Use NULL instead of magic string to flag unset parameter

diff --git a/src/modules/core/filter_brightness.c b/src/modules/core/filter_brightness.c
index aeb765427a957ea34b69f23dc477e45d6be9a02d..be06e432ea05ee2abe3bb5929d430e7e92007782 100644 (file)
--- a/src/modules/core/filter_brightness.c
+++ b/src/modules/core/filter_brightness.c
@@ -27,7 +27,6 @@
 #include <string.h>
 
 #define CLAMP( x, min, max ) (x) < (min) ? (min) : (x) > (max) ? (max) : (x)
-#define UNSET "unset"
 
 /** Do it :-).
 */
@@ -50,7 +49,7 @@ static int filter_get_image( mlt_frame frame, uint8_t **image, mlt_image_format
 
                // Use animated "level" property only if it has been set since init
                char* level_property = mlt_properties_get( MLT_FILTER_PROPERTIES( filter ), "level" );
-               if ( strcmp( level_property, UNSET ) != 0 )
+               if ( level_property != NULL )
                {
                        level = mlt_properties_anim_get_double( properties, "level", position, length );
                }
@@ -110,7 +109,7 @@ mlt_filter filter_brightness_init( mlt_profile profile, mlt_service_type type, c
        {
                filter->process = filter_process;
                mlt_properties_set( MLT_FILTER_PROPERTIES( filter ), "start", arg == NULL ? "1" : arg );
-               mlt_properties_set( MLT_FILTER_PROPERTIES( filter ), "level", UNSET );
+               mlt_properties_set( MLT_FILTER_PROPERTIES( filter ), "level", NULL );
        }
        return filter;
 }