re: To Drop-Frame or not?

PostMon Feb 17, 2020 6:23 pm

Strange that it got formatted to this result (actually on editing it I can see how it happened).
Sorry, fixed.
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Marc Wielage

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Re: To Drop-Frame or not?

PostTue Feb 18, 2020 3:50 am

Andrew Kolakowski wrote:2:3 is not that hard if you use correct tools. Unfortunately I don't know a single pro tool which gives you proper handling of mixed/edited masters with 3:2 pulldown. Open source tools simply destroy any pro ones in this area.

I call it 2:3 pulldown because SMPTE and most networks changed their specs in the 1990s. We had been doing 3:2 pulldown pretty indiscriminately in the 1980s, but by the 1990s we finally had telecine editing gear that was more field-aware and could prevent splitting fields and other problems. The issue, though, is what do you do with a show that was shot on film, transferred to tape, and then the tape was edited? The tape is not "aware" of where the film fields are, and so you get split fields all over the place whenever they make an edit. It's a very, very complicated technical problem for which there is no easy solution.

Note that we even had this problem in the 2000s with HD telecine in 1080i, which was a bit of a nightmare. I was glad to see that go away for color correction, for the most part. Most of the stuff we worked on from about 2002 on was 23.976fps progressive or PsF, and worrying about interlacing went away. Only when the shows were finished were they then transcoded over to 1080i and drop-frame for broadcast.

Now, if you try to pull one of those shows into a 24p or 23.98p project, it will definitely have some problems.
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Andrew Kolakowski

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Re: To Drop-Frame or not?

PostTue Feb 18, 2020 10:37 am

This is exactly what I'm referring to. Masters with broken cadence due to editing etc.
There are open source tools which deal with it well. They keep tracking new patterns and recover progressive frames well. You may still need to touch few places, but it saves you so much work.

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