Footage slows down

[elena.petrov]

Dear experts,

Please help an absolute noob.

The footage that I base my work on in After Effects should be about 10 min long. I recorded only 2 min, just for a trial. It's MPEG-4, 614.5 MB.

It slows down at different times, which shows that it is not a problem with the footage but with how AE reading it (I suppose), which makes it difficult to add an animation to it. 

But my main concern is what would happen with 10 min footage if there is such a problem with 2 min one.
I mean, will I even able to do anything with it?

Could someone, please help me with this?
What should I do to fix the problem?
How big should be a footage file, in terms of MB?

With the greatest appreciation to those who can help,
Lena

[P.M.B]

Are you saying you've imported a 600mb mp4 or that's what you're rendering out?  Please exaplain exactly what you are doing if you're working with the .mp4 inside AE tell us what you are doing to it and tell us your system specs.   Also I'll maybe be the first to tell you AE is not video editing software, it's for short shots.  If you are editing a 10 minute video you should be using proper video editing software like premier or... 

[elena.petrov]

Thank you very much for replying.

What I need to do is to video-record myself talking for about 10 min, which, I thought, I would import into AE and add some layers with captions and animations on top of it. Do you think that AE is not appropriate for this kind of job? 

I'm not sure what specs you would like to see, here what I think they are: macOS Mojave 10.14.6 (18G87): 

(Retina 5K, 27-inch, Late 2015)

3.3 GHz Intel Core i5

8 GB 1867 MHz DDR3

AMD Radeon R9 M395 2 GB

Thank you very much for your help

[dj.summitt]

Hi! For what you describe you can use AE or Premiere. Either work. The answer isn't really straight forward. So the issue isn't file size or video length. Running AE on an i5 isn't ideal. 8gb RAM is under minimum spec. And 2gb gpu ram is minimum spec. So your machine is underpowered. That said, trying to use h264 in After Effects is not a good idea. I would try converting it to a better working codec like ProRes. Due to the heavy compression (and other things) h264 playback in AE isnt great. Even on an underpowereed machine you can get it done. It will just be annoying and difficult. 

[elena.petrov]

Thank you very very much for this