diff --git a/doc/writing_filters.txt b/doc/writing_filters.txt
index 98b9c6f3d2..2e25cbed71 100644
--- a/doc/writing_filters.txt
+++ b/doc/writing_filters.txt
@@ -389,7 +389,7 @@ distributor with something like this:
 
     td.in  = in;
     td.out = out;
-    ctx->internal->execute(ctx, filter_slice, &td, NULL, FFMIN(outlink->h, ctx->graph->nb_threads));
+    ctx->internal->execute(ctx, filter_slice, &td, NULL, FFMIN(outlink->h, ff_filter_get_nb_threads(ctx)));
 
     // ...