macosx: video effects: only set video splitters when needed

Avoids setting this variable multiple times, as each time vout
restart is requested. Also avoids unnecessary vout restarts at
start and when changing profiles.

refs #12063

(cherry picked from commit ddccf6b050412f348a00c12b857a48d4ac5e2b63)
Signed-off-by: Felix Paul Kühne <fkuehne@videolan.org>

modules/gui/macosx/VideoEffects.m

@@ -594,9 +594,6 @@ static VLCVideoEffects *_o_sharedInstance = nil;
         vlc_object_release(p_vout);
     }
 
-    // video-splitter needs to be set via playlist var
-    var_SetString(pl_Get(p_intf), "video-splitter", "");
-
     /* fetch preset */
     NSArray *items = [[[defaults objectForKey:@"VideoEffectProfiles"] objectAtIndex:selectedProfile] componentsSeparatedByString:@";"];
 
@@ -633,12 +630,13 @@ static VLCVideoEffects *_o_sharedInstance = nil;
 
     tempString = B64DecNSStr([items objectAtIndex:2]);
     /* enable another round of new filters */
-    config_PutPsz(p_intf,"video-splitter", "");
-    if ([tempString length] > 0) {
-        tempArray = [tempString componentsSeparatedByString:@":"];
-        count = [tempArray count];
-        for (NSUInteger x = 0; x < count; x++)
-            [vci_si setVideoFilter:[[tempArray objectAtIndex:x] UTF8String] on:YES];
+    char *psz_current_splitter = var_GetString(pl_Get(p_intf), "video-splitter");
+    bool b_filter_changed = ![tempString isEqual:toNSStr(psz_current_splitter)];
+    free(psz_current_splitter);
+
+    if (b_filter_changed) {
+        config_PutPsz(p_intf, "video-splitter", [tempString UTF8String]);
+        var_SetString(pl_Get(p_intf), "video-splitter", [tempString UTF8String]);
     }
 
     /* try to set filter values on-the-fly and store them appropriately */