[SOLVED] My 60fps video (Shutter 1/125) looks choppy at 24fps when down 40%

elzorrocr Posts: 3

I think my title is pretty self-explanatory, but i have had this issue literally for years. I am not able to figure out how to get smooth slowmo from 60 fps to 24 fps when slowing at 40%, always at a low ISO. My video always looks either choppy or with a weird echo. Is this a problem anybody has with HF Express? I have tried to change my shutter speed but this continues to be a problem. 


  • triforcefx
    triforcefx United StatesPosts: 1,476 Moderator

    @elzorrocr HitFilm has never handled slow-mo very well... but we've been assured that vast improvements are coming "soon". Luckily for your situation, there is a simple solution... (please don't beat yourself up too much about not asking this sooner)

    In the Media panel, there is a gear/cog icon next to every piece of media. Click it and you will get a Media Properties popup. Under Video > Frame Rate, uncheck the From File checkbox. Change the Frame Rate to match your project's frame rate (24 in your case). Hit OK and now your 60 fps file will play in smooth slow mo. You can now use the Speed tools to adjust it faster or slower.

  • NormanPCN
    NormanPCN Posts: 4,134 Enthusiast
    edited February 2020

    " I am not able to figure out how to get smooth slowmo from 60 fps to 24 fps when slowing at 40%,"

    There are three ways to slow down media in Hitfilm. Which one did you use?

    1. Use the speed effect
    2. Use the rate speed tool.
    3. Have a second copy of the media imported into the media panel and change the frame rate from 60fps to 24fps.

    I think I can guess that you used the speed effect given you mentioned a "weird echo". The speed effect in Hitfilm performs frame blending when resampling the timeline clip. Nothing else does frame blending. Not rate speed or internal Timeline conforming.  So there is no way to have Speed be visually compatible with the other options.

    You should use method three with media recorded and marked at a high frame rate relative to your timeline frame rate. The other two suck at various levels.

    To understand why you need to know that Hitfilm conforms your video from its native frame rate to the timeline frame rate. Only then does the either the speed effect or rate speed tool operate on the result. The mechanism of conforming will throw away most frames of 60fps media when placed on a 24fps timeline.

    By using method three, you are telling Hitfilm to play the media at a different frame rate than marked in the media. In your example you mentioned 60fps media and a desired 24fps rate. You probably have a 24fps timeline. 

    The frame rates offered in the media panel are limited. You are always better off with a slightly lower speed than desired for your slowmo in the media panel and then speed up the timeline clip using option 1 or 2. The big thing is to avoid the timeline conforming process throwing away most of your slomo media frames before you ever try to do slowmo. The whole point of using method three.

    An interesting side note. Method 3, is kinda simulating the way "pro" cameras record slomo. They keep the media frame rate at 24fps for example, but they record at 60/90/120/whatever fps. It is already naturally slowmo. Consumer cameras typically mark the media with the higher frame rate they are recording at.

  • triforcefx and @NormanPCN, I really appreciate you help. Both responses appear to be similar and I may have tried a slight variation of it with not too successful results, at least with the one provided by @triforcefx. @NormanPCN, is option 3 what @triforcefx is referring to? If not, would you mind explaining further?

    Once again, thanks very much. Very kind of you. 

  • NormanPCN
    NormanPCN Posts: 4,134 Enthusiast

    @elzorrocr "NormanPCN, is option 3 what triforcefx is referring to?"

    Yes. Change the frame rate in the media panel for high(er) frame rate source media (e.g. 60) that you want slower frame rate playback (e.g. 24). AKA slomo.

    If all you want is slowmo from that media then just modify the one import. You you want normal speed playback and slomo, then you need two items in the media panel for a specific media file. One for normal speed and one for slowmo.

  • @NormanPCN it looks like it just worked beautifully, I noticed that I was using the speed effect additional to changing frame rate and that is why my footage got all choppy. Thanks so much the thorough explanation. I really appreciate it.

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