diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index fce930360d..f1f6994574 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -358,12 +358,12 @@ OBJS-$(CONFIG_ROBERTS_OPENCL_FILTER)         += vf_convolution_opencl.o opencl.o
                                                 opencl/convolution.o
 OBJS-$(CONFIG_ROTATE_FILTER)                 += vf_rotate.o
 OBJS-$(CONFIG_SAB_FILTER)                    += vf_sab.o
-OBJS-$(CONFIG_SCALE_FILTER)                  += vf_scale.o scale.o
+OBJS-$(CONFIG_SCALE_FILTER)                  += vf_scale.o
 OBJS-$(CONFIG_SCALE_CUDA_FILTER)             += vf_scale_cuda.o vf_scale_cuda.ptx.o
 OBJS-$(CONFIG_SCALE_NPP_FILTER)              += vf_scale_npp.o scale.o
 OBJS-$(CONFIG_SCALE_QSV_FILTER)              += vf_scale_qsv.o
 OBJS-$(CONFIG_SCALE_VAAPI_FILTER)            += vf_scale_vaapi.o scale.o vaapi_vpp.o
-OBJS-$(CONFIG_SCALE2REF_FILTER)              += vf_scale.o scale.o
+OBJS-$(CONFIG_SCALE2REF_FILTER)              += vf_scale.o
 OBJS-$(CONFIG_SCROLL_FILTER)                 += vf_scroll.o
 OBJS-$(CONFIG_SELECT_FILTER)                 += f_select.o
 OBJS-$(CONFIG_SELECTIVECOLOR_FILTER)         += vf_selectivecolor.o
diff --git a/libavfilter/scale.c b/libavfilter/scale.c
index eaee95fac6..668aa04622 100644
--- a/libavfilter/scale.c
+++ b/libavfilter/scale.c
@@ -60,49 +60,6 @@ enum var_name {
     VARS_NB
 };
 
-/**
- * This must be kept in sync with var_names so that it is always a
- * complete list of var_names with the scale2ref specific names
- * appended. scale2ref values must appear in the order they appear
- * in the var_name_scale2ref enum but also be below all of the
- * non-scale2ref specific values.
- */
-static const char *const var_names_scale2ref[] = {
-    "PI",
-    "PHI",
-    "E",
-    "in_w",   "iw",
-    "in_h",   "ih",
-    "out_w",  "ow",
-    "out_h",  "oh",
-    "a",
-    "sar",
-    "dar",
-    "hsub",
-    "vsub",
-    "ohsub",
-    "ovsub",
-    "main_w",
-    "main_h",
-    "main_a",
-    "main_sar",
-    "main_dar", "mdar",
-    "main_hsub",
-    "main_vsub",
-    NULL
-};
-
-enum var_name_scale2ref {
-    VAR_S2R_MAIN_W,
-    VAR_S2R_MAIN_H,
-    VAR_S2R_MAIN_A,
-    VAR_S2R_MAIN_SAR,
-    VAR_S2R_MAIN_DAR, VAR_S2R_MDAR,
-    VAR_S2R_MAIN_HSUB,
-    VAR_S2R_MAIN_VSUB,
-    VARS_S2R_NB
-};
-
 int ff_scale_eval_dimensions(void *log_ctx,
     const char *w_expr, const char *h_expr,
     AVFilterLink *inlink, AVFilterLink *outlink,
@@ -115,16 +72,7 @@ int ff_scale_eval_dimensions(void *log_ctx,
     int factor_w, factor_h;
     int eval_w, eval_h;
     int ret;
-    const char scale2ref = outlink->src->nb_inputs == 2 && outlink->src->inputs[1] == inlink;
-    double var_values[VARS_NB + VARS_S2R_NB], res;
-    const AVPixFmtDescriptor *main_desc;
-    const AVFilterLink *main_link;
-    const char *const *names = scale2ref ? var_names_scale2ref : var_names;
-
-    if (scale2ref) {
-        main_link = outlink->src->inputs[0];
-        main_desc = av_pix_fmt_desc_get(main_link->format);
-    }
+    double var_values[VARS_NB], res;
 
     var_values[VAR_PI]    = M_PI;
     var_values[VAR_PHI]   = M_PHI;
@@ -142,32 +90,20 @@ int ff_scale_eval_dimensions(void *log_ctx,
     var_values[VAR_OHSUB] = 1 << out_desc->log2_chroma_w;
     var_values[VAR_OVSUB] = 1 << out_desc->log2_chroma_h;
 
