Frame rate math? (29.97 to 25fps)

F

fishkarma

New member
Hey, hope alls well in the world of Home Rec?

I'm having a few issues with math...
Basically I have an animator that has been supplying me with 29.97fps films to which I have sync'd my music to (this is a college project by the way) very tightly. Basically the different charracters are birds and people, when ever a bird somes on scene I add a harmoney line, same for people.
So basically it has to be very tightly sync'd or it just sounds weird

Naturally to make my life difficult I've been resupplied with a 25fps final animation which no longer syncs up as she has droped 4.97 frames a second (is this how film works?)

I can't really figure out whats going on any more with these frame rates (I've never had the misfortune of having this happen to me before) and want to figure it out. I've tried several different options and read several options on the net for my scenario but when I time compress/expand it just doesnt sync up.

Can someone please explain frame rates to me properly and the time decrease/increase in the conversion from 29.97 to 25fps. Preferably so that if I ever have to deal with it again I can figure out what I need to do myself...

Sorry I'm posting this in the PT forum as theres no film forum.

Peace
-Josh
 
This might not be the easiest place to find an answer to your question.

Maybe you can ask for a 29 frame final version like you had first composed to.

Doesn't the timeline stay the same though? The movie is not shorter because of less frames. Can't the parts stay in the same place and still work with the picture? That much of a time difference can't be that offsetting with the music, or can it?

Sorry asking more questions than I'm answering but maybe I will have given an idea.

Good Luck, Eric
 
is the final video being released in PAL format? Does the animator work abroad with you...I just noticed you were in Ireland

have you tried adjusting the timecode rate in the session setup window?
 
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No such luck,
Their final piece has to be 25fps and hence they won't give me/don't have time to give me a 29.97 animation. The movie definatly changed length, I checked that first. (and it was a 25fps version of the same animation).
As for the time offset it wouldn't be too important if the music didn't require such tight syncing. You get this weird visual/aural stutter effect which just looks/sounds weird between the two.

Also its something I think I should learn so I don't have to freak out in a professional setting if it happens again. (though I doub't in a professional setting I'd get given several different frame rates to swap between...)

Peace
-Josh
 
Sorry Bennychico I was replying to the post above.

No they are in the same college as me theyare doing a Degree course and kept exporting using Premiers default output (as far as I know) NTSC 29.97fps

Their brief was a 25fps movie so thats what it has to be, and they have literally just driven me mad and blaming me for syncing errors even getting a lecturer involved. Either way I still want to fix this even if they don't understand the problems they've caused as the animation is very good and I feel I did a good job on the music. I would ideally like to be able to use it as part of my portfolio when I'm finished.

So yeah its supposed to be in PAL (though I don't think that its for release but either way their being difficult and has an animation lecturer that I can't really push for fixes regardless if they screwed up and don't understand.)
and yeah I'm in Ireland

Its a sad situation but I literally just want to time stretch my music (its about 2 min long) longer or shorter to re sync the thing.

Actually now that I think about it Its all done with Midi so if theres a tempo work around then it would avoid the pitch problems too... Its at 120bpm (yeah I know its a default setting)
 
I see you edited your post too...
Were both in Ireland. They just exported NTSC before and now want to change back...
Just tried the time code option it works fairly well apart from being the slightest bit off.
I'm assuming its because the default was set to 30fps as the playback speed handling the 29.97 file (This would be my fault, since I have never seen anything to do with frame rates in the session set up, as I said its a first time dealing with film...) so when I drop the time code playback from 30fps to 25 fps in reality it would be turning the 29.97 version down to 24.97? which is then off with the 25fps export?

Thanks this is great to know about especially since I haven't worked with film before. Theirs so much in PT that I have to search through still!
 
hmm...yeah, double check frame rates every time you load up a video into the session. Or anytime you're working with something that is going to be laid back to video/film.

This is a lot of thinking for me (it hurts, lol)...but you might try changing the video rate pull factor (bottom of the session setup window) to .1% up...I think :confused:
See if that fixes it. Now that you have your correct, time code rate set...you need to correct the audio sample rate via the pull up/down menus.

or actually...now that I think about it. You might be able to change the frame rate back to 29.97...change the audio pull rate to "none", then change the frame rate again to 25, and PT should do the math for you. Essentially you're re-defaulting your session to be the 29.97 you originally thought it was and may have edited to....and then reconvert it down to 25 where you need.
That might help, I hope


Also its something I think I should learn so I don't have to freak out in a professional setting if it happens again. (though I doub't in a professional setting I'd get given several different frame rates to swap between...)
Click to expand...

you'd be surprised. Of course I never have problems with NTSC/PAL conversions...but lots of times jump back and forth between 29.97, 24, 23.97, 30, etc.
 
Sorry Bennychico,
I'm not too sure where your seeing these options?
I don't see anything about video/audio pull rate. There is video sync offset in another menu but nothing in the Setup session window.

Could you tell me where to find these?

As for the film heres what really happened just in order to make sure everythings clear:
Given a 29.97 animation.
(Session setup at this point would believe it was 30fps as it wasn't changed from the default)
Everything was edited and timed to this.
She changes the animation to 25fps on her end.
Music no longer syncs.

Cheers for the help
-Josh
 
I'm guessing you have Pro Tools LE? Do you have the DV Toolkit option installed? This feature may only be in the DV Toolkit I think.

