Audio 24 to 25 pullup in Protools

[gato sapato]

So I am finishing a mix for a short-film, quicktime dv pal 24fps (shot on REDONE, 24), recorded sound at 24 - and now I am asked to deliver a 25fps version for DVD, when I have a couple of hours left to deadline (typical, I guess).

I am mixing in PT HD and was told it involves slowing down audio and lowering the pitch - both of these things mean processing and I am not sure there is a (quality) difference if I do it with the basic available plug.ins or if there are appropriate plugins that will just process it all at once.

Any suggestions ?

[danijel]

For a quick help - speed up your sound to 96% ( = 24/25 = 0.96) of its original length. You can do this with or without correcting the pitch to sound more like the original. Good pitch correction is done with many softwares - check the Geo's post corner.

[sonnykeyes]

Originally Posted by gato sapato

So I am finishing a mix for a short-film, quicktime dv pal 24fps (shot on REDONE, 24), recorded sound at 24 - and now I am asked to deliver a 25fps version for DVD, when I have a couple of hours left to deadline (typical, I guess).

I am mixing in PT HD and was told it involves slowing down audio and lowering the pitch - both of these things mean processing and I am not sure there is a (quality) difference if I do it with the basic available plug.ins or if there are appropriate plugins that will just process it all at once.

Any suggestions ?

Call me crazy, but last time I looked, a second took up an elapsed time of one second, no matter how many picture frames it got cut into. Would they really want to speed up or slow down their show for DVD? Just asking.

Sonny Keyes
Ricochet Audio
Toronto

[ErikG]

Sonny, a second is not always a second. TV and fillm transfers are a pretty complex subject.

You to could (should) read up on Geos corner as suggested by Danjiel if you want to know more.
If you are serious about working with sound post you really need to understand this, otherwise you will eventually get burned.

[sonnykeyes]

Originally Posted by ErikG

Sonny, a second is not always a second. TV and fillm transfers are a pretty complex subject.

Thanks Erik, will do. My longest productions are :60, so it hasn't come up, but as you say, I should read up on this stuff. As I said, just asking!

Sonny Keyes
Ricochet Audio
Toronto

[gato sapato]

Thanks, I did not have the time to dive in Georgia´s encyclopedic posts (wonderful stuff, by the way).

I used TimeShift (PT 8) and processed the mix increasing the speed by 4% - which is what you meant isn´t Danjel? When I take out 4% of the speed I am left with 96% of it. Did not mess around with Pitch as I am not sure about PT´s original plugins.

[musikwerks]

Speed up the finished mix by 4.1%. You can adjust pitch if you want to but it's not always a big deal.

[Branko]

The fastest way is to create a new PT session, then import the final track from your mix session, applying the SR convert option. Choose "Film to PAL" and it will automatically apply varispeed. You can process it with some high quality pitch shifting plugin, like Elastique or X-form (if you have enough time to wait for it to finish the job)

[apple-q]

Originally Posted by danijel

For a quick help - speed up your sound to 96% ( = 24/25 = 0.96) of its original length. You can do this with or without correcting the pitch to sound more like the original. Good pitch correction is done with many softwares - check the Geo's post corner.

BEWARE! The ratio from 24 to 25 is not 0.96!

It´s 4.16666666666667%. It´s 4% the other way (25 to 24)

Make sure you use a tool that recognzes a lot of fractions otherwise you will get roundng errors and your result will drift out of sync depending on it´s length and the accuracy of the plug-in.

[gato sapato]

Branko - What do you mean by the SR convert option ? And the "film to PAL" option ?
I did open a new session, imported the L/R mix and then someone suggested I changed the session settings to 25fps and (below in the same window, cmd-2) I noticed film/video settings. However it did not seem to apply any processing and also, because I did not have the sped-up dvd video I could not confirm if sound was good or not.

So I did it with Timeshift.

[danijel]

Originally Posted by apple-q

BEWARE! The ratio from 24 to 25 is not 0.96!

It´s 4.16666666666667%. It´s 4% the other way (25 to 24)

apple-q, come down, and stop giving advice on things you're clueless about.

