Consider the following two ways to generate a SHA512 password hash:

console.log(require("crypto").createHash("sha512").update("mysalt" + "mypassword").digest("base64"));

output:

yarunhSR9I6yzZYCn8KL/WINjXAFzFeS35Z2ykbaO0h8bY7mnkRSYcY+HfJYLA35XtuOSC8lIGOyssUUerTuhw==

openssl passwd -6 -salt mysalt mypassword

output:

$6$mysalt$Ts3752w7WPBw6ENoJhmynzPn47RFb2ze39cgq94y81EGSOvtYpxE6Tatj3ZREJqN5Qn.lBw7wL81kAod63xb5/

The outputs are very different – even if the $6$mysalt$ part from the second output is ignored.

1. Is it only a matter of encoding or something more?
2. Is it possible to derive one format from the other (by re-encoding etc.)?