Working with Frame Rates & Slow Motion in Adobe Premiere

Question

I'm a very new beginner to video editing, but I am trying to do the best job I can. I saw this tutorial about "slow-motion basic techniques":

I learned the technique about "changing the frame rate of your video in order to make a good basic slowmotion." This tutorial was made using After Effects and I have some related questions:

1. How can I see the framerate of the clip or sequence in Premiere? In After Effects it is sufficient to click on it and on the top left corner (near to the preview image) the info that you need is displayed (included the framerate).

2. Usually, I use my GoPro in order to make videos. I use 60fps at 720p in order to make "sufficiently good" slow motion, but then I don't know what is the right "Sequence Presets" to choose (I usually use HDV 1080p30, but I don't know if it's the best/right choice) when I create a new sequence, so when I use a GoPro clip in some sequence it appears the message "Clips Mismatch Warning" and I have to choose the "Change sequence settings" option, but then I don't know what are the NEW sequence settings! I want to know what the NEW sequence settings are?

3. Here the most important question: I saw from the above tutorial that the a basic technique for slow motion is to change directly the frame rate of the clip from (for example) 59.94 to 29.97 (as in my case). But then I thought: how can I apply this technique "locally" on the clip? Or better gradually (so starting from 59.94 at a point of the clip and gradually decrease it until it reaches 29.97)? Is that possible in some way? I know that you can right click on the original clip->modify->interprete footage and change the frame rate, but that is for the WHOLE clips, not locally as I need!

4. Then, I had an idea: why they use "change frame rate" and Twixtor SEPERATELY? Why not first change frame rate AND THEN apply the Twxitor effects? I had this idea because I tried to obtain an extreme slow motion using only Twixtor, but the result was really bad! However when I combined the two techniques the results were pretty good. What do you think about it? It is only an illusion (so I don't get something in the process, and there isn't any real improvement), or is it a good solution?

UPDATE: I uploaded this video on YouTube in order to proove that there is a quite difference between applying Twixtor without changing the frame rate and with it. On the left side video you can see the result applying the Twixtor effects, with a speed at 25%. On the right side video you can see the result after changing the fps from 60 to 30 and then applying Twixtor with a speed of 50%. As you can see, the right side video is really better then the left one: it is more "smooth", don't you think?

Answer 1

To answer your Questions in order:

1. You can see the framerate of a clip or sequence by navigating to the metadata panel. It's usually one of the tabs in the upper left on the standard layout. If you don't see it, select Window -> Metadata.

2. Generally, you should set sequences to match you source material. So if your camera records 720p @ 60 fps, stick to that. You can review and change the sequence settings under Sequence -> Sequence settings. Some settings can't be changed later on though.

3. The best way to create a slowmotion effect is to use "time remapping". You will find that under the effect settings that every clip has by default. There you will see that your clip has a standard speed of 100%. You can change the speed of the entire clip by altering that value. If you want the clip to gradually slow down over time, you'll have to use keyframes. You can set a keyframe by clicking on the square symbol in the effects panel next to the time remapping line. In this case, you'll need to create two keyframes, one at the beginning and one at the end of the transition from fast to slow. Let the first keyframe at 100 % speed and set the second to your desired target value, for example 50 % and that's it. I hope this was somewhat understandable. If not, it's futher detailed at the adobe help site: http://helpx.adobe.com/premiere-pro/using/duration-speed.html

4. Can't really help you with that. If you're going for real slow slowmotion, you can always right-click on the clip and activate frame blending, which might result in a smoother video.

I hope i could help :)

Answer 2

1) In addition to the meta-data panel that Gin-San mentions, you can also right click on a clip in the project explorer and hit properties to get details about the file, which I believe includes the frame rate.

2) The new sequence settings are the settings that match your input video. So if the video is a 60fps video, it will end up making the output of the sequence match the resolution and frame rate of the input. In this particular case, you may very well not want to accept the alterations to the sequence settings. You may actually want to use 30fps (or 29.97 if you are recording at 59.94) so that when you drop the frame rate in half, every frame of video still gets its own frame. It is really up to you though, there isn't a right or wrong answer, though I do recommend evenly divisible intervals for best quality slow motion.

3) Gin-San's answer for this is 100% correct. You need to use keyframes and adjust the playback speed via keyframe animation. Keyframes will instruct the video editing software to make sure that the value of the parameter you are keyframing (playback speed in this case) is at the given value on the frame where you set the keyframe. To get it there, it will start making adjustments right after the previous keyframe in order to make a smooth transition between the values of the neighboring key frames. With advanced keyframing, you can also adjust the type of curve used to move between keyframes, making it either linear, logarithmic(changing fast at first but then slowing towards the keyframe) or exponential (starting slow, but changing faster and faster as it approaches the keyframe.)

4) There is no particular reason that changing the frame rate should be needed when using Twixtor. Changing the frame rate doesn't alter the real frame data that is available to Twixtor, so I'm not sure why it should have made any difference. I would guess more likely there was some subtle mistake in the way you used Twixtor that you corrected for in the other test without realizing. Twixtor and changing the framerate to a non-evenly divisible multiple both require the invention of new frames and Twixtor is generally far better at motion estimation, so it should generally be best to use it alone.