So it's still off though just a slight bit? I'm thinking an easy option might be to just time compress the rest of the audio...hopefully not changing the sonic quality too much. I know Digi's newer time-compression plugin in the audio suite menu had some presets for frame rate conversion. You might mess around with this.

I'll try and think of something else.
 
Yeah,
PTLE 8. Its not the end of the world. She can deal with it any way since its close enough. I would be interested in figureing out the math behind this in any case.

Cheers again man. Once again you have been great in responding to any problems that manage to crop up for me. Peace!
 
This wouldn't be too hard to sort out in PT HD - the options Benny was talking about are all found in HD or LE with the DV toolkit. I think the easiest thing to do would be to find an HD rig that you can get yer hands on for 30mins and follow the steps Benny set out...






on a side note, this thread hurt my head.
 
Haha, Cheers for the help lads it hurts my head too...
The main problem is finding a HD rig, theres one in college but thats now half a country away in distance and also runs HD 6 so wont open any of my LE 8 sessions which is a pain in the a**

Peace
 
What about just redo-ing the sync'ing. Move around whatever harmony to sync with the newly adjusted frames? At least for a temporary fix until you can figure out what's causing the fuss.
 
Oh god no. Theres quite a few harmony parts playing and would take forever to fix, you'd also have to put stuff on 32nd notes to get it right and its a relativly slow piece. Its a solution I've considered but I don't think it would work musically.
 
if might work too if you were able to convert your sample rate downward (or is it up?). Something like a 4% down and a .1% down. So if your original sample rate was 48kHz, maybe a file sample rate of 46,033.92Hz would work. Played back at 48kHz of course.
Time compression would sound better probably (leave the correct pitches).

I hate frame rate conversions and SMPTE math in general :mad:
 
Time compression seems like the best way to do things. Also converting sample rate in PT isn't something I've had to do before. I've always used sound forge in college for that kind of thing.
Any way she has the files now so its out of my hands for a bit.
Cheers
 
I found myself in a similar situation recently. My film student friend's final project is a short film very focused on the relationship between sound and our perception of the world in relation to it, and I ended up doing the sound for it. No dialogue, a bit of foley, a bit of live sound, and a LOT of sound design (we're talking 128+ tracks, with over 48 playing at once at some points; no minor feat considering I'm using PTLE).

Anyway, as this was his final project, he was very hyper-critical of each and every edit. At one point, he decided to change a few edits by only a few tenths of a second. I figured all I'd have to do is to cut/move the tracks as appropriate and everything should line up fine, but in the middle of moving everything I realized that I had forgotten to move the temporarily hidden/disabled tracks (as Pro Tools LE will only allow something like 32 or 48 simultaneous tracks, I was using temp bounces all over the place). Essentially, I had to re-edit all of the sounds to match them frame-by-frame to the edits he'd made. It took several extra hours to fix everything, and ended up being totally worth it, but it still sucked.

I think what I learned from it is that, until the "absolutely absolute final final final no more edits ever final" version of the video is done, it's likely not worth the time to synchronize anything on a fine/minute level. In your particular case, it sounds like the video editor didn't understand how difficult it is to change the sound to fit the video after the sound has already been recorded. As a side-note, MOST film students have absolutely no concept of audio and think of it as a mere afterthought. They assume the video aspect is infinitely more complex than "simple" audio, and don't give it the respect it deserves. Good audio is one of the main things that separates shitty film student projects from truly great film.
 
+1 steve.h
I deal with that EVERYDAY...and with both paying and non-paying clients who love to change things at the last minute. They don't seem to realize how hard it is to move 48+ tracks of audio with hundreds of regions on them. I can do it, but in the end I never feel like it still had the same feel/sound as the original mix. It's messing with perfection! Unfortunately we try and institute a "picture lock" when it's finally given to me for audio...but clients don't seem to care.
 
bennychico11 said:
+1 steve.h
I deal with that EVERYDAY...and with both paying and non-paying clients who love to change things at the last minute. They don't seem to realize how hard it is to move 48+ tracks of audio with hundreds of regions on them. I can do it, but in the end I never feel like it still had the same feel/sound as the original mix. It's messing with perfection! Unfortunately we try and institute a "picture lock" when it's finally given to me for audio...but clients don't seem to care.
Click to expand...

It's likely due to how easy it is to edit video from a practical standpoint (the creative side is quite difficult and very easy to do very poorly), compared to audio.

On a related note, I just stumbled across a great website for sound design (http://www.filmsound.org) a few minutes ago. I've already learned a lot!
 
Yeah, thats pretty much it. They just think of audio as an afterthought most of the time, though the second animator I was dealing with was great. He understood fram rates for starters and was consistant, he also understood that the edits to his animation would work best if they fell on down beats so he worked around when I could put them, if a scene needed extending or shortening to meet them then thats what he did. The only problem was he didn't have enough time on the project and the physics engine in 3D Max started going mad on him halfway through so had to make compromises to meet a deadline. Pity.

BennyChico: That picture lock idea would have been great and I would definatly try implement it the next time I do something like this, just this time round they were so freaked about getting it all done I had to work while they were working which lead to way to many hassles, I'm yet to see this animators (the frame rate problem ones) final animation as she is now citing that she cant send it across the net as she'll loose copyright (though I haven't found any such thing on rapidshare or megauploads terms of use and have recommended torrenting it to me without uploading it to a trackersite or FTP, with no reply in a week...)

steve.h: Yeah filmsound is a great website, you may also find freesound.org helpful too
 
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