diff --git a/libavfilter/avfilter.c b/libavfilter/avfilter.c
index 32e0944102..6157521ab3 100644
--- a/libavfilter/avfilter.c
+++ b/libavfilter/avfilter.c
@@ -47,6 +47,27 @@ void avfilter_unref_pic(AVFilterPicRef *ref)
     av_free(ref);
 }
 
+void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
+                         AVFilterPad **pads, AVFilterLink ***links,
+                         AVFilterPad *newpad)
+{
+    unsigned i;
+
+    idx = FFMIN(idx, *count);
+
+    *pads  = av_realloc(*pads,  sizeof(AVFilterPad)   * (*count + 1));
+    *links = av_realloc(*links, sizeof(AVFilterLink*) * (*count + 1));
+    memmove(*pads +idx+1, *pads +idx, sizeof(AVFilterPad)   * (*count-idx));
+    memmove(*links+idx+1, *links+idx, sizeof(AVFilterLink*) * (*count-idx));
+    memcpy(*pads+idx, newpad, sizeof(AVFilterPad));
+    (*links)[idx] = NULL;
+
+    (*count) ++;
+    for(i = idx+1; i < *count; i ++)
+        if(*links[i])
+            (*(unsigned *)((uint8_t *)(*links[i]) + padidx_off)) ++;
+}
+
 int avfilter_link(AVFilterContext *src, unsigned srcpad,
                   AVFilterContext *dst, unsigned dstpad)
 {