Possible bug with mp4decrypt and save-name

[tarantn]

I think there might be a bug when using mp4decrypt and a save-name with accented characters.
This does not occur when using shaka-packager or a save-name without those accented characters and mp4decrypt.

Example of a command where no decryption happens:

N_m3u8DL-RE.exe MPD_URL --key KID:KEY --save-name "étest" --mp4-real-time-decryption --live-real-time-merge

I know that shaka-packager should be prefered over mp4decrypt in this case as you show in the log
"WARN : When enabling real-time decryption, it is recommended to use shaka-packager instead of mp4decrypt"

[tintanto]

This bug is still there sadly. Also, the same for asian letters.