No full selection possible

[BinaryHammer]

If you have a video that is already 4 seconds or less long, it is not possible so select the whole length of the video as source. So you get only a selection of an already very short video.
For example a 1 second video. I could not create a Live Photo with a 1 second video, because the selection allows only part of the given video.

[BinaryHammer]

I found out, that the time stamp of the selected frame can severely limit the duration of the video. Even if you have a long video.
Selecting a frame near zero, will only grant you a video size of 0.03 seconds before the frame, but only half a second after the frame. Even though the Video is 4s long.