mixing 25p and 24 fps for filmout?

[Henk van den Doel]

Ok, so we have our first job coming up that is not only going on television as a commercial, but also out to 35 mm to play in cinemas! Great of course, however we have some questions and uncertainties.

We live in PAL-land here. The concept we have in mind now, will involve some greenscreen work that still needs to be shot. We were thinking of shooting that 24 fps initially. However we wish to use some shots in the background we already have in stock, but these were shot at 25 and 100fps. Are these shots even usable at all? Can we conform the 25P footage to 24fps, shoot the rest at 24 and we are good to go? Or aren't things that easy?
Or shoot everything at 25P, finish the project in 25P and later conform to 24 for the filmout?

If anyone can give us some insight on what we are about to encounter on possible problems, that would be greatly appreciated as well..

Thanks in advance!

 

[Ido Karilla]

I think that it all depends on if you have synced sound in the 25fps base footage. If not, conforming to 24, or output from REDCINE at 24, should work all the way to the big screen.

 

[Vigen Vartanov]

Only one problem that you will have is sound. If you have lips in
frame and some body speaks in 25fps shoot , when you will go to 24 you will lose 1 frame in every second ,
sow in 2 minutes your sound will be sync with video .
But it is old problem , and there is sow many solutions and plugins for it . Check google .
You will found many solutions. Also you can just speed up sound ,
change it to 24 fps .

 

[Hans von Sonntag]

I've done that many times. Shooting 25 fps for a 24fps timeline is creating a non-visible slowmotion. Slowing down synced sound from 25 to 24 fps on the other hand does make a big difference. What to do?

For a short commercial you can re-sync the 25 fps sound to the 25 fps shots in the now longer 24 fps timeline. If the dialogue is not too long it will work nicely. This way leaves the sound untouched. Otherwise there are many tools out there which bring back the tune to its original level when slowed down from 25 fps to 24 fps.

Hans

 

[Henk van den Doel]

Cool, thanks for the advice guys.

 

[Dominic Jones]

The usual way to do this (it's done all the time for DVD transfers etc) is to slow the sound to match sync and then pitch-shift it up by 4% to regain correct pitch.

One thing that's worth mentioning is that you can, of course, do this either way - shoot 24fps and convert to 25, or shoot 25fps and convert to 24... The question is, which do you (or your clients) regard as the primary output? I would then shoot at the native framerate for that version, and do the conversion to the secondary, although done well they should both come out looking ans sounding virtually indistinguishable to the human eye and ear, although they will, of course, be different lengths - perhaps an issue for broadcast as a commercial, in which case it may make sense to shoot @ 25fps?

Hope that helps, and congratulations on getting the project!...
Dom.

 

[Cail Young]

Given this is short-form, the "best" solution is to shoot at 25fps.

Cut your broadcast version together at 25fps.

Then, when you online for your 24fps theatrical version, conform all the source material to 24fps and adjust the edit so it runs to the same length. You will need to adjust audio pitch/speed to sync.

On a longform you wouldn't worry about adjusting the edit - but given you're probably required to deliver a specific time on each framerate you'll need to tweak the edit slightly.