ELi5 – Confused about slow motion video


Mainly iPhone related- what is the slow motion video setting good for when I can take a normal video and edit it slower in iMovie? Mainly which would result in higher quality, a 1 minute video slowed down in iMovie that is therefore longer or a 1 minute slow motion video that is automatically slower when played back?

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3 Answers

Anonymous 0 Comments

Let’s say you normally play back video at 30 frames per second. That means that each frame covers what happened in 1/30th of a second.

When you slow that down to have speed, each of those praying still represents 1/30th of a second 4th of action, but you are now seeing them twice as slow so everything looks jerky.

When you film for slow motion specifically though, you feel more frames per second. So you film a 60 frames per second and then play it back and have speed, and then you are still getting 30 frames in every second of video. So that way things continue to look just as smooth as they would normally

Anonymous 0 Comments

A video is nothing but a series of photos taken very very quickly, played back to you at the same rate (ignore audio for this, of course)

If you slow down your video on iMovie, you won’t magically take more photos, instead, you’ll either play these photos back at a slower rate, or, on certain softwares (not sure if iMovie will attempt this), they may try to “guess” the intermediate pictures.

Shooting on slo-mo means you take more “photos” while recording, so the quality would be better, since you’re not extrapolating from limited info, you’re actually collecting more info right at the source.

Anonymous 0 Comments

You only have so many frames in a video. If you capture 30fps video and try to slow it down to 1/100th regular speed, youll be left with a “video” running at 0.3 FPS, so basically more of a slide show than a video.

A slow motion video captures more FPS before it’s slowed down, e.g. if you film at 3000 FPS you can then slow the video down to 1/100th speed and be left with a 30 FPS Video.

Additionally the higher frame rate means a much higher temporal resolution, e.g. you can see fast stuff happening. If you film at 30 FPS and something only takes 1/60th of a second to happen, you can’t film it happening. On one frame it won’t have happened yet, and on the next it’ll already be over. If you film at 3000 FPS you can actually capture frames in between the thing starting and ending