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Converting animation & audio from 24 fps to 25 fps
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John, reading your post I thought I’d written it. We’re in perfect agreement.
In fact everyone might agree with us. There’s an ambiguity in the word “convert” which might be what prolonged this thread. See my comments just above. -
Well by convert I meant I want to change the animation from 24fps to 25fps without changing the length of the episode, and try to keep it synced with the sound as much as possible. We can’t lose the seconds from the length as it needs to be 10 minutes exactly for broadcast.
Thanks for all the advice though guys, it’s really helping me get my head around the problem. We’ve done a patch job in after effects but if there’s a better option I’d like to know what it is!
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[Dennis Couzin] “What I mean by converting 24 fps material to 25 fps material is adding an extra frame to the original so there are now 25 frames for each second. Frame rate conversion, in my book, means conversion without changing length (running time). “
But this process will not passing BBC standards for PAL.
” How does one go about declaring 24p digital video 25p digital video? Who knows how to go into a header, or a wrapper, and change ’24’ to ’25’? Maybe many more numbers need to be changed.”
This is called a conform and is done in Cinema tools and a dozen other apps, including FCP which as a Conform 25 to 24 under the tools menu.
the conform which does slow the material by 4% has been the accepted process for PAL countries since the dawn of transmission, There are hardware tools from companies like Snell and Harris that can do the time base conversion without mucking up the audio, they are by their nature expensive.
gary adcock
Studio37
HD & Film Consultation
Post and Production WorkflowsInside look at the IoHD
https://library.creativecow.net/articles/adcock_gary/AJAIOHD.php -
Riana, thanks for the clarifying. Conversion without changing length was how I understood you in the first place, and what I meant in “of course you can convert from 24 fps to 25 fps. The question is whether you can stomach the result.”
What is the style of animation? For some styles of animation, frame interpolation can be nearly perfect. You can try Compressor’s rate conversion with its “best” setting. Who has a better interpolator?
If that produces a mess, your best hope is insertion of one frame per second into the original 24, but I previously overlooked a superior method. If your video is 24p then it can also be reckoned as 48p with 24 identical pairs of full fields. Now instead of inserting one new frame, which is a pair of full fields, into the 48 fields, it will be much less noticeable to insert one field at one point and another field approximately half second later. (The approximateness is useful to hide the intrusions.) Then you have created a 50p animation and you must keep it at 50p. You can make a trial of a few second of this by hand. FCP seems incapable of handling separate fields, but Avid can do it.
For example:
original frame 1 for 1/50 sec
original frame 1 for 1/50 sec
original frame 1 for 1/50 sec
original frame 2 for 1/50 sec
original frame 2 for 1/50 sec
original frame 3 for 1/50 sec
original frame 3 for 1/50 sec
original frame 4 for 1/50 sec
original frame 4 for 1/50 sec
original frame 5 for 1/50 sec
original frame 5 for 1/50 sec
original frame 6 for 1/50 sec
original frame 6 for 1/50 sec
original frame 7 for 1/50 sec
original frame 7 for 1/50 sec
original frame 8 for 1/50 sec
original frame 8 for 1/50 sec
original frame 9 for 1/50 sec
original frame 9 for 1/50 sec
original frame 10 for 1/50 sec
original frame 10 for 1/50 sec
original frame 11 for 1/50 sec
original frame 11 for 1/50 sec
original frame 12 for 1/50 sec
original frame 12 for 1/50 sec
original frame 13 for 1/50 sec
original frame 13 for 1/50 sec
original frame 13 for 1/50 sec
original frame 14 for 1/50 sec
original frame 14 for 1/50 sec
original frame 15 for 1/50 sec
original frame 15 for 1/50 sec
etc. -
Gary, thanks for the info on conforming.
Riana McKeith’s latest post makes it clear that converting, not conforming, is what is needed. -
[Dennis Couzin] “Gary, thanks for the info on conforming.
