The left image was created with interpolation by the computer, which creates 25 frames per second by analyzing the 16 of 18 frames per second originally shot.
On the right, the blending keeps the 16 or 18 frames per second and adds 9 or 7 frames per second by generating a fade between some of the adjacent frames.
Look at the preview frame, and in particular the position of the racket, both in the left and right window.
On the right, the blending has generated a fade between two adjacent frames, so you can see two faded racquets.
On the left, the computer has calculated the position of the racket by placing it in the middle of the trajectory that starts from the previous frame and ends in the next one. The image is incredibly realistic: there are no blurring and annoying fades of the racket, nor of the tennis player and the audience in the background.
In reality, that frame is entirely computer generated and the scene in that moment never existed, although its creation objectively reproduces what happened in that moment.
So far the interpolation method is extraordinary and it seems like science fiction.
However, there were some parts where the computer created unacceptable artifacts. This is why blending is used to digitize 8 mm films: it creates videos a little bit jerky, but there are no excessively damaged segments.
Back to my workflow—after digitizing the film with the scanner, I export a movie at the number of frames per second that I decide, still without producing the “overlapping frames” that can be seen in the right part of the window of the film above; only in the next phase, the restoration, the images are brought back to the actual speed.
I know these are very technical notions. I’m a technician who took years to understand what equipment and workflows to use to create the best videos from 8 mm and super 8 films. But you don't need to learn everything I’m explaining if you just want to extract a photo from a video.You need a professional editor to do this job for you.
The software I mentioned, FF Transcode, once allowed the user to export a sequence of frames in the the following formats:
In the latest versions its creators have eliminated that option for several reasons.
The first is that sometimes artifacts were created. This was a problem generated by that specific software.