Time remapping is an interesting and popular editing technique which you can use to give your videos some polish. Time remapping is simply the process of adjusting, or remapping the speed of a clip, thereby speeding up or slowing down your footage.
This technique is very easy to perform in Adobe Premiere Pro, and in this article we’re going to show you how. If you don’t own Premiere Pro, or you’re looking to edit videos online, you may want to look into these free online video editing tools.
A Primer on Frame Rates
Before diving in, it would be helpful to have an understanding of frame rates. Feel free to skip this section if you already know all about frame rates.
Whenever you watch a movie, it is nearly always played back at 24 frames per second (FPS). This means that for every one second of screen time, 24 frames, or mini photos, were captured. While we won’t get into the how and why 24 FPS has become the gold standard of Cinema (there are a few exceptions such as The Hobbit), it is firmly cemented as the correct way to playback footage.
If you set your camera to record 24 FPS, you’ll be capturing a normal image. Motion won’t be really slow, and it won’t be super-fast like a time-lapse, it’ll be just right. This frame rate closely mimics what our eye sees.
Don’t forget to check out these incredible time-lapse videos if you’re not so sure on what they look like.
If you have a camera that can shoot in high frame rates, otherwise known as slow motion, then you may be shooting at any number of frame rates above 24 FPS. This can be anywhere from 60 to 240 FPS for the majority of cameras, or anywhere up to 250,000+ FPS for the very specialist cameras used by YouTubers like The Slow Mo Guys.
If you shoot your footage at 120 FPS, and play it back at 120 FPS, it won’t look very good. This is because there is not enough motion blur, and we almost expect things to look like the movies at 24 FPS. Shutter speed also factors into this, but our beginner’s guide to aperture and shutter speeds has more information.
Time remapping is simply playing back footage at a different frame rate to what it was shot in. Playing 120 FPS clips back at 24 FPS results in really nice slow-motion. Similarly, shooting at 1 FPS and playing back at 24 FPS will produce a time-lapse, where everything is really sped up.
The Basics: Interpreting Footage
Now that we’ve got the boring bit out the way, let’s take a look at how to achieve time remapping in Adobe Premiere Pro. I’m using Premiere Pro CC 2018 for these examples, but the process is very similar for older versions or even different software.
Once you’ve created a project and imported your shots, performing a basic time-remap can be performed in only a few clicks.
From your project window, right click on the clip you want to remap, and go to Modify > Interpret Footage.
This will open the Modify Clip panel, where you can alter and adjust a large number of settings on a per-clip basis. Whatever you change here will only impact one clip. You can select multiple clips at once to bulk adjust.
Under the Frame Rate heading, select Assume this frame rate, and enter a number in the box to the right.
This number is the frame rate you would like to play back at. You’ll want 24 FPS most of the time, but play around. You can right click and interpret footage as often as you like. What happens if you enter 500 here. What about a lower number like 12?
By interpreting footage, you are time remapping. You can interpret footage to speed it up and slow it down, but this is a bit of a basic method, and may not always work for you. We’ll cover some different methods down below, but there’s a few things to watch out for when interpreting footage this way.
The first is interpreting below your footage. Say you shot some footage at 24 FPS, but you want it to play back in slow motion. You can’t just enter 2 FPS here and expect it to look good. If you interpret footage at a lower frame rate than you shot in, there are not enough frames to fill one second, so Premiere has to compromise. Playing back at 2 FPS means that each frame will be on the screen for 12 frames each, as 12 x 2 = 24 FPS. This won’t look very good, and will appear to stutter. If you want slow motion, you have to shoot in high frame rates.
The final thing to be aware of when interpreting footage is timing. You really should interpret any footage before you begin editing. If you start editing, then interpret and change the speed of a clip you have already used, you’ll need to go and re-edit that particular portion, as it will now be a different section of your shot.
For example, if you make a quick edit, and you use an epic shot of a skateboarder landing a wicked trick at two seconds into the clip, that trick will no longer be at two seconds if you then interpret your footage. If you slow down your footage from 120 FPS to 24 FPS, that’s five times slower (120 / 24), so that trick will now be at 10 seconds.
Confused? Don’t worry, playing around with settings and footage is the easiest way to get a handle on things, and if you always interpret your footage before doing anything else, then you won’t ever have this problem.
While this second time remapping technique is technically easier than the previous one, it’s still essential to have a solid understanding of the basics first.
This method works much the same way, however, here you’ll be able to specify the duration of any clip on the timeline.
Get started by right clicking on a timeline clip and choosing Speed/Duration.
Unlike interpreting footage, this method allows you to speed up or slow down footage by entering a percentage, or by specifying a total duration. Click the number immediately following the words Speed. This will say 100% if you haven’t adjusted the clip before.
If you’d prefer to specify a duration, this can be done by clicking the time after the words Duration. This duration is four number separated by colons. From left to right, these numbers stand for: Hours, Minutes, Seconds, and Frames. This allows you precise control, down to the individual frame, which will be 1/24th of a second, assuming you’re playing back at 24 FPS.
You can leave all the other options as their defaults, however, you can reverse a clip by ticking the Reverse Speed checkbox.
There’s practically no limit to how fast you can go here.
Our third and final time remapping technique is through keyframes. Keyframes are a very powerful tool, which allow you to adjust nearly any parameter over the duration of a clip.
Select a clip in the timeline and go to the Effect Controls panel. If you don’t see this panel, you can enable it by going to Window > Effect Controls.
In this effects control panel, you’ll see some basic controls for motion and opacity. You’ll also see any other controls for effects you may have applied to your clip already. Expand the Time Remapping section by clicking the small arrow to the left of its name.
