best way to render/handle 25fps native aeps for 29.97 use?


#1

Hi -

I’ve noticed that the native encoding for some of the aeps here is 25 fps (for pal?)… but since all my encoding is at 29.97 fps for NTSC/video… what’s the best way to handle this?

a) change the frame rate to render to 30fps(?) in ae when rendering? that’s a choice when “make movie” is selected to render… changing render from native 25fps to something else like 30fps or 29.97 fps… what’s best? (tradeoff = slower render times/interpolated frames?)

or

b) just render in the aep’s native 25 fps and drop it into my nle (vegas) 29.97 fps timeline and not worry about it

c) other?

not sure the best approach, I don’t want jittery renders, or mixed render looks since I composite projects with multiple aep footage (eg an intro from a 25fps aep render plus video box from 29.97 standard aep render plus more…).

thx,

-k


#2

“A” option for native AE elements is the best, but if you have pre-rendered files in PAL then i suggest you “C” to try “PRO CODER” http://www.grassvalley.com/products/procoder_3
i use it and works fine.


#3

The question is ‘what is your end delivery format?’

If it’s the internet, then I’d just go with the native frame rate of the file and change the timeline in the NLE to match.

If you’re working for TV, however, you’re going to need to get that frame rate to 29.97

If the After Effects project has no prerenders or 25fps imported footage, then setting an alternative frame rate in the render settings will have no detrimental effect on render times or final quality. There is no interpolation going on. After Effects is just measuring a different point on the timeline.

However, if there are prerenders included in the project, then it becomes more complicated.

One way to do it is to think about the PAL footage as though it were film footage and then transfer it to NTSC as you would a feature film, using a 3:2 pulldown.

To do this, render the project at it’s native PAL. Bring the footage in to a new project and interpret the frame rate of the footage as 23.976. Now make a 29.97fps timeline and drop the footage onto it. Rendering the timeline using fields will now give the footage a 3:2 pulldown. Use upper field first unless you are rendering to a DV codec and interpret accordingly in your NLE.

This will actually slow the timing of the footage down by 4%, but seeing as this is how feature films are shown on European PAL TV (by speeding them up by 4%) it’s a completely standard technique. You won’t notice it in the picture, but you may notice a pitch shift in the sound. If you do, then you may need to time stretch the sound separately, using an app that can do this without altering the pitch.

Of course 3:2 pull downs suffer naturally from frame jitter, since the cadence of the frames is a little strange… every third frame is on screen for a touch longer. But this is nothing that the US audience won’t be used to, since they’ll see this on everything shot on film and broadcast on TV.

If you really want to avoid 3:2 pulldown techniques, then you could try interpolating frames. AE doesn’t do it very well. You might want to look at Re:Vision plug-ins for this, but even so, none of it competes with the power or speed of a Snell and Willcox machine… and indeed if it’s a pro solution that you require, then this is the direction that you should go.

Hope that helps.

-f.


#4

Thanks - hey you really know your video, felt - I took notes/copied that for reference. Very helpful to know about 3:2 pulldowns and how to render for different output formats… that’s exactly what I needed to know. Great tips! right re internet can just do in nle, for dvd production on ntsc tv playback, trying to get to the 29.97 so the process you outlined makes a lot of sense – thanks very much for such a thoughtful, professional answer… much appreciated.


#5

Glad to be of help, Ken.

Another thought though… if you’re converting footage to 29.97 because of mixed footage on an NLE timeline, but your ultimate delivery format is not TV but internet, then using interlaced fields with a 3:2 pulldown won’t be of much help to you, since web players and computer screens scan progressively.

However, you could mimic interlaced footage on TV by doubling the progressive frame rate of your web movie. You can do it like this…

Render your completed edit out of your NLE in fields. Again use upper first unless it’s DV.

Bring that render into After Effects, make sure it is interpreted correctly (i.e fields / upper first).

Make a new timeline at 59.94 frames per second, drop the new material onto it and then render in frames.

By doubling the frame rate you effectively mimic the effect of fields. I have used this many times for showreels that contained footage originally shot on film and footage that was shot on interlaced video, to maintain the feel of the original.

One slight drawback is that you lose some spacial quality. Using the Reduce Interlace Flicker effect in After Effects on the 59.94 timeline before you render might help here. You might also consider importing the rendered edit footage twice, interpreting the first import as interlaced and the second as progressive. You’d then use the latter on the timeline where there was original footage had no pulldown or interlacing and the former where it did. That way you maximize the quality throughout.

It’s a bit of a hassle, but once you get used to the process, it only takes 10 minutes.

-f.


#6

Thanks Ben, helpful indeed. Took my notes. :wink:


#7
miseld said

“A” option for native AE elements is the best, but if you have pre-rendered files in PAL then i suggest you “C” to try “PRO CODER” http://www.grassvalley.com/products/procoder_3
i use it and works fine.

Any comparison with Adobe Media Encoder?


#8
PerfectFX said
miseld said

“A” option for native AE elements is the best, but if you have pre-rendered files in PAL then i suggest you “C” to try “PRO CODER” http://www.grassvalley.com/products/procoder_3
i use it and works fine.

Any comparison with Adobe Media Encoder?

Check link: http://www.grassvalley.com/products/procoder_3


#9
miseld said
PerfectFX said
miseld said

“A” option for native AE elements is the best, but if you have pre-rendered files in PAL then i suggest you “C” to try “PRO CODER” http://www.grassvalley.com/products/procoder_3
i use it and works fine.

Any comparison with Adobe Media Encoder?

Check link: http://www.grassvalley.com/products/procoder_3

Very clever :slight_smile:

One thing is what they promise, the other thing is your personal experience. This is what I wanted to know.