diff --git a/libavfilter/vf_scale.c b/libavfilter/vf_scale.c
index 0348f19d33..f92529e7c8 100644
--- a/libavfilter/vf_scale.c
+++ b/libavfilter/vf_scale.c
@@ -882,10 +882,19 @@ static int process_command(AVFilterContext *ctx, const char *cmd, const char *ar
     return ret;
 }
 
+#if FF_API_CHILD_CLASS_NEXT
 static const AVClass *child_class_next(const AVClass *prev)
 {
     return prev ? NULL : sws_get_class();
 }
+#endif
+
+static const AVClass *child_class_iterate(void **iter)
+{
+    const AVClass *c = *iter ? NULL : sws_get_class();
+    *iter = (void*)(uintptr_t)c;
+    return c;
+}
 
 #define OFFSET(x) offsetof(ScaleContext, x)
 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
@@ -944,7 +953,10 @@ static const AVClass scale_class = {
     .option           = scale_options,
     .version          = LIBAVUTIL_VERSION_INT,
     .category         = AV_CLASS_CATEGORY_FILTER,
+#if FF_API_CHILD_CLASS_NEXT
     .child_class_next = child_class_next,
+#endif
+    .child_class_iterate = child_class_iterate,
 };
 
 static const AVFilterPad avfilter_vf_scale_inputs[] = {
@@ -984,7 +996,10 @@ static const AVClass scale2ref_class = {
     .option           = scale_options,
     .version          = LIBAVUTIL_VERSION_INT,
     .category         = AV_CLASS_CATEGORY_FILTER,
+#if FF_API_CHILD_CLASS_NEXT
     .child_class_next = child_class_next,
+#endif
+    .child_class_iterate = child_class_iterate,
 };
 
 static const AVFilterPad avfilter_vf_scale2ref_inputs[] = {