-    if (scale2ref) {
-        var_values[VARS_NB + VAR_S2R_MAIN_W] = main_link->w;
-        var_values[VARS_NB + VAR_S2R_MAIN_H] = main_link->h;
-        var_values[VARS_NB + VAR_S2R_MAIN_A] = (double) main_link->w / main_link->h;
-        var_values[VARS_NB + VAR_S2R_MAIN_SAR] = main_link->sample_aspect_ratio.num ?
-            (double) main_link->sample_aspect_ratio.num / main_link->sample_aspect_ratio.den : 1;
-        var_values[VARS_NB + VAR_S2R_MAIN_DAR] = var_values[VARS_NB + VAR_S2R_MDAR] =
-            var_values[VARS_NB + VAR_S2R_MAIN_A] * var_values[VARS_NB + VAR_S2R_MAIN_SAR];
-        var_values[VARS_NB + VAR_S2R_MAIN_HSUB] = 1 << main_desc->log2_chroma_w;
-        var_values[VARS_NB + VAR_S2R_MAIN_VSUB] = 1 << main_desc->log2_chroma_h;
-    }
-
     /* evaluate width and height */
     av_expr_parse_and_eval(&res, (expr = w_expr),
-                           names, var_values,
+                           var_names, var_values,
                            NULL, NULL, NULL, NULL, NULL, 0, log_ctx);
     eval_w = var_values[VAR_OUT_W] = var_values[VAR_OW] = (int) res == 0 ? inlink->w : (int) res;
 
     if ((ret = av_expr_parse_and_eval(&res, (expr = h_expr),
-                                      names, var_values,
+                                      var_names, var_values,
                                       NULL, NULL, NULL, NULL, NULL, 0, log_ctx)) < 0)
         goto fail;
     eval_h = var_values[VAR_OUT_H] = var_values[VAR_OH] = (int) res == 0 ? inlink->h : (int) res;
     /* evaluate again the width, as it may depend on the output height */
     if ((ret = av_expr_parse_and_eval(&res, (expr = w_expr),
-                                      names, var_values,
+                                      var_names, var_values,
                                       NULL, NULL, NULL, NULL, NULL, 0, log_ctx)) < 0)
         goto fail;
     eval_w = (int) res == 0 ? inlink->w : (int) res;
diff --git a/libavfilter/vf_scale.c b/libavfilter/vf_scale.c
index 41ddec7661..e7d52faccc 100644
--- a/libavfilter/vf_scale.c
+++ b/libavfilter/vf_scale.c
@@ -29,9 +29,9 @@
 #include "avfilter.h"
 #include "formats.h"
 #include "internal.h"
-#include "scale.h"
 #include "video.h"
 #include "libavutil/avstring.h"
+#include "libavutil/eval.h"
 #include "libavutil/internal.h"
 #include "libavutil/mathematics.h"
 #include "libavutil/opt.h"
@@ -41,6 +41,85 @@
 #include "libavutil/avassert.h"
 #include "libswscale/swscale.h"
 
