23.98 FPS work-around?

Hi JHK,

Sure, normally you'd want to set the frame rate of Logic to the actual frame rate of your movie to get Logic's timecode counter to match that of the timecode burn to ensure sync. Of course this is important to get aligned, but as I've found over the past few weeks working on a 23.98 movie, not really all that necessary... Instead...

I did a test with my editor by grabbing the dialog from the QT movie with Logic set to 29.97 as well as 24 fps. I took a 5 minute piece, popped it at head and tail according to the movie's timecode burn and sent them to the editor. When he laid them up against picture he had perfect sync, and my pops lined up precisely where I said they should.

And by "precisely" I mean that I am very careful to place pops on the leading edge of a frame. This means finding the frame ("X") that you want to pop, and then scrolling Logic's SMPTE bits backwards in time until you see the previous frame. Then you scroll the bits forwards carefully until "X" appears again. A little rocking back and forth of the bits value, ending up on the very first bit that will display frame "X" will ensure that your SPL is aligned exactly to the leading edge of the frame.

Then I place a 2-pop sample on a track and using a key command, have it move to the SPL position. I do the same for my tail pop. Done.

So, in short, I'd suggest forgetting about the complicated business of pull-down or any other kind of conversion. Just run the movie in Logic at 24fps or 29.97 (it actually doesn't matter) and reference the movie's timecode. It may seem a little strange to work this way, as it did me, but I got used to it very quickly.

BTW, every cue I've submitted so far using this method has aligned perfectly.

HTH

-=iS=-

Very interesting to know, thanks for the response.
So, are you actually now running at 29.97 for the
project or 24?

Turns out that I'm running different cues at different frame rates (either 24fps or 29.97fps) to a final cut that's at 23.98 fps. It's a long story as to how it ended up that way, but it's proving not to be a problem at all. In fact, Logic's FPS setting relative to the movie doesn't seem to matter at all, at least in this case.

OK, gonna give you my whole shpiel on this subject...

If:

• a full-frame QT movie at 24, 25, 29.97, 30, or 23.98 has embedded audio tracks recorded at 48K (standard)

• there hasn't been any pull-up or pull-down in the process of preparing that movie

• contiguous sync is switched off

• Logic is set to 48K

• the movie is set to play back from Logic at 1 1 1 1 from its very first frame (no movie start offset)

• that audio is extracted from the movie to the arrange window (which will also now start at 1 1 1 1)

...then regardless of Logic's frame rate setting, the extracted audio will remain in sync for the length of the movie.

In fact, I just did a test... I set Logic to 24 fps and loaded up a 1-minute long 23.98 QT movie. I recorded the embedded audio back into Logic via simple loopback (audio output for my QT movies shows up on 2 channels of my mixer; bussed them back into Logic and recorded the audio on a track).

Then, without changing anything other than Logic's frame rate (which I changed to 30 fps) I recorded the audio again on another track. I put one track out of phase and heard a slight flamming (this is to be expected because of variations in the QT codec). After a minor adjustment of the sample start point in the second track I was able to get the audio aligned to the point where I had complete cancellation of the audio for the full one minute.

This proves that Logic's frame rate setting has no bearing on the playback speed of the QT movie, and therefore, no bearing on the playback speed of the audio. The 48K clock governs the speed of the audio, not the QT codec.

In fact, a QT movie does not have any kind of embedded timecode "signal" contained within its data. The timecode burn is nothing but an image of a timecode number added to each frame of video. So really, a timecode burn is just a number-changing-cartoon that's overlaid onto the actual picture. So the timecode burn isn't connected to anything and doesn't drive anything. It's just a visual reference.

The long and short of it is that you can set Logic's frame rate to anything you like -- even the wrong frame rate -- and you can still score with accuracy provided that you reference the picture's time code.

Having said that, life is MUCH easier if Logic's timecode counter is perfectly in sync with the picture's timecode burn. But it's not a technical necessity.

If I have time later I'll address your other points, but for now, gotta run.

-=iS=-

Message was edited by: iSchwartz

I think you might have missed my point (or maybe I was long-winded enough that I couldn't blame you if you did! LOL!)

It won't matter if you're working at 44.1 or setting the movie start time to different places for each cue. My point was that Logic's frame rate setting doesn't matter in the big picture. No pun intended... : - )

If you work at 44.1, fine. Just do your thing at 44.1, and set the frame rate for 24 or 29.97. Your choice. When you print your mixes, pop them at head and tail according to my suggestion above (regarding placing your pops at the frame edges). Then sample rate convert to 48 for delivery. This should result in a file where, when your editor lays it up with the head pop exactly on the money, your tail pop will be off, at most, by a few bits. Trust me, that's gonna make a good impression on even the fussiest editor.

