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converting 29.97 to 24p

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adeeb oberoi
converting 29.97 to 24p
on Aug 31, 2009 at 4:51:20 am

HELP!!! I made a short animation to be played in the cineams. I did it on 29.97 frames and squared pixels. The cinemas its playing are digital. I was shoked, they did a terible convertion, the animation staggers and the animation is not smooth. My guess is they made it 24 frames.

I know something went wrong in the convertion so I am trying to fix this myself. Tried the FPS converter form A. Kramer, but doesnt work well in this case, it deforms the 3d logo animation I did in Zaxwerks.

I know they just changed the comp settings to 24 frames, I tried that and gives the same staggering effect. But when I go to INTERPRET FOOTAGE and then go to confirm to frame rate and type 23.976, it plays fine.

Please advice if this is a good solution. My client is paying tons of money to the cinemas, to much to see the animation ruined.

Looking forward to hearing from you,

Adeeb Oberoi



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Kevin Camp
Re: converting 29.97 to 24p
on Aug 31, 2009 at 1:27:19 pm

hi adeeb,

using interpret footage and setting the frame rate to 23.976 is the easiest way to get the smoothest motion, but it will be slowing the footage down by 20%... which is fine as long as that doesn't cause problems with timing for audio or some other element that won't be slowed down too.

if timing is important, or you (or the client) doesn't want to slow the footage, then it may be a little work to get the project to 23.976....

if all the elements were keyframed within after effect (and not pre-rendered), then you could just change the framerate in the comp settings. how ever if the comps contained 30fps footage or pre-rendered animations, then you'd need to change/conform the frame rates of those to 23.976 too.

for pre-rendered footage that may be as easy as changing the settings in those comps (or project files in another application), re-rendering them and getting those back into your ae project.

for other footage you can try andrew's frc technique, however, if it is interlaced 29.97 footage, you can spend a little more time and get better results. here's a technique i've used:
  1. in the interpret footage settings, make sure ae is set to separate fields (propper field order) and 'preserve edges' is enabled.
  2. drop that into a new comp, change the comp's framerate to 59.94fps and then choose layer>time>time stretch and set it to 400% and enable frame blending (pixel interpolation). render that footage out and import back into ae. this will essentially make the footage 120fps but at half speed slow-mo. 120 is a good number because is is evenly divisible by 24.
  3. take that render and drop it into a new comp, change the frame rate of that comp to 23.976, and do a time stretch of 50% and do a ram preview and see how it looks. if the movement seems a little too tight (like not enough motino blur), try enabling frame blending (frame mix) and ram preview. if that doesn't smooth it out enough, disable time stretch (set back to 100%) and add timewarp, set it to 200 and enable motion blur (within timewarp) and set as needed to smooth the motion.

you could use the same technique on your final render if you have too many footage layers to make changing the comp to 23.976 feasible. if your final render was 29.97 progressive, then you should break up step 2 from above into 2 steps and you may want to try using timewarp instead of time stretch to get the added tuning features, as i've found that time stretch often isn't as good with progressive cg animations...

so, in step 2, using timewarp you can leave the comp at 29.97, set the speed to 50 and tune as needed to get good interpolation, then render and import that back in. then do it again to that rendered footage. now add that last render to the new comp in step 3, but this time you'll need to set time stretch to 400%, or set timewarp to 25% to get it back to the timing correct.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW


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adeeb oberoi
Re: converting 29.97 to 24p
on Aug 31, 2009 at 3:21:29 pm

Thanks so much for all the inf. I need to take a moment to study this.

For now I think I will go with the interpret footage (conform to frame rate). Its toooo much work to back into the AE project and re-render.

Questions:

1. When not using video footage, just AE animations. exported as quicktime. While setting the compostion settings, Is this always progresive if I select squared pixels? Doest the preset HDV/HDTV 720 29.97 have anything to do with anything?

2.In iterpret footage should I leave Pixel aspect ratio to : Squared pixels?

3. After convertion method above, What happens if I go to time stretch and put 80% to compensate the 20% of slowdown.

Thanks again,

Adeeb


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adeeb oberoi
Re: converting 29.97 to 24p
on Aug 31, 2009 at 3:23:18 pm

OOOh, and how do I know if my animation is 29.97 progresive or interlaced?

Regards,

Adeeb


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Kevin Camp
Re: converting 29.97 to 24p
on Aug 31, 2009 at 4:09:41 pm

the answer to your first question is that the comp settings have nothing to do with interlacing... if you want a field render (interlaced render) you'll just need to enable that option in the render settings when you render by setting the fields render to a particular order (upper/lower). by default, ae should be set to render progressive frames.

in ther interpret footage setting the pixel aspect ratio should be set to what the pixel aspect ratio is... usually ae gets it correct, but if you know that the footage is not what ae thinks, then you should correct it... so, if you know that it is square, and ae thinks that it is not, then you should set it as square. or if you can tell that the image doesn't look right, like it's stretched in one way or another, then you can try to correct that with the pixel aspect setting.

for your third question, if you try to speed the footage back up, you will probably end up with a similar stuttery motion that you had before.. this is due to dropping every fifth frame to conform the 29.97 to 23.976.

to answer your last question, as mentioned above, if you set your render settings to field render then you would have an interlaced render, otherwise it should be progressive. also, if you make sure that ae is not separating fields (in the interpret footage settings) and step through it frame by frame, in frames that have a moving object you will see horizontal lines on the edges. it will be most noticeable on frames with faster motion and higher contrast edges.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW


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adeeb oberoi
Re: converting 29.97 to 24p
on Aug 31, 2009 at 10:44:11 pm

Thank you very much, this is very clear.

Maybe its me but when I render I do not see the option UPPER/LOWER, I always render quicktime movies.

I will always render progressive probably but would still like to know where these settings are.

Kind regards

Adeeb
PS: Thanks so much, my animaton plays smooth at 24 frames, I just had to do the fade in a little later to make up for the extra secs beause of the convertion.


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Kevin Camp
Re: converting 29.97 to 24p
on Sep 2, 2009 at 2:42:04 pm

[adeeb oberoi] "when I render I do not see the option UPPER/LOWER"

when you send the comp to the render queue (using composition>add to render queue or composition>make movie), click the render settings. there you can set the field render option, along with other render options. the output module options contain the options for format and codec (like quicktime animation, etc).

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW


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adeeb oberoi
Re: converting 29.97 to 24p
on Sep 2, 2009 at 2:46:47 pm

Got it, thx.... Normally I dont even change these settings, just leave it to best settings...(standard settings I guess).

Buit its great to know. Maybe for future projects.

Thanks again,

Adeeb Oberoi


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Chris Hart
Re: converting 29.97 to 24p
on Jun 1, 2010 at 6:16:13 am

I'm in the same boat, right now rendering a 23.976 version of the 29.97 created w/ timestretch/timewarp. Long render due to motion blur. But I want to mention: these days we do rolls for hd 24p projects. With the monitor refresh rate of 60 or greater, there is no way to avoid flicker on a 24p project with whitish credits rolling up a blackish screen from ae. You can blur, but the flicker will be there. If you don't use an integer # of pixels per frame (and that expression should say pixels/frame, not pixels/sec) the flicker is much worse, but it will be there because the scan lines are offset from the 23.976 motion (as opposed to coinciding exactly with the 29.97 motion, assuming an even # of pixels/frame).

Or am I wrong?

Chris Hart
http://www.chrishartedits.com
chrishartedits@gmail.com


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