+static const char *const var_names[] = {
+    "PI",
+    "PHI",
+    "E",
+    "in_w",   "iw",
+    "in_h",   "ih",
+    "out_w",  "ow",
+    "out_h",  "oh",
+    "a",
+    "sar",
+    "dar",
+    "hsub",
+    "vsub",
+    "ohsub",
+    "ovsub",
+    NULL
+};
+
+enum var_name {
+    VAR_PI,
+    VAR_PHI,
+    VAR_E,
+    VAR_IN_W,   VAR_IW,
+    VAR_IN_H,   VAR_IH,
+    VAR_OUT_W,  VAR_OW,
+    VAR_OUT_H,  VAR_OH,
+    VAR_A,
+    VAR_SAR,
+    VAR_DAR,
+    VAR_HSUB,
+    VAR_VSUB,
+    VAR_OHSUB,
+    VAR_OVSUB,
+    VARS_NB
+};
+
+/**
+ * This must be kept in sync with var_names so that it is always a
+ * complete list of var_names with the scale2ref specific names
+ * appended. scale2ref values must appear in the order they appear
+ * in the var_name_scale2ref enum but also be below all of the
+ * non-scale2ref specific values.
+ */
+static const char *const var_names_scale2ref[] = {
+    "PI",
+    "PHI",
+    "E",
+    "in_w",   "iw",
+    "in_h",   "ih",
+    "out_w",  "ow",
+    "out_h",  "oh",
+    "a",
+    "sar",
+    "dar",
+    "hsub",
+    "vsub",
+    "ohsub",
+    "ovsub",
+    "main_w",
+    "main_h",
+    "main_a",
+    "main_sar",
+    "main_dar", "mdar",
+    "main_hsub",
+    "main_vsub",
+    NULL
+};
+
+enum var_name_scale2ref {
+    VAR_S2R_MAIN_W,
+    VAR_S2R_MAIN_H,
+    VAR_S2R_MAIN_A,
+    VAR_S2R_MAIN_SAR,
+    VAR_S2R_MAIN_DAR, VAR_S2R_MDAR,
+    VAR_S2R_MAIN_HSUB,
+    VAR_S2R_MAIN_VSUB,
+    VARS_S2R_NB
+};
+
 enum EvalMode {
     EVAL_MODE_INIT,
     EVAL_MODE_FRAME,
@@ -218,6 +297,115 @@ static const int *parse_yuv_type(const char *s, enum AVColorSpace colorspace)
     return sws_getCoefficients(colorspace);
 }
 