There are three main parts to time remapping here, and most of these apply to keyframes of any kind. On the furthest left is the name of the parameter you are adjusting. In the case of time remapping, this is simply Speed. There’s also a small blue stopwatch here, but we’ll get to that in a moment.
In the middle is the current value of this parameter. Once you’ve added some keyframes, scrubbing through your timeline will show different values for this.
Finally, the right hand side contains information about the keyframes themselves. Here you can jump to the next or previous keyframe, or add a new one using the small keyframe icon.
On the far right of the effect controls panel is what looks like a mini timeline. You can scrub through footage here or in the main timeline, but this is where keyframes themselves can be viewed or adjusted.
Going back to the blue stopwatch, this button enables or disables keyframe animations for a particular parameter. If you click it now, you’ll get a warning that this action will delete existing keyframes. Think of this like a reset button. If you decide you want to start again, or simply no longer require your keyframes, go ahead and click the stopwatch.
Now, the stopwatch is no longer blue, as the keyframes have been deleted. If you’d like to use keyframes again, click the stopwatch and it will turn blue. You’ll have to start from scratch with your keyframes, however.
Now that you know all about keyframes, we are going to adjust the clip speed directly on the timeline — but don’t worry, you’ll still need your newfound keyframe knowledge.
Find your clip in the timeline, and adjust the clip height by clicking and dragging the dividing line in the track title section. You don’t have to do this, but it makes things a bit easier to see.
Now, right click on the top right of your clip, on the small box which says fx. In the menus that appear, choose Time Remapping and then Speed.
What you’ve just done is enable the time remapping bar. This is a horizontal bar spanning the length of your clip. Click and drag this line up or down to adjust the duration of your clip.
We’re not finished yet, however. What about mixing speeds during the same clip? How about fast forwarding the the boring bits, and then dropping into the action, nice and slow?
This is known as a speed ramp, as you ramp the footage up or down, and is a very popular technique. It’s something we use in our DJI Mavic Air review video, and can really help to make your footage stand out from the crowd.
You’re not just limited to slow motion, however. You can perform what I call a reverse speed ramp, whereby you start at normal speed, and then rapidly speed up, and then back to normal speed.
Once you’ve enabled the time mapping bar, editing a speed ramp is a reasonably straightforward affair. Press P or select the Pen tool from the left hand toolbar.
Using this pen tool, you can tell Premiere to break up the speed/duration horizontal rule. Click to add a point on this line, at the place where you want your speed adjustment to start.
You’ve now divided your speed adjustment into two. You can independently slide the horizontal time bar up or down, in two separate sections. You can continue to divide and adjust as much as you like, but it’s not brilliant right now.
If you’ve sped up or slowed down a section of your clip, you may have noticed something odd. You footage is playing at a certain speed, and then it jumps instantly to the next speed. This is quite sudden. With a few simple tweaks, you can easily convert this into a ramp, so that the speed “ramps” up or down from one to the next.
At the top of your clip, there’s a blue marker wherever you divided the time bar. If you hover over this, you cursor changes to a horizontal double headed arrow. If you click and drag horizontally, you’ll see that your time bar now looks less like a brick wall, and more like a roller coaster. You’ve now told Premiere to gradually adjust the speed between the two, rather than cut directly.
If you look back to your Effect Controls panel, you’ll notice that two keyframes have now been added. You can move these around on your timeline, or in the effects control panel.
One final tweak to really make things pop is to gently curve the in and out point of the ramp. While it’s much better than a sudden speed change, it’s still on the harsh side when the speed adjustment begins.
Select your adjusted time by clicking at the top of the angled line. Notice how a small blue vertical line appears.
Click and drag the small blue handles at the end of this line to adjust the ramp. Notice how it goes from a harsh line to a nice smooth curve.
You should now have some killer speed ramps in your videos! This technique often works best when you combine multiple ramps in the quick succession. Something like a Fast > Slow > Fast edit can look very cool.
Going Pro: Directional Blur
Once you’ve nailed all the essential tricks above, there’s one last effect you can use to really make your edits shine.
If you’re shooting in slow motion, you may find that your footage does not look as realistic as your “normal” shots. This is due to the shutter speed. There’s simply not enough motion blur compared to 24 FPS shots.
Fortunately, it’s very easy to add some motion blue back into your shots, and by using keyframes you can only have it for the fast moving moments.
Start in the Effects panel, which you can bring up by going to Window > Effects if it’s not visible already.
Using the search bar at the top, type in Directional Blur. Found under Video Effects > Blur & Sharpen. Drag this directional blur onto your clip.
Going back to your effects control panel, you’ll now see a new entry for directional blur. As you probably don’t want a blur on your slower shots, you’ll need to use keyframes to only apply blur to the faster moments.
Start by positioning your playhead where you want the blur to start. This will probably be the same place your time remapping keyframe starts. Click the stopwatch next to Blur Length. This will enable keyframing for the directional blur length attribute, and create a new keyframe. Press right on your keyboard to move forward one frame, and then press the new keyframe button. Remember from our keyframes section, this is to the right of the effect controls property section.
The reason for two keyframes is simple. If you just have one, Premere thinks that you always want the blur, and will start adjusting it from the next keyframe. Adding a keyframe one frame later, and adjusting that gets around this.
Anyway, while you’re here, change the Direction attribute to 90. There’s no need for a keyframe on this parameter. This direction specifies which way you want the blur to work. In this case, 90 is horizontal. You may want to keep this at 0 for vertical movement.
Finally, go ahead and do the same procedure in reverse. Add a keyframe where you want your blur to stop. Skip right one frame by pressing the right arrow key, and then set the blur value to zero.
How Do You Edit Your Slow Motion?
Maybe you’re more like us, and can’t stop watching unbelievable slow-mo videos. Either way, experiment to your heart’s content and, above all, have fun!