Lately I’ve been trying out some looping webp animations. My source material is at 25 fps.
Now, when I load a clip into a 25 fps project, change the speed of the clip to 0,7 and export it as a webp animation with 17.5 fps, will I get a “smooth” slow motion clip? Meaning, will every frame of my 25 fps source clip be turned into one frame of my exported slow-motion animation?
Or will it be “messed up” as in the changing of the clip’s speed some frames will be duplicated, and from that, while exporting at a slower frame rate, some frames will be skipped over?
I don’t know how this works. I’m using the Lanczos interpolation setting, if that is of any importance in this matter.
The only way to get smooth slow motion without advanced image processing techniques or AI is when the source frame rate is higher than the project and then you slow it down. For example, 50 fps in a 25 fps project at half speed will use every frame from the source. Otherwise, 50 in 25 uses every other frame. Basically, that is all that Shotcut offers outside of a poor alternative that entails using Properties > Convert > Advanced > Override frame rate with Frame rate conversion = Motion Compensation option to artificially increase the frame rate of the source. However, that is not available for animated webp in Shotcut. You could convert the WebP to video and then do it. The Interpolation options in Shotcut will have no effect on this process unless you are also changing resolution.
So in my example, when I decide that I want to make a 0,7 speed slow-mo of that clip, for the best result I’d have to start a new 17,5 fps project and import the clip into that. Or, generally speaking, the project should be in the target frame rate so the source’s frames will neatly fit into the project’s frames.
Since I’m using templates for a variety of aspect ratios I guess I’ll have to create a whole bunch of custom video modes. But I just found out that I can change the video mode of an active project, which is something.
I may also try out the poor alternative. My source files are not webp, I only export as looping webp animations so I can post them, as a better alternative to a gif file, in forums.
Thank you for the help, now I know why some of my webp look so jerky.
Maybe “smooth” is the wrong word here, but that limitation comes with my source material. The low number of source frames is exactly why I want to avoid the skippiing over (or duplicating) of frames, to make the motions as smooth as possible with so few frames.
Give it a try and decide