Base64 encoding applied to different unicode texts always yields different base64 texts ... true or false?

[Costello, Roger L. via Unicode]

Hi Unicode Experts,

Suppose base64 encoding is applied to m to yield base64 text t. 

Next, suppose base64 encoding is applied to m' to yield base64 text t'.

If m is not equal to m', then t will not equal t'.

In other words, given different inputs, base64 encoding always yields different base64 texts.

True or false?

How about the opposite direction: If m is base64 encoded to yield t and then t is base64 decoded to yield n, will it always be the case that m equals n?

/Roger