Powershell base64 vs regular base64

Question

I use powershell to convert string

$Text = 'ouser:v3$34@#85b&g%fD79a3nf'
$Bytes = [System.Text.Encoding]::Unicode.GetBytes($Text)
$EncodedText =[Convert]::ToBase64String($Bytes)
$EncodedText 

However when using https://www.base64decode.org/, or some java libraries for base64 encoding I get a different, shorter version.

Sample string:

This is a secret and should be hiden

powershell result:

VABoAGkAcwAgAGkAcwAgAGEAIABzAGUAYwByAGUAdAAgAGEAbgBkACAAcwBoAG8AdQBsAGQAIABiAGUAIABoAGkAZABlAG4A

normal base64 result:

VGhpcyBpcyBhIHNlY3JldCBhbmQgc2hvdWxkIGJlIGhpZGVu

While using the website I am able to decode both versions, however using my java code I am only able to decode the latter. Why is that? Is there more than one version of base64? Where those differences come from?

Solution

Adding the comment from @Raziel as an answer for better discoverability of this question.

[System.Text.Encoding]::Unicode] is UTF-16, the later is UTF-8. There's [System.Text.Encoding]::UTF8 that you can use.