Frame rate conversion, judder and Timewarp crashing

[Kevin Camp]

there’s a few other questions too…

you said you have 29.97 fps footage.

dave is asking if the 29.97 footage is actually 24p with a pulldown (if so you will need to remove the pulldown, but then it should move right in to the 24p project without any further conversion)…

however, if the footage is actually 29.97, then there is a question of is it 29.97 progressive or interlaced?

if it is interlaced, then you need to make sure that ae is properly separating fields (select footage in project window, choose file>interpret footage>main, set field order). since you want to go to progressive, i’d also click the preserve edges option. then i’d drop that into a comp with the same frame rate as the destination (you said 24p, i assume 23.976 fps). then i’d try enabling frame blending (frame mix, not pixel motion), this will blend neighboring frames and the field data from the other field that is being lost to help smooth things out. do a ram preview and see if that looks any better.

if it is 29.97 progressive, then make sure that the footage is interpretted that way. then i’d try a similar approach with frame blending (frame mix) and se how that looks. it won’t be quite as smooth since you don’t have samples at 1/60 of a second, but since the footage is already progressive, it may look a little cleaner.

ae’s standard tools aren’t the greatest for doing this and there are other plugins that should do a better job (i don’t care much for timewarp, since if the footage is interlaced, it will ignore the other field data when trying to modify the frame rate… you end up having to convert you footage to 59.94 progressive then trying timewarp to get the best results). you mentioned rsmb, revision has 2 other effects that may help you out here, fields kit, which will give you better deinterlacing than ae’s, and twixtor, which will give you the frame rate conversion. you might look into both of those if you do this often enough.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW

[Adam Mercado]

Hi Dave

Yes I am very familiar with the term 3:2 Pulldown.

Unfortunately in this case it does not apply.

The media in question was created in a 3D animation app. It was rendered (I assume, as it was supplied to me this way) at 29.97 at 720×480, but I have since scaled it up to 960×720 to fit in my show. I don’t think it is interlaced, AE does not recognize it as such, and none of the tell-tale signs are there.

So no pull down.

Are you familiar with the Andrew Kramer frame rate conversion technique. If not you should. Its very useful. It uses timewarp to pixel smooth the frames. In theory it should work well, but on my MacPro it fails badly.

Thanks
mm66

Adam Mercado
Influxx Media Production
Motion Graphics & Video Post Production
Fullerton, CA

[Adam Mercado]

Thanks Kevin, if you read my response to Dave you will see this is progressive and true 29.97 3D animation.

All interpretations are correct in AE. I have fields kit but it did not appear to make any difference to the smoothness of my render. Twixtor is out of my budget, and I have heard other reliable comments about Timewarp. Figuring it did a close enough approximation as Twixtor I decided to stick with it.

Is it typically slow buggy and crash prone?

cheers
mm66

Adam Mercado
Influxx Media Production
Motion Graphics & Video Post Production
Fullerton, CA

[Kevin Camp]

since you know the footage is not interlaced, my biggest issue with timewarp (losing the opposite field data) won’t be a problem for you, nor would you need to use fields kit or any other deinterlacing steps.

timewarp with pixel motion on is slow, and interpolated frames will not look as good as original frames, particularly for 3d rendered footage. as far as crashing, i haven’t noticed the problem, but you might try disabling multiprocessing to see if that cures the crashes.

the best option would be to get the 3d rendered at 24p. another option may be to interpret the 3d footage as 24p, this will keep all the image quality but slow the animation down by 20%, but if timing isn’t important, then this may work for you.

you could try adding rsmb, render that out and then try timewarp on the rsmb effected footage. rsmb may smooth things out enough that the interpolated frames that timewarp creates will look more natural. but again, don’t expect interpolated frames to look as good as the originals.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW

[Adam Mercado]

Hi Dave

So it comes back to Twixtor. I was hoping this would not be the case, but I feel you are right. Spent all night rendering 5 of these clips using Timewarp, and the stuttering is still very much present. I was really expecting The Kramer Technique to work considering how involved it is compared to just rendering out at 24fps. The difference is negligible.

As far as upscaling, this is not so much an issue. The upscale is a bit soft but within the clients satisfaction margins. I did explain to them the pitfalls of upscaling and they are okay with that. There is not budget for InstantHD. The stutter and judder is very bad though, my main concern.

The 4:3 clips are sitting centered over a textured BG in the 1280×720 frame.

Thanks again for the input.

cheers
mm66

Adam Mercado
Influxx Media Production
Motion Graphics & Video Post Production
Fullerton, CA

[Adam Mercado]

thanks for the tips Kevin. I am trying RSMP post-Timewarp, but I will try pre-Timewarp too and see how that looks.

Slow – you aint kidding. Like molases, and for a MARGINAL improvement. Suck!

The slight degradation of the image is not too bothersome, its the horrible judder that really troubles me.

As far as getting these re-rendered, geez i’d love that. It took me 2 months just to get a disk of AVI’s after they tried to supply me with MPEGs. So i’m thinking no way. Gah! clients!!!

cheers
mm66

Adam Mercado
Influxx Media Production
Motion Graphics & Video Post Production
Fullerton, CA