diff --git a/player/lua.c b/player/lua.c
index 9fe1d0deca..04c7dbb977 100644
--- a/player/lua.c
+++ b/player/lua.c
@@ -974,17 +974,7 @@ static int script_set_osd_ass(lua_State *L)
     return 0;
 }
 
-static int script_get_osd_resolution(lua_State *L)
-{
-    struct MPContext *mpctx = get_mpctx(L);
-    int w, h;
-    osd_object_get_resolution(mpctx->osd, OSDTYPE_EXTERNAL, &w, &h);
-    lua_pushnumber(L, w);
-    lua_pushnumber(L, h);
-    return 2;
-}
-
-static int script_get_screen_size(lua_State *L)
+static int script_get_osd_size(lua_State *L)
 {
     struct MPContext *mpctx = get_mpctx(L);
     struct mp_osd_res vo_res = osd_get_vo_res(mpctx->osd, OSDTYPE_EXTERNAL);
@@ -996,7 +986,7 @@ static int script_get_screen_size(lua_State *L)
     return 3;
 }
 
-static int script_get_screen_margins(lua_State *L)
+static int script_get_osd_margins(lua_State *L)
 {
     struct MPContext *mpctx = get_mpctx(L);
     struct mp_osd_res vo_res = osd_get_vo_res(mpctx->osd, OSDTYPE_EXTERNAL);
@@ -1012,10 +1002,8 @@ static int script_get_mouse_pos(lua_State *L)
     struct MPContext *mpctx = get_mpctx(L);
     int px, py;
     mp_input_get_mouse_pos(mpctx->input, &px, &py);
-    double sw, sh;
-    osd_object_get_scale_factor(mpctx->osd, OSDTYPE_EXTERNAL, &sw, &sh);
-    lua_pushnumber(L, px * sw);
-    lua_pushnumber(L, py * sh