How to Create Super Slow Motion Effect in Adobe Premiere Pro CC (Optical Flow vs Timewarp)

INTRODUCTION 

In my previous video on creating super slow motion in adobe premiere pro i showed you the new time warp feature in the effects panel however it seems like a lot of people don't have this effect yet it may be due to the the version or the operating system i can't quite seem to figure out why but as a lot of people mention in the comments there's also another way to do super slow motion if you don't have this effect and i'm going to discuss the pros and cons of each so that way is in the speed duration optical flow

30 FRAMES PER SECOND 

 so let's just take this clip for those who are wondering this clip is shot in 30 frames per second and you can see that when you highlight the info tab and you can play it it's a woman walking through the street so there's some camera motion in the frame but there's also motion in the subject so that's what it looks like normal motion and if i right click and go to speed duration if i were to lower this let's say to 50 percent

INTERPOLATION METHOD

 it's going to look choppy because now we have a 30 frames per second stretched out in half so about 15 frames however the sequence settings are still 30 frames and you're going to notice it looks a little choppy if i do that even more right click speed duration change it to something like 20 you'll notice it looks even more choppy now we can literally see those frames being stretched out frame by frame because they have to fill in this new space however if while you're doing that if you change the interpolation method

FRAME SAMPLING

 so time interpolation if you change it from frame sampling to optical flow this will do a similar result as what i showed in the previous tutorial and it will create a flow of those frames by creating new frames in between now you'll notice that this bar immediately turns red it is a little bit of a heavier effect so if you want a easy way to preview that you can press i on your keyboard go to a certain point and press o and then press return key and it'll render a preview for you so once this is done i'll show you what this looks like

LIGHTING

 so here you can see we have some super slow motion and we've created those new frames so it's not as choppy this is going to depend on the context of your clip whether the lighting is changing really fast or the scene is changing really fast in this case the only thing that provides a problem for premiere is uh the very fine sort of black and white stripes on this great on the street you can see that that causes a little bit of an issue on one or two frames

DEPENDING ON YOUR CLIP

 which you're gonna have your own issues and glitches depending on your clip but as far as for a lot of portions of this clip it does add a really nice slow motion to the walking here so that's us taking that clip down to 20 if i were to do the same thing with time warp it still works with time warp so if i take the speed and turn it down to 20 change the method to pixel motion you can see here it's essentially the same actually it does do a little bit of better job in this clip with the grate

SPEED

 you'll notice the speed is the same we've taken each clip to about 20 percent of its original speed uh just by happenstance it happens to work better in in the case of the grate there but you know if you don't have that feature or you know i can easily imagine a time where the optical flow might work better on a different clip so as far as pros and cons you'll notice i mean there's one pro sometimes this might work better 

FLEXIBILITY

you have more flexibility inside of the time warp effect as far as fine tuning so in the effect controls panel you have all of these options for fine tuning as well as options for motion blur and other mats and crops so that's one reason you might want to experiment with the flexibility of time warp as far as just optical flow however another a con of this is that even if i stretch the clip down to 20 percent you can see when i do that for the optical flow or the the clip that we stretched using speed and duration method it extends the clip 

INFORMATION

so we don't lose any of information from beginning to end of the clip we get all of the clip this is like stretching out the clip but it still is going to keep its same duration so whatever we're able to make 20 it cuts off right there and if you wanted it to come back you'd have to drag another instance of the clip out which you could do you know match up the cut point and do whatever you want another thing to remember is you can you can speed ramp with time warp so i can add keyframes onto the speed 

ADD A FEW KEY FRAMES

so if i wanted it to begin at a hundred and then quickly go in to 20 all i have to do is add a few key frames and it'll go from 100 to 20 and i can i can adjust the interpolations of those keyframes right click make them ease in or out or even drop down that menu and adjust these ramps between these keyframes but this will essentially quickly go down from 100 speed to 20 speed this will dramatically increase the rendering time but you can see 100 boom it ramps down to 20 i can add keyframes to make it go back up or whatever 

MOTION ALTERNATIVELY 

 I want if you wanted to do that with the optical flow method you could also right click on this clip add a show clip keyframes timer mapping and speed if i make this v1 track a little bit bigger by dragging on that line i can see that line and if i hold the command key i can add points on that line so i can start out at a faster speed it's kind of counterintuitive because it's at a hundred percent of 20 percent but i can increase the speed and then add another point maybe increase it and i can drag and split these two markers and you get a similar idea of ramping into or out of motion alternatively 

CREATE NEW FRAMES

you could also just take the clip and let's say if i wanted it to begin being slow motion right here i could cut that part maybe just cut out the section i want to be slow motion and i could right click and use the speed duration on that part so take this to 20 with optical flow i'm just using the number 20 you can go for 10 or 30 percent different percentages are gonna uh work better or worse you know the lower you go the more you're going to make it optical flow have to try to work and create new frames

LITTLE PORTION

 so you might find it to be more difficult to go super slow but you can see the new duration of the clip will now be 17 seconds this little portion right here it'll have to be 17 seconds long if we stretch it out basically divide it by five and then i can just bring this other end back in another way to do that is check the ripple edit button that's what that's there for um let's say i make this even slower it'll just push everything over instead of getting cut off so do keep that in mind if you want these to be seamless 

HIGHER FRAME RATE 

so yes you can also use optical flow if you don't have time warp one thing to to note in whether your photo or video editing is there's always multiple ways to reach similar effects it's sort of like mathematics where two plus two equals four three plus one equals 4 6 minus 2 equals 4 you can get the same result in different routes um so but you have all these tools for you in your toolbox this doesn't replace just shooting in a higher frame rate i'd say it can work great for a majority of clips but you can see there's times 

OPTICAL FLOW 

where the clip doesn't work well and you do you can kind of tell the difference between a clip that has frames that have been created using optical flow or time warp there's just something a little different about it a little uncanny whereas if you shot in ultra high frames per second you're just not going to be able to replicate it exactly so i'm not going to say that this is going to replace a high frames per second shot exactly but you can definitely use it for clips that are 24 frames or 30 frames per second if you don't have a camera that can shoot very high or if you're just in a pinch or that's that's all you can work with

CONCLUSION 

 so it's definitely a great added tool for getting smooth slow motion my name is justin odisho if you enjoyed this video you could subscribe to my channel here on youtube and check out hundreds of more videos like this on my channel thank you so much for watching and i'll see you in the next one

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