diff --git a/lib/Subtitle/BASE.pm b/lib/Subtitle/BASE.pm
index bdfc912..542b0b6 100644
--- a/lib/Subtitle/BASE.pm
+++ b/lib/Subtitle/BASE.pm
@@ -26,3 +26,35 @@ sub parse { return "Unimplemented by subclass"; }
 sub build { return "Unimplemented by subclass"; }
 
 1;
+
+=pod
+
+=head1 NAME
+
+Subtitle::BASE -- base class of subtitle file
+
+=head1 SYNOPSYS
+
+  use base 'Subtitle::BASE';
+
+This module should not be used directly.
+
+=head1 METHODS
+
+=head2 C<log>
+
+  $obj->log(warn => "something happens");
+
+Add some info to processing log.
+Takes two args: message level (debug/info/warn/error) and message text
+
+Collected messages can be accessed like this:
+
+  my @log = @{ $obj->{log} };
+
+=head C<build>
+=head C<parse>
+
+Stubs for subclasses
+
+=cut