diff --git a/libavutil/eval.c b/libavutil/eval.c
index 48832979e2..62d2ae938b 100644
--- a/libavutil/eval.c
+++ b/libavutil/eval.c
@@ -735,6 +735,22 @@ end:
     return ret;
 }
 
+int av_expr_count_vars(AVExpr *e, unsigned *counter, int size)
+{
+    int i;
+
+    if (!e || !counter || !size)
+        return AVERROR(EINVAL);
+
+    for (i = 0; e->type != e_const && i < 3 && e->param[i]; i++)
+        av_expr_count_vars(e->param[i], counter, size);
+
+    if (e->type == e_const && e->a.const_index < size)
+        counter[e->a.const_index]++;
+
+    return 0;
+}
+
 double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)
 {
     Parser p = { 0 };
diff --git a/libavutil/eval.h b/libavutil/eval.h
index dacd22b96e..9bdb10cca2 100644
--- a/libavutil/eval.h
+++ b/libavutil/eval.h
@@ -86,6 +86,16 @@ int av_expr_parse(AVExpr **expr, const char *s,
  */
 double av_expr_eval(AVExpr *e, const double *const_values, void *opaque);
 
+/**
+ * Track the presence of variables and their number of occurrences in a parsed expression
+ *
+ * @param counter a zero-initialized array where the count of each variable will be stored
+ * @param size size of array
+ * @return 0 on success, a negative value indicates that no expression or array was passed
+ * or size was zero
+ */
+int av_expr_count_vars(AVExpr *e, unsigned *counter, int size);
+
 /**
  * Free a parsed expression previously created with av_expr_parse().
  */
diff --git a/libavutil/version.h b/libavutil/version.h
index 27d663baf1..af3abf7265 100644
--- a/libavutil/version.h
+++ b/libavutil/version.h
@@ -79,8 +79,8 @@
  */
 
 #define LIBAVUTIL_VERSION_MAJOR  56
-#define LIBAVUTIL_VERSION_MINOR  35
-#define LIBAVUTIL_VERSION_MICRO 101
+#define LIBAVUTIL_VERSION_MINOR  36
+#define LIBAVUTIL_VERSION_MICRO 100
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \
                                                LIBAVUTIL_VERSION_MINOR, \