I'm new in editing slow-motion footage, I recorded my videos in 120 fps and now Hitfilm is having a hard time exporting it, It's giving errors. What can I do to retain the slow-motioness of my video? Thank you!
I really cannot see why you would want to export 120fps.
You talk about Slow motion. If your output is 120fps then for slow motion your camera must have recorded at well above 120fps.
I can speculate based on some information in your post. Action cameras can record at high frame rates. 120fps is one of those. (For GoPro and to be precise 119.88) Unlike most cameras recording slow motion the action cams mark the playback speed as "normal" and the high record rate. To get slow motion you have to playback at a frame rate slow than the recorded. In Hitfilm you do this via the Media panel properties.
Most pro(ish) like cameras mark the file at a normal playback rate, say 24 or 30fps, but record at a higher frame rate. e.g. 120. Therefore slow motion without any adjustments.
Again speculation, so really you want a normal/standard playback rate in your project. Like 24 to 30 fps. The speed of your normal speed recording if you have such media. If all your media is recorded at 120fps and you want some of it slow motion and the rest at normal. Then choose a standard/common/typical playback rate for the timeline, e.g. 29.97. Import the media twice and on one of them change the playback speed to something less than 120fps for slow motion. e.g. For 1/2 speed 60/59.94, for 1/4 speed 30/29.97. Doing it this way will have Hitfilm use all the recorded frames for slow motion. The speed effect for sure and probably rate control will just duplicate conformed frames and the slow motion will not be as smooth.
Okay, I get your point. The reason why I recorded my videos at 120 fps so that in post, I can easily get a smooth slow motion shot. I don't really have a high-speed camera so I ended up with shooting at 120 then slowing the footage down at Hitfilm. If I don't shoot it at 120 fps, the slow motion effect will look trashy (For me)
Anyways, thank you for your response. Appreciate it.
You're SUPPOSED to record at 120fps, and play it back at 24fps. When I record 120 fps, I have to transcode it to use it in HitFilm, so I export it as a 24fps clip, which plays in slomo... then for speed ramping, you'd take that clip and play it back at 5x speed to get "normal" speed, and you can then ramp it down to 1x to go back to slomo playback.
As others have said, recording vs playback settings can already make your footage slowmotion, without apply the effect.
Something like this is happening
So, by reducing the playback to 30fps you get smooth slowmotion because you are using all of your 120 frames, but viewing them 3 times slower.
If you try to stretch a 60 or 30fps, and playback 3 times slower, you get no extra frames, so the effect would look weird, and that's why. The software has to "create" the frames inbetween, and that is not always accurate.