Fix crash generating avformat metadata.

diff --git a/src/modules/avformat/factory.c b/src/modules/avformat/factory.c
index 3d7bf6bebda058696d357f5d26953bcf3d2ddc49..ab62007b12c699768d457b15c737a97815a20e18 100644 (file)
--- a/src/modules/avformat/factory.c
+++ b/src/modules/avformat/factory.c
@@ -174,19 +174,21 @@ static void add_parameters( mlt_properties params, void *object, int req_flags,
 
                // Add the parameter metadata for this AVOption.
                mlt_properties_set( p, "identifier", opt->name );
-               if ( subclass )
+               if ( opt->help )
                {
-                       char *s = malloc( strlen( opt->help ) + strlen( subclass ) + 4 );
-                       strcpy( s, opt->help );
-                       strcat( s, " (" );
-                       strcat( s, subclass );
-                       strcat( s, ")" );
-                       mlt_properties_set( p, "description", s );
-                       free( s );
+                       if ( subclass )
+                       {
+                               char *s = malloc( strlen( opt->help ) + strlen( subclass ) + 4 );
+                               strcpy( s, opt->help );
+                               strcat( s, " (" );
+                               strcat( s, subclass );
+                               strcat( s, ")" );
+                               mlt_properties_set( p, "description", s );
+                               free( s );
+                       }
+                       else
+                               mlt_properties_set( p, "description", opt->help );
                }
-               else
-                       mlt_properties_set( p, "description", opt->help );
-
 
         switch ( opt->type )
                {