How to change time stamp recorded in the audit log to normal format ?

Issue

• How to change the unix timestamp in audit log to normal format:

  # cat /var/log/audit/audit.log
  type=USER_LOGIN msg=audit(1431921715.378:17): user pid=2222 uid=0 auid=4294967295 ses=4294967295 msg='op=login id=0 exe="/bin/login" hostname=? addr=? terminal=tty1 res=failed'
  (In this case ,the question is how to change unix timestamp "1431921715.378:17" to normal format.)