Riana McKeith’s latest post makes it clear that converting, not conforming, is what is needed.”Dennis
I can assure you that if you run some conversion that adds frames to pad the timing, it most likely will cause issues with the broadcasters.
I guess the question I have is, if this is animation, why even screw with this, have the render done at 25fps instead of 24 and solve all of these issues, as that is by far the easiest way to solve this issue.
gary adcock
Studio37
HD & Film Consultation
Post and Production WorkflowsInside look at the IoHD
https://library.creativecow.net/articles/adcock_gary/AJAIOHD.php -
Gary,
I think your advice:
“if this is animation, why even screw with this, have the render done at 25fps”
is almost the same as mine:
“For some styles of animation, frame interpolation can be nearly perfect. You can try Compressor’s rate conversion with its ‘best’ setting.”The question is whether FCP’s 24->25 render will look as good as Compressor’s or some other interpolation program’s. Is FCP’s method of 24->25 rendering documented somewhere? Is Compressor’s “optical flow technology” documented somewhere? I think the most effective 24->25 “render” for an animation will use original frame 1 and then create 24 new frames (1.96, 2.92, … 24.04) before using original frame 25, etc. That’s a lot of interpolation, so it had better be good.
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[Dennis Couzin] “”if this is animation, why even screw with this, have the render done at 25fps” is almost the same as mine: “For some styles of animation, frame interpolation can be nearly perfect. You can try Compressor’s rate conversion with its ‘best’ setting.”
“No. Compressor is useless for frame conversions I did testing with the BBC that confirmed that especially useless for timebase conversions due to its inability to understand where and when to handle data correctly. Compressor was originally designed to be the rendering tool to create Mpeg files for DVDSP. It does a really poor job at handling broadcast formats. Shake or AE on the other hand do quite well at timebase conversions.
What I was referring to above if it is truly animation, why is the ORIGINAL ANIMATION not being rendered out of the application that created it at 25fps instead of 24fps.
Dennis – how much of this do you do? IMHO it sounds as if you are speculating on what to do rather than working from actual knowledge and experience.
gary adcock
Studio37
HD & Film Consultation
Post and Production WorkflowsInside look at the IoHD
https://library.creativecow.net/articles/adcock_gary/AJAIOHD.php -
Gary, you need to debate your Compressor finding with Ken Stone who wrote in “Converting Frame Rates in Compressor” just four months ago: “Why use Compressor if FCP can do the job? Because, while FCP can do it with little hassle, the truth is, that Compressor can do a much better job of converting frame rates using Frame Controls which is based on Shake’s Optical Flow technology. Using Compressor does take extra work, so if you need a quick way to work with different frame rates in the timeline, and it doesn’t matter if the footage is a little choppy, use FCP.”
My background is in film. Some of my suggestions to Riana McKeith are based on the experimental results described under “fancy slow” in “Notes on Optical Printer Technique” (https://sites.google.com/site/cinetechinfo/). Frame rate conversion is a terrible problem for film precisely because there is no film method for image interpolation. Digital video can do this. It is obvious that the best way to convert 24 fps to 25 fps is to follow frame 1 by frame 1.96 (which is 96% of the way between frame 1 and frame 2), then frame 2.92, then frame 3.88, … then frame 24.04, then frame 25, then frame 25.96, etc. All these decimal denoted frames are interpolations. How the interpolating is to be done is non-trivial, and some methods will be superior to others. It’s also obvious that some styles of animation are easier to interpolate than live action is. Other styles of animation might not be.
You write: “…if it is truly animation, why is the ORIGINAL ANIMATION not being rendered out of the application that created it at 25fps instead of 24fps?” Come on, not every animation is created in an animation application with choice of render out framerates. An animation can be made from 24 separately made drawings (or other pictures) per second. Then, the problem Riana McKeith posted can arise.
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What I described is merely 2:2:2:2:2:2:2:2:2:2:2:3 pulldown as described in the Wikipedia article on Telecine (with the 3 at the other end). That article is not hopeful on that sequence. Perhaps some randomization in the length of the sequence would help.
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