+static int scale_eval_dimensions(void *log_ctx,
+    const char *w_expr, const char *h_expr,
+    AVFilterLink *inlink, AVFilterLink *outlink,
+    int *ret_w, int *ret_h)
+{
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
+    const AVPixFmtDescriptor *out_desc = av_pix_fmt_desc_get(outlink->format);
+    const char *expr;
+    int w, h;
+    int factor_w, factor_h;
+    int eval_w, eval_h;
+    int ret;
+    const char scale2ref = outlink->src->nb_inputs == 2 && outlink->src->inputs[1] == inlink;
+    double var_values[VARS_NB + VARS_S2R_NB], res;
+    const AVPixFmtDescriptor *main_desc;
+    const AVFilterLink *main_link;
+    const char *const *names = scale2ref ? var_names_scale2ref : var_names;
+
+    if (scale2ref) {
+        main_link = outlink->src->inputs[0];
+        main_desc = av_pix_fmt_desc_get(main_link->format);
+    }
+
+    var_values[VAR_PI]    = M_PI;
+    var_values[VAR_PHI]   = M_PHI;
+    var_values[VAR_E]     = M_E;
+    var_values[VAR_IN_W]  = var_values[VAR_IW] = inlink->w;
+    var_values[VAR_IN_H]  = var_values[VAR_IH] = inlink->h;
+    var_values[VAR_OUT_W] = var_values[VAR_OW] = NAN;
+    var_values[VAR_OUT_H] = var_values[VAR_OH] = NAN;
+    var_values[VAR_A]     = (double) inlink->w / inlink->h;
+    var_values[VAR_SAR]   = inlink->sample_aspect_ratio.num ?
+        (double) inlink->sample_aspect_ratio.num / inlink->sample_aspect_ratio.den : 1;
+    var_values[VAR_DAR]   = var_values[VAR_A] * var_values[VAR_SAR];
+    var_values[VAR_HSUB]  = 1 << desc->log2_chroma_w;
+    var_values[VAR_VSUB]  = 1 << desc->log2_chroma_h;
+    var_values[VAR_OHSUB] = 1 << out_desc->log2_chroma_w;
+    var_values[VAR_OVSUB] = 1 << out_desc->log2_chroma_h;
+
+    if (scale2ref) {
+        var_values[VARS_NB + VAR_S2R_MAIN_W] = main_link->w;
+        var_values[VARS_NB + VAR_S2R_MAIN_H] = main_link->h;
+        var_values[VARS_NB + VAR_S2R_MAIN_A] = (double) main_link->w / main_link->h;
+        var_values[VARS_NB + VAR_S2R_MAIN_SAR] = main_link->sample_aspect_ratio.num ?
+            (double) main_link->sample_aspect_ratio.num / main_link->sample_aspect_ratio.den : 1;
+        var_values[VARS_NB + VAR_S2R_MAIN_DAR] = var_values[VARS_NB + VAR_S2R_MDAR] =
+            var_values[VARS_NB + VAR_S2R_MAIN_A] * var_values[VARS_NB + VAR_S2R_MAIN_SAR];
+        var_values[VARS_NB + VAR_S2R_MAIN_HSUB] = 1 << main_desc->log2_chroma_w;
+        var_values[VARS_NB + VAR_S2R_MAIN_VSUB] = 1 << main_desc->log2_chroma_h;
+    }
+
+    /* evaluate width and height */
+    av_expr_parse_and_eval(&res, (expr = w_expr),
+                           names, var_values,
+                           NULL, NULL, NULL, NULL, NULL, 0, log_ctx);
+    eval_w = var_values[VAR_OUT_W] = var_values[VAR_OW] = (int) res == 0 ? inlink->w : (int) res;
+
+    if ((ret = av_expr_parse_and_eval(&res, (expr = h_expr),
+                                      names, var_values,
+                                      NULL, NULL, NULL, NULL, NULL, 0, log_ctx)) < 0)
+        goto fail;
+    eval_h = var_values[VAR_OUT_H] = var_values[VAR_OH] = (int) res == 0 ? inlink->h : (int) res;
+    /* evaluate again the width, as it may depend on the output height */
+    if ((ret = av_expr_parse_and_eval(&res, (expr = w_expr),
+                                      names, var_values,
+                                      NULL, NULL, NULL, NULL, NULL, 0, log_ctx)) < 0)
+        goto fail;
+    eval_w = (int) res == 0 ? inlink->w : (int) res;
+
+    w = eval_w;
+    h = eval_h;
+
+    /* Check if it is requested that the result has to be divisible by a some
+     * factor (w or h = -n with n being the factor). */
+    factor_w = 1;
+    factor_h = 1;
+    if (w < -1) {
+        factor_w = -w;
+    }
+    if (h < -1) {
+        factor_h = -h;
+    }
+
+    if (w < 0 && h < 0) {
+        w = inlink->w;
+        h = inlink->h;
+    }
+
+    /* Make sure that the result is divisible by the factor we determined
+     * earlier. If no factor was set, it is nothing will happen as the default
+     * factor is 1 */
+    if (w < 0)
+        w = av_rescale(h, inlink->w, inlink->h * factor_w) * factor_w;
+    if (h < 0)
+        h = av_rescale(w, inlink->h, inlink->w * factor_h) * factor_h;
+
+    *ret_w = w;
+    *ret_h = h;
+
+    return 0;
+
+fail:
+    av_log(log_ctx, AV_LOG_ERROR,
+           "Error when evaluating the expression '%s'.\n"
+           "Maybe the expression for out_w:'%s' or for out_h:'%s' is self-referencing.\n",
+           expr, w_expr, h_expr);
+    return ret;
+}
+
 static int config_props(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
@@ -231,7 +419,7 @@ static int config_props(AVFilterLink *outlink)
     int w, h;
     int ret;
 
-    if ((ret = ff_scale_eval_dimensions(ctx,
+    if ((ret =    scale_eval_dimensions(ctx,
                                         scale->w_expr, scale->h_expr,
                                         inlink, outlink,
                                         &w, &h)) < 0)