Finally, contiguous sync is a parameter that appears when you click and hold on the movie window. I recommend unchecking it always.

Hey JHK,

My current workaround is to sync logic as iShwartz has mentioned (I'm working at 25fps to a 23.98fps QT). Then I mixdown to PT (again sync'd at 25fps) the latest version of PT allows for an alternative frame rate to be displayed in the time ruler which can be referenced in the transport at any point. This allows for a double check that I am happy with and it allows me to send my music editor cues with an accurate TC reference even if I haven't been provided with BITC which, as we all know is never a certainty.

But doesn't this bring us to the next question? What's going on with Logic chaps? It's actually starting to look and feel a bit old and grumpy "23.98 why would you want to work at a frame rate like that? I don't know these fancy wancy new HD cameras that those namby pamby people in Hollywood seem to be using I don't know....". Hands up who else will be really dissapointed if we don't have a mega new upgrade announced at WWDC?

I used Waveburner for the first time in ages the other day and it left me with a real sense of Logic being left waaaay behind. "Why doesn't logic feel and look like this" I questioned myself.

Anyway, sorry for hijacking your thread with my own old and grumpy musings.

Christian,

Thanks for your support of my method. When I started on my project 'for real' (i.e., once I got past the sketch stage) I dreaded the idea of having to deal with a 24fps Logic frame rate and a 23.98 fps picture. But it proved not to be terribly difficult after all. Basically, starting from the first cue (titles), once I got Logic's t/c counter to jibe with the the t/c I saw on picture, I just stopped paying attention to Logic's timecode counter after that. The only time I used it was when I was jockeying bits to get the SPL to move to the leading edge of the frame I wanted to pop.

If an update of Logic doesn't include 23.98... Per what you said, my hand is raised waaaaaay up.

I would not recommend that you change the frame rate of the original movie. As an analogy, when you do sample rate conversion, or .aiff --> .mp3 conversion, something gets lost or changed in the process. Same with "interperting" video from one format to another. It won't be an accurate-enough representation. Your best bet is always to maintain the frame rate of the original video. Otherwise you're potentially asking for sync problems down the line.

In fact, it would be best for everyone involved (yourself as well as the editor) if they sent you a QT version of the movie rendered in Final Cut or whatever software they're using for editing, to YOUR specifications. When I do a film project I make a point of speaking with the editor and giving them my technical criteria. It is:

1• QT movie (their choice of compression)

2• must be a full frame render

3• 640x480 picture size

4• standard academy leader before first picture

5• timecode burn at their session frame rate which starts on the first frame of the academy leader (usually 00:59:50:00)

6• timecode for first picture @ 01:00:00:00 or greater

7• timecode burn placed as low onto picture as possible, or, if letterbox format, timecode burn placed in lower black field

If they're production is at 23.98, get them to render you a 23.98 copy and again, don't worry about Logic's frame rate setting. Just set it to 24 and get on with the work at hand. IMO, you will encounter more problems by getting involved in pull-ups and pull-downs and differing frame rates than is worth the trouble.

Oh tell me about it, educating people on the difference between DVDROMs and Video DVDs or DVD-Rs is a bit of a nightmare.

I'd steer away from digitizing as well, certainly it's my experience that this is far from a safe system, especially if there's no way of double checking whether any frames have been dropped. If they send you a DVD I'd use handbrake (freeware) which is surprisingly stable: http://handbrake.m0k.org/

I recently ripped over two hours of footage and it didn't drop a single frame.

Best of luck, and I'm sure it won't be long before logic sorts out this glaring oversight....... alongside other things, pleeeeeeease!

Whilst we're at it, can I also promote a fantastic tool that I use to communicate between various members of any production I've worked on over the last four years; music editors, supervisors, editors, directors, producers etc:

http://spottingnotes.com

Which was coded by a friend of mine and enables me to work on films based in LA from London without the production feeling like it's missing out on not having me in the same city.

I've heard good things about handbrake also. And in putting together a scoring reel I used a program called "Cinematize" to xfer DVD-->QT. Having said that, I've never used either program to create a work print to score to.

Christian, you can repeat yourself on the 23.98 oversight as many times and as loudly as you wish to and I'll back you up 1000% FWIW; for despite the fact that you can score without that frame rate option, wouldn't life be soooooo much easier with it (he asked rhetorically)?

Cheers!

-=iS=-

Thanks for your insights on this iS.

It would seem that the rule of thumb is to be SURE that you're getting 23.98 video with included timecode overlay burn. Otherwise, it's impossible to spot to it accurately. Besides that, everything else is really irrelevant?