When going from PAL (25fps) to Film (24fps), time slows down by a ratio of 25/24 = 1.041666, so the sound comes to 104.1666% of its original length.
When going from Film to PAL, time speeds up by a ratio of 24/25 = 0.96, so the sound comes to 96% od its original length.

And please, before you respond, do your homework.

[danijel]

Originally Posted by gato sapato

Branko - What do you mean by the SR convert option ? And the "film to PAL" option ?

In the "Import Audio" dialog, check the "Apply SRC" checkbox, and look at the settings below.

[musikwerks]

Not trying to be an ass here, but Danjiel, when you play out from Avid Meida Composer from 24fps to 25, it gives you the value of 4.1%.... not an even 4.0%.

Over the course of a feature film that 0.1% could add up to a significant amount of drift if not accounted for.

[danijel]

Originally Posted by musikwerks

Not trying to be an ass here, but Danjiel, when you play out from Avid Meida Composer from 24fps to 25, it gives you the value of 4.1%.... not an even 4.0%.

Not at all, I only have a problem with people yelling.

Your Avid is probably showing the speed-up percentage, not the length difference.

When you play a sound at a speed that is 104.166% of the original, it will last for 96% of the duration of the original.
(100/104.1666 = 96/100)

So maybe the Avid is truncating 4.1666 to 4.1% or you're looking at numbers that involve 23.976 to 25, not true film speed.

[apple-q]

Originally Posted by danijel

apple-q, come down, and stop giving advice on things you're clueless about.

When going from PAL (25fps) to Film (24fps), time slows down by a ratio of 25/24 = 1.041666, so the sound comes to 104.1666% of its original length.
When going from Film to PAL, time speeds up by a ratio of 24/25 = 0.96, so the sound comes to 96% od its original length.

And please, before you respond, do your homework.

Change in % = (Target-Original)/Original*100

Going from 24 (original) to 25 (target) is

(25-24)/24*100=1/24*100=4.1666666667% speed-up (faster)

or 24*1.041666666666667=25

104.16666667% refers to the speed change. The OP wrote that he was going to "slow down" the audio from 24 to 25. 24 to 25 is speeding up to 104.16666667% of the original or 4.16666667% faster than the original 24fps film.

These are the common numbers you find in the AVID because it refers to speed. I should have mentioned that in my initial posting.

(see page 8 of the "Sync & Surround Concepts" pdf in the protools documentation folder)

Have a nice day!

[musikwerks]

Danjiel, this was for feature film edits, 24fps. We would regularly conform sequences from the rushes to be used for test audience screenings, played out to 25 fps Digi Beta and then transferred to 35mm film for the screenings.

[danijel]

Originally Posted by apple-q

104.16666667% refers to the speed change. The OP wrote that he was going to "slow down" the audio from 24 to 25. 24 to 25 is speeding up to 104.16666667% of the original or 4.16666667% faster than the original 24fps film.

These are the common numbers you find in the AVID because it refers to speed. I should have mentioned that in my initial posting.

Now, that is correct. I don't use AVID stuff for this, so I think in length, rather than speed. I just got bumped by your BEWARE sign on my perfectly valid post, and than your numbers without units. Anyway, I did confuse the OP, because he was using TimeShift -

Originally Posted by gato sapato

I used TimeShift (PT 8) and processed the mix increasing the speed by 4% - which is what you meant isn´t Danjel? When I take out 4% of the speed I am left with 96% of it.

Gato, sorry, I missed this post - in TimeShift, the speed should have been 104.17% (two decimals only).... So the legth comes to 96% of the original. I hope everything turned out OK.

Originally Posted by musikwerks

Danjiel, this was for feature film edits, 24fps.

OK, AVID has rounded it then, at least in the manual, but they probably still respect the fractions in calculations.... Most people use the figure 4.1% in speech, just like many say they work at 24fps, when they actually work at 23.976fps. Within ProTools SRC they call it 4.1667% pull-up.

[gato sapato]

hey Danijel - no worries.

Yes, I did that, except not with the decimals .17%. But as I said, I need to check it with the corresponding image to see if it is ok.

(And next time I´ll know a lot more about it...)