Rename files to the folder name. Move all files from subfolders to root. Remove empty folders.

rename-to-folder.sh

# To verify first, just echo instead of move:
for f in */* ; do fp=$(dirname "$f"); ext="${f##*.}" ; echo "$f" "$fp"/"$fp"."$ext" ; done

# Rename for realz:
for f in */* ; do fp=$(dirname "$f"); ext="${f##*.}" ; mv "$f" "$fp"/"$fp"."$ext" ; done

# Move all files to root:
mv *.mkv */*.mkv .

# Delete all empty folders in current directory:
find . -type d -empty -delete