would there be a workaround for CJK characters filename ?

[kissson]

it comes to ??? when passing to mplayer
so it is always file not found

would it be something like :
dir original_filename.avi /X | tr -s " " | cut -d " " -f 5 | xargs mplayer -
in windows ?

[redxii]

Enable "Pass short filenames (8+3) to MPlayer" in Preferences - Advanced.