--- a/hgext/convert/common.py
+++ b/hgext/convert/common.py
@@ -75,6 +75,8 @@ class converter_source(object):
         if not encoding:
             encoding = self.encoding or 'utf-8'
 
+        if isinstance(s, unicode):
+            return s.encode("utf-8")
         try:
             return s.decode(encoding).encode("utf-8")
         except:

--- a/hgext/convert/subversion.py
+++ b/hgext/convert/subversion.py
@@ -278,7 +278,8 @@ class convert_svn(converter_source):
     def revid(self, revnum, module=None):
         if not module:
             module = self.module
-        return (u"svn:%s%s@%s" % (self.uuid, module, revnum)).decode(self.encoding)
+        return u"svn:%s%s@%s" % (self.uuid, module.decode(self.encoding),
+                                 revnum)
 
     def revnum(self, rev):
         return int(rev.split('@')[-1])