while IFS= read -r -d '' movie ; do
    echo "Found: $movie"

    convert_command="ffmpeg -i '$movie' -vcodec copy -acodec copy '$movie.mp4'"

    if bash -c "$convert_command" ; then
        echo "Converted to mp4"
        #rm "$movie" #Uncomment to remove source file.
    else
        echo "Convertation failed"
    fi
done << (find . -type f -iregex '.*\(mkv\|mpeg\|avi\|wmv\|mov\)' -print0)