Slow motion

I'm having a go at shooting some slow-mo. I'm going for the in camera slow motion instead of just slowing the speed/duration.

So, I walked the hallway filming at 60fps, with a shutter speed of 125.

How can I actually VIEW this in slow motion?

This all started with figuring out image stabilization, by the way (see previous thread I made).  A recommendation was to try and film in slow motion to take some of that shaky edge off.  Anyway, when I play the brief clip back it's not "slow motion".  

Cruising YouTube, as usual, and the Adobe people use the term "interpret"...which I understand to mean pretty much playing it back at the normal speed (24fps).

How do I do this in HitFilm?



  • CleverTagline
    CleverTagline Posts: 3,341 Ambassador

    First off, you'll likely need to transcode your footage. Many cameras that shoot high speed (or even normal speed) encode with a variable frame rate.  The HitFilm crew has done a lot to make VFR more reliable to work with, but it's still best to transcode for a lots of other reasons, and from my experience high speed footage definitely needs to be transcoded so that HitFilm correctly reads its higher rate.

    Once that's done and you bring it into HitFilm, it should read as a 60fps clip.  What you then need to do is edit the properties for the clip inside of HitFilm, and manually change the frame rate to 24fps.  Now when you drop that onto the Editor timeline, it will appear in slow motion.

  • Is nothing in this place simple?

    Ok, so transcoding.  How is a good place to start, I guess. 

  • CleverTagline
    CleverTagline Posts: 3,341 Ambassador

    Sorry.  Should've posted this link with my last post:

    Yes, it's an extra step, but it's well worth it in the long run.

  • Triem23
    Triem23 Posts: 20,275 Power User

    Is nothing in this place simple? 

    Not much. Editing and VFX is pretty complex. 

    That said, transcoding for VFR is something that has to be done in pretty much any NLE. Editors attempting to correctly parse VFR footage has only happened in the past year or two--before that, transcoding was required for VFR, period, or your final output would absolutely have audio drift. 

    The NLEs that do try to interpret VFR footage do so with varying rates of success. This isn't the fault of the NLEs at all. To cut video at 30 frames per second, the editor needs to SEE 30 frames per second. If a camera is shooting a file that varying between 28 and 32 its a problem. In one extreme case a "29.97" fps clip shot on my phone had a VFR framerate that moved between 20 and 31. Any NLE I drop that clip in gets auto-interpreted as 23.97, 24 or 25 depending on the software.

    As far as auto-interpreting speed of an imported clip--the convention (and this, again, goes for pretty much every NLE) is that imported footage, by default, should be "interpreted" to play at "normal" speed at the current timeline settings. This is the correct and desirable behavior, where attempting to conform for auto fast/slow motion playback would not be.

    Why? Well, I did some work on a documentary recently. The final documentary will be output at 29.97 fps. Source footage is from 23.97, 25, 29.97, 30 (yes, there's a real difference) and 60 fps sources. If default behavior in the NLE were to do "per frame" playback (one frame of source video =one frame on timeline) I would have to be correcting the playback rate of almost 80% of the used clips--none of which are supposed to be in fast or slow motion. 

    Changing the playback rate of a clip isn't a huge pain, and, ultimately allows the Editor to take control of the creative decisions. 

    Now I'm going to have a flashback to the days of yore before any NLE had speed ramping to a lovely evening I spent cutting a speed-up-fast-motion-slow-down ramp by manually slicing out frames... 

  • So, this is where two recent discussions I have started kind of merge. 

    I just stabilized a couple of shots that I took around the station. I did this in DaVinci Resolve. They were shot 60fps. 

    Lets say that the stabilize was a complete success. Is it too late to “transcode” the clips so I can pull them into HitFilm, interpret, and achieve that slow motion effect?  Or should I have transcoded them before even messing with them? 

  • Triem23
    Triem23 Posts: 20,275 Power User

    Let's quickly discuss transcode vs render. In both cases one is writing a file to a drive. A render is typically writing a file after editing in some way while a transcode is writing a copy of file A to file B. 

    If you've stabilized in Resolve you'll just render out to an appropriate format to start with. This should be easy, as, more the most part Resolve won't write the type of highly compressed (or VFR) file cameras often do. Resolve should have controls to render to mp4 using the so-called "Norman AVC" settings (incidentally, NormanPCN did a good month of testing to come up with those settings, which give a good blend of file quality and responsiveness). Or, rendering out in Cineform (Medium quality should be fine. Maybe High. Filmscan is overkill) will generate even high-quality more responsive files.

    In short, you should be fine just taking the Resolve render to Hitfilm. 

    In general, transcoding for VFR issues should be done before editing. Transcoding just for increasing editing responsiveness is technically optional. Sometimes I don't bother if I know it's a super quick edit. 

  • You're like some kind of professor...wizard dude. And you're pretty much always on call too.  On point! 

    So how do I go about transcoding a clip?  And once I've done so, I should be able to drag it into HitFilm and edit the properties (as explained by jsbarrett). Ta-da! I have a clip that plays in slow motion. 


