Modifying the footage frame rate

- When working with video, it's often not going to be the exact speed that you need. There are many different causes for this, but we can adjust how a video file plays back. Remember, at its heart, video is a series of still images played back in rapid succession. Sometimes you capture at the exact rate that you need for delivery. Other times, the frame rates are different. Let's walk through some of the options when you don't have the right frame rate. Now, I've got several clips here, but we're going to tackle a simple example here, and this is modifying the frame rate of footage. You'll see here we have a clip that's 24 frames per second and one that's 15 frames per second. After Effects makes this pretty easy. Let's open up the project here, and you'll see that there's a couple of sequences set up. Let's start with that 15 frames per second clip, and if we look at that, you see it plays back. Now, under the Composition Settings, you can make a few adjustments. Currently, this is set to a frame rate of 15 frames per second, but let's say you needed to put this into another video project, and it needed to be 30 frames per second, or the more common 29.97. When you turn this on, you're going to notice that things start to look a little bit stuttered. That's because it's repeating. Let's in fact go all the way up to an even higher frame rate of 59.94. Now, it should be quite visible the choppiness of the video. If we go through and step through, you'll notice that a frame holds for one, two, three, four, then it switches. This means that each frame is being repeated. In order to fill the space, After Effects simply duplicates the frame and holds it. Now, you do have some important options. What we can do here is turn on a choice here for frame blending. Just turn on the global switch here to enable frame blending, and then you have a switch down here. The first mode is a draft quality mode, and what this does is blends the frames together. You can see, for example, that it's layering them in with opacity. Think of it this way. In this case, we're spreading out each frame over four subsequent frames, so the first frame is just the original frame. Next, it takes some of the incoming frame and layers that on at low opacity. Then, a little bit more, building up to a gradual blend where now this frame is whole. It's essentially mixing them together. If we play this back, you'll see that it doesn't look quite as choppy anymore. By doing that frame blending of blending the adjacent frames together, the motion effects look a lot smoother. Now, there is one other option, and that is advanced frame blending. If you click this, it's going to do a morph in between things. The challenge is it may not look good. In this case, because it's so fluid, the morph tends to really distort the footage and it looks very wobbly, and really kind of trippy, so I'd be careful with this option on some footage types. Remember, you can toggle between the choices here: No blending, standard frame blending, and advanced frame blending. Now, let's try another clip, this case where it's more traditional video. You see that it's 23.976. Well, let's drop that into a composition, but maybe this needed to be resampled for broadcast, so I can go from 24p, and in the Composition Settings, switch this to 29.97. Now, the clip doesn't change duration. The audio will stay in sync, and everything's a bit longer. Let's play this back. - Rob. - I never thought getting out of debt would be so hard. - [Man] Mike, go Mike. - Sounded perfect. I did everything they told me to do. - They never paid my creditors. They didn't-- - [Instructor] You see here in the movement, what's happening is it's repeating some frames, so as we step through here, you'll notice that occasionally, it holds. One, two, three, four, five is a hold, then it starts to move. In this case, After Effects is taking the fourth frame and holds onto it to pad things out. Now, to the naked eye, you might never notice that, but if you want better results, you can turn on frame blending. Let's take a look at the standard frame blending here, and I'll step through, and you'll notice that it does a little bit of a dissolve there to smooth things out, so as it's moving, by gentle opacity blends, it's able to blend those together for smoother motion. If you want the maximum quality, you can go to the advanced frame blending, or morphing. Now, every single frame has the potential to be crisp. Remember, if there's a lot of movement in the clip, or a lot of motion blur, it might look awkward. But in this case, advanced frame blending really does a nice job on this panning shot. The camera was on a piece of dolly track that was curved, and the movement was smooth. By using advanced frame blending here, we were easily able to retime the shot, keeping maximum crispness in the new clip that's been stretched to compensate for the additional frame rate, but it's given us excellent quality on all of the movement. Every frame is crisp and smooth. The duration matches the original, but the frame rate has been adjusted to match the delivery spec, in this case, going from 24p to 29.97. All the audio's in sync. There's no loss in image quality. All you take is the processing time to do the advanced frame conversion.