Hello;

I have seen a few posts about frame rates and iMovie. As I understand the frame rate for slow motion is best be be 2x. I mean if I am going to have a movie of 30fps as the product to post on youtube or whatever, I shoudl film at 60fps.

Let me tell you what i am trying to do and where I am getting hung up.

I have filmed a few panorampic shots, and at points I want to speed up the rotation and other times even slow it down. So, if I understand corrctly, the "first" clip I drop into the timeline of iMovie sets the "frame rate" and it is non-modifiable. So, I am filming at 60 and when I tell iMovie to cut the speed by 50% it is lowering that to 30fps and then when I export the file it goes back to 60fps and I get choppy results. That make sense?

So, it seems to me that I need to set the "time line" in iMovie to 30fps and insert clips there that are 60fps and slow them. Right? To set iMovie to 30fps I need to insert a 30fps clip and then later remove it?

Question then is what happens to clips I insert that are 60fps and not slowed down?

I cant tell you much about iMovie, I can highly recommend Lumafusion for IOS, its about £20 but worth every single penny.
Yeah the basics are your output fps should be the same or multiples of your captured input. e.g. Capture at 60fps, output at 30,60,90,120 fps or capture at 24fps, output at 24, 48, 96 etc. This will help prevent stutter in your videos. To get nice slow motion shots in your video capture at 60fps or above and slow the video to a multiple of your output framerate. For example. Capture at 60fps, slow down by 2x and output at 30fps, capture at 120fps and slow down by 4x and output at 30fps or slow by 2x and output at 60fps. Remember that at higher framerates you might get aliasing in your video (where some straight edges get a stair effect or brickwork/roofs can have moire going on) due to the way the camera has to pixel bin information to retain the high framerate.

In my workflow I capture at 1080p@60fps and slow down by 2x to get nice slow motion action footage but if im going for the cinematic feel to my content I capture at 1080p@96fps and slow down by 4x and output at 24fps. Remembering to get the shutter at about 192 to get that nice motion blur.