  • CleverTagline
    CleverTagline Posts: 3,341 Ambassador

    "So how do I go about transcoding a clip?"

    See the video I posted above.  It's a creation of the professor-wizard dude himself.  :) The first part talks about the whys of transcoding, and then he gets into the how.  Don't skip over the first portion, though. It's useful to know.

  • Well I tried to download handbrake to my Mac. When I went to run the install a box popped up saying it “can’t be opened because it is from an unidentified developer”.  And that my security preferences allow installation of only apps from the App Store and identified developers. 

    I would rather keep it this way, as I am not computer savvy enough to deal with this thing if stuff gets all wonky and my computer ends up getting compromised or diseased. 

    If I bypass this (which apparently there is a way to temporarily skirt the issue and install it), will I be at risk? 

    Not sure if other Mac users are reading this.

  • GrayMotion
    GrayMotion Posts: 1,632 Enthusiast
    edited February 2018

    Handbrake is a perfectly trusted app. As long as you download the DMG from the source developer you are safe to override your security preference one time for that app.

  • Is it from the source developer? I don’t know. 

    A google search and I clicked on the download for Mac. 

  • JMcAllister
    JMcAllister Posts: 589 Enthusiast

    Here's a link to the download page of the handbrake website. The page also has some notes about downloading on a Mac and about verifying whether the download is legit

  • BobDiMarzio
    BobDiMarzio Posts: 624 Just Starting Out

    @Jsbarrett @Triem23  @HitFilmer128619

    Either I missed something or did you guys  misunderstand   what Hitfilmer  said.     As I understand it, he shot footage @ 60fps with a shutter speed of 125, correctly following the 180 shutter rule.  

    When he brought the footage into the HitFilm  it played at "normal  "speed" because Hitfilm "Assumed" that's what he wanted.

    All he had to do  was Right click his clip in the media panel and select properties.  While in Properties he should have unclicked the little box to the right of Frame rate.  and Change the Frame rate to his standard rate.  Since he Shot at  60 (most likely 59.94) I would recommend  29.97.  and Volia Smooth slow motion.

    If @Hitfilmer128619 would like to  stabilize in resolve first and then edit in Hitfilm, I recommend the following steps.

    1) Bring Clip into resolve media.   when asked "The Clip(s) have a different frame rate than the current project settings.

    Would you like to change your timeline frame rate and video format to match?

    SAY--> Change

    2) in edit panel drag to the timeline,  switch to the color page and Stabilize.

    3) On the Deliver Page


    Format:  Quick Time

    Codec:  GoPro Cineform RGB 16bit    (This also effectively transcodes the footage to an easy to edit format) 

    Open Hitfilm

    Bring in Footage into the media Panel.

    Right click on the  clip in the media panel and select properties.  While in Properties ,  unclick the little box to the right of Frame rate.  and Change the Frame rate   I recommend 29.97 For the smoothest.

    Edit your slow mo video.

  • ^^^That is how easy I thought it would be. But then we got into a conversation about codecs, and transcodes, and the matrix and whatnot. Talking about downloading programs to manipulate the clip itself before uploading it to the timeline. 

    Watching YouTube videos on how to shoot slow motion, or any videos with slow motion action shots, I didn't see anything about installing handbrake to "transcode" or whatever.  As you guys can probably tell, I'm not a computer guy.  I don't care about coding and all the other computing acronyms.  I just want to shoot some amateur film and have fun with it. 

    I understand that there are some computer nerdy things that I will just have to suck up and get used to, but it seems like whenever I have a question about how to do something that seems relatively simple, the reply usually has something to do with installing other software and using additional steps. 

  • BobDiMarzio
    BobDiMarzio Posts: 624 Just Starting Out


    Did you try what I recommended   with your footage, and did it work for you?



  • Yes!

    And it sure did. Thanks! 

    Real quick...would I be able to get it slower shooting 60fps, but with a higher frame rate than 120? Or do I actually need a higher frame rate to shoot with the higher shutter speed? 60fps is as high as my camera goes. 

    And thanks again. Your advice worked. 

  • BobDiMarzio
    BobDiMarzio Posts: 624 Just Starting Out

    I think you meant to ask "Would I get slower output  if I continued to use 60 Frames per Second but with a shutter speed greater than 120.   No.  Slow Motion  is working because with shooting at 60 frames per second and playing back  at 30 frames per second, it now must process twice the amount of frames for the same second.  It's the same as if you are able to deal 30 playing cards in a second and I now tell you to deal 60 cards without speeding up, it will now take you 2 seconds or twice the time.

    However, you are not limited to just frame rate  to slow down you clips.

    In the a composite shot,  Go to the effects panel and look in the Temporal folder and select speed.  It is adjust by percentage.  I'ts normally set to 1.  If you want half speed change it to .5 etc.   experiment larges changes result in choppy footage.  Also Temporal changes are taxing on your system so expect some delays. 


    hope this helps.



  • Cool man.

