How do you remove blurred spot on a video?

Answer 1

You can take it into a post-processing/compositing application such as After Effects, Shake, Fusion, or Nuke, and possibly even some video editing software (if it has masking and sharpening features) and masking out that area (only this will be visible and effected) then applying whatever sharpening tool your program uses on the masked selection, and layering that on top of the original video. However, you will never be able to pull out additional detail that did not exist in the first place, and sharpening an area will likely create some pixelated artifacts in that area as well; over-sharpening can make it look worse, so this should be applied with subtlety.