Editing 18fps in NLEs
Posted 19 July 2010 - 12:24 AM
Can I shoot super 8mm film at 18fps, then have it scanned and edit it in an NLE without any sort of work flow that involves frame blending?
From what I understand, the frame-by-frame scanning equipment like the Moviestuff gear handles 18fps well by adding some exotic pulldown. Would I import this to my NLE as 29.97 or 23.976, or 24? Then, would I have to be careful about which frames I cut on?
To aviod this, would it be better to have my 18fps footage scanned at 24p, edit it in my NLE at 24p and then do the pulldown on output? What would I use to putput a 24p timeline to 18fps media files that can play on computers? If I don't mind the slight slow motion, can I output the 24p timeline to 15fps computer media and keep all frames. I mean, can I achieve 15fps output with a method that doesen't cut out frames but instead simply uses all the frames I shot but play them back at 15fps by extending my video?
Also, is it correct that rank systems aren't set up for 18fps? I ask because I want to shoot with negative stock and the maker of Moviestuff gear say's it can't handle negatives (although I've found one house that claims it has found a workaround for using the Moviestuff gear for negative film).
Again, to be able to use rank transfers, could I have my 18fps footage scanned at 24p, edit it in my NLE at 24p and then do the pulldown on output?
Posted 25 July 2010 - 05:59 PM
Posted 26 July 2010 - 07:41 AM
But for making compatible files with DVD or Blu-ray you have to use the standard speeds (24, 25, 29,97) so unavoidably you have to duplicate frames in the end...
Posted 26 July 2010 - 10:44 AM
Posted 26 July 2010 - 11:06 AM
Posted 01 August 2010 - 06:36 AM
Posted 01 August 2010 - 07:46 AM
Posted 02 August 2010 - 06:40 AM
Later, if you need 25fps for DVD for expample, you can do this in post. It is important to have the original film frames on the digital master file.
The problem with NLE's is the fact that it all happens on the background. It is better to have full control over the frame rate conversion.
Play speed is one thing, frame rate is another thing.
Assuming a one film frame = one digital frame file, then play speed is just a number, telling the computer how many frames/sec it must display. Easy enough to change this with VirtualDub for example.
Changing the frame rate is only needed if one wants to make a copy of the file in a standard format that needs another frame rate like standard PAL (25fps) for example. The problem is always the same: we must change the frame rate without changing the original play speed.
There are three ways to do this:
1) adding duplicate files, this means some frames will be showed twice.
2) blending: the computer will create intermediate files with info from the previous and the next file, but only on parts with high motion. The more motion, the more blending.
3) interpolation: the computer will draw complete new frames, based on motion analysis. Only a few original frames will be left over.
It is possible to convert any play speed to any frame rate, and it can be all done with Avisynth. A correct prepared 18-25fps clip will not be changed by your NLE any more. The NLE will accept it as a standard 25fps file. If you render it to Mpeg2 (DVD) it might add interlacing, but you can force it to render progressive.
On high motion scenes, I use frame blending. On low motion scenes, I use interpolation. See my examples on Vimeo.
Because I always keep my frame accurate progressive masters on portable HD's and on several backup computers, I can always change them later to another play speed/frame rate. (HD for example)
Hope this helps,