    Does that effect work better than just using the speed/duration? You know what I’m talking about...that clean, smooth, slow-mo.

  • NormanPCN
    NormanPCN Posts: 4,367 Expert

    "So, I walked the hallway filming at 60fps, with a shutter speed of 125.

    How can I actually VIEW this in slow motion?"

    Bring the footage into Hitfilm. Change the playback rate of the footage (right click media properties). For example 30 fps would be slow motion at half speed of 60fps media. Audio will still be at normal speed. To be pedantic your 60 fps is probably 59.94 and 30 fps would be 29.97.

    By changing the playback speed in media properties, ALL recorded frames are used by Hitfilm, nothing is interpolated/resampled. Something like this could be where someone uses the term "interpret" in the tutorials you saw.

    If you use the rate stretch tool in Hitfilm or the Speed effect in Hitfilm then the project frame rate comes into play. This is because Hitfilm first conforms your source media frame rate to the timeline frame rate and THEN does a resampling of the media with Speed or rate stretch.

    So a 29.97 timeline rate with 59.94 media slowed to 50% by either tool, will first lose half the frames that were recorded due to the timeline rate conformance and then re-create additional frames with the resampling. Slow motion is never as smooth doing it this way. It is no better than if you just slowed down media recorded at 29.97 in the first place.

    Hitfilm media properties only offers certain frame rates that you can set. So the slow motion factors you can get are limited via media properties. If you want a rate somewhere in between then I am not sure what workflow would be best. It could be best to setup a slower factor than desired and then speed up with the rate stretch tool or speed effect. Or just choose the closest rate and use rate stretch. Or you may need to create a comp at the slow motion rate used in media properties and then speed up that comp. Speeding up normally mostly only throws away frames which is better than creating new ones from the existing frames. We want to avoid Hitfilm doing a conformance resample so we do not lose any frames in the recorded media.

    It would be a lot easier if something the rate stretch tool had visibility to the source media frame rate so we could just drop high speed media on whatever timeline and then adjust the speed and it all works out fine but Hitfilm does not operate that way. Maybe some day Hitfilm can join the crowd.

  • CleverTagline
    CleverTagline Posts: 3,341 Ambassador

    @HitFilmer128619 I'm glad that it worked for you without going through the transcode process, but transcoding is still recommended.  It creates a media file that HitFilm can more easily scrub through when editing (see the video), and in some cases, it actually fixes incorrectly-read frame rates.  I tried to mess with a video shot at 120fps not long ago, but HitFilm couldn't recognize that frame rate without transcoding the file first.

  • I did run into a little problem. I just inserted a slow motion clip into a video. But the clip itself decreased in size. 

    Any ideas? 

  • Juda1
    Juda1 Posts: 298 Just Starting Out*

    Size of comp? Size of clip? If the second is smaller you need to scale it.

  • It’s on “scale to fit” but it’s still sitting in the middle of the frame with space around the edges. 

  • Or do I need to go to transform >scale?

    if so, how do I know what to change the scale to? It’s at 100%.

    also, why did this happen?

  • Triem23
    Triem23 Posts: 20,275 Power User

    Why? Hitfilm defaults to importing clips/videos/photos and putting them on the timeline actual size. 

    Without knowing which camera you used to shoot, this is a guess, but it's not uncommon for cameras to shoot lower resolution at higher frame rates. Using my Dad's Samsung Gs5 as an example, that shoots 30fps in 1080p, but 120fps at 720p. It's slow motion clips are lower resolution, and, if dropped onto a 1080p timeline will appear as a smaller frame with black around all four edges--because it IS smaller.

    On the Editor Timeline right-clicking and selecting scale to frame should take care of it. Or, manual scale in Layer/Clip properties. 

    Proper scale resolution can be found by dividing the project resolution (either dimension) by clip resolution. In the Gs5 example if my project is 1920x1080 and I bring in a 1280x720 slo-mo clip, well 1920/1280 or 1080/720 both equal 1.5. This is 150%.

    In general, for a compositor, bringing in media at 100% is desired behavior. One is often bringing in larger media for backgrounds. In general an editor scales clips to timeline dimensions automatically. Hitfilm started more on the compositing/VFX end so it leaves imported media at 100% by default. 

  • Ok, thanks. I ended up ditching the clip because it kind of sucked anyway, but I have a couple more that I plan on using. 

    I did some slow motion tests the other day and they turned out fine...same camera. 

  • Instead of making ANOTHER thread, I’ll just post here.

    How can I speed up part of a clip. There are a few shots where I went a little long and over-dramatic with the pan from subject to subject. 

    I was thinking I could just shave a few seconds off in the middle by accelerating the footage. But I’m not sure how. I sliced a chunk out and set the speed a little faster, but it jacked up the entire shot. 

  • JMcAllister
    JMcAllister Posts: 589 Enthusiast

    use the rate stretch tool

  • I don’t want to stretch or change the speed of the entire clip, just a big chunk of the middle of it. Do I still slice out the middle and rate stretch that part? 

This discussion has been closed.