Best way to change frame rate?

[Ron Hunter]

I recorded some slider footage today at 1280x720 60p with the intention of creating a movie with the footage playing in "slow motion" at 24p. However, once I loaded the clips into PreEl12 I realized I wasn't sure the best way to do that. Frankly, I thought a 60p clip would automatically expand when placed on a 24p timeline, but it didn't happen.

I tried two approaches today:
- created a DSLR 720 24p project, imported my 720 60p clips, I saw no orange line at top of timeline to indicate rendering needed and the overall length is 8min 30sec. When I output the timeline as M2T 1920 x 1080 24p, the length was still 8min 30sec and the clips were playing at normal speed.
- created a DSLR 720 60p project and import the 60p clips, again I saw no orange line on timeline, overall length again was 8min 30sec.

What is the best way to have these 60p clips play back at 24p? Do I apply "time remapping" to each clip and try to achieve a reduction ratio that approximates 24p? Or something else?

[Steve Grisetti]

The frame rate has nothing to do with the speed, Ron. If you shoot 60 frames per second and load it into a project set up for 24 frames per second, the program will just blend the frames to make a 24 fps video out of it.

To slow down or speed up your video, the best tool is the Time Remapping tool.

[Ron Hunter]

Thanks Steve!

[Kent Frost]

Not sure how to do it in PRE, but if there's a way to change the playback speed of your 60p clip to 40% on a 24p timeline, that should nail it.

[Ron Hunter]

Thanks Kent, that helps a lot! I'll try that and post up what I come up with.

During a recent podcast with Dave Dugdale and "Knoptop", Dave said he likes to shoot in 60p and then play it back in 24p for a smooth slow motion effect. I've seen that effect in his slider videos and I want to try it out, thus the motivation for today's inquiry.

[Bob]

"Speed" is not a function of the project frame rate. Each clip has a frame rate associated with it and it's that frame rate that determines the speed. If you place a clip at one frame rate into a project with a different frame rate, Premiere Elements will attempt to conform the clip to the project frame rate in a way that will preserve the apparent speed of the clip. Depending on the rates, you may get dropped frames, added frames, or blended frames. If you want to change the apparent speed of the clip, you can either use the time remapping tool, or override the native frame rate of the clip using Interpret Footage.

You don't have to change the frame rate of the project. But, if you have a 24fps project and use Interpret Footage to change the clip frame rate to 24fps, you will have a one to one correspondence and not have any dropped, added, or frame blended frames. However, if you are going to be eventually using this slowed down footage in a 30fps or other frame rate project, you may as well just use that project framerate.

[Ron Hunter]

OK. All of this has been helpful.

I have 60p footage. I want the finished movie to be in 24p, but I also want the scenes in the movie to be in slow motion. What is the best way to make that happen? Create 60p project, use 40% playback speed with "time stretch", and output as 24p? Or use "time remapping"? Or something else?

[Bob]

In that particular scenario, since you want the finished video to be 24p, I would use a 24p project and use Interpret footage to set the frame rate of the clip to 24 fps.

Add the clip to the project and use Interpret Footage on it before you place it on the timeline. You can still use time remapping if you want it even slower.

[Steve Grisetti]

Exactly what I'd have recommended!

As we've said, the thing to remember is that frame rate has nothing to do with your playback speed. One is a characteristic of your video and the other is a video effect.

[Kent Frost]

This is confusing. You guys are telling him that playback speed has nothing to do with his framerate, which is true but misleading. He said he wanted to achieve slow motion using his 60p footage on a 24p timeline. In which case, playback speed DOES relate. 24 frames per second is 40% of 60. Slowing down his 60p clip to 40% will make it be a slow motion 24p clip. However, any other clips shot at 60p that are not intended for a speed change like that will need to be reinterpreted as a 24p clip, as you've all mentioned.

[Bob]

I don't see how that is misleading, Kent.

The speed of the clip is a function of the clip not the project setting. To change the playback speed of the clip you need to change the rate of the clip -- either directly using Interpret Footage, or indirectly using the Time Stretch/Time Remapping effect. Once changed, the clip will play back at same new speed regardless of the project's frame rate setting.

Ron said "During a recent podcast with Dave Dugdale and "Knoptop", Dave said he likes to shoot in 60p and then play it back in 24p for a smooth slow motion effect. I've seen that effect in his slider videos and I want to try it out, thus the motivation for today's inquiry." Using Interpret Footage on the 60p clip to change it to 24p will do exactly that. And, it will be 40% slower as you pointed out. Furthermore, it will be 40% slower regardless of the project frame rate. He could have just as well used a 60p or 30p project with the same results. He could have used the Time Stretch/Remapping Tool instead of Interpret Footage, but for that he would have needed to calculate the percent change in speed.

While the project frame rate will not affect the playback time, it will affect how the 60p clip is conformed to the project frame rate. Premiere has a number of strategies it can use and depending on the specific rates could add, delete, or frame blend to interpolate between frames. In the special case of a 24p timeline, 60p footage interpreted to 24p does not require any special processing to get conforming frames and it is a clean conversion.

[Kent Frost]

Ron said "During a recent podcast with Dave Dugdale and "Knoptop", Dave said he likes to shoot in 60p and then play it back in 24p for a smooth slow motion effect. I've seen that effect in his slider videos and I want to try it out, thus the motivation for today's inquiry." Using Interpret Footage on the 60p clip to change it to 24p will do exactly that. And, it will be 40% slower as you pointed out. Furthermore, it will be 40% slower regardless of the project frame rate. He could have just as well used a 60p or 30p project with the same results. He could have used the Time Stretch/Remapping Tool instead of Interpret Footage, but for that he would have needed to calculate the percent change in speed.

This goes to show why I shouldn't speak up about programs I don't use. LOL I was going off of the language I knew, without knowing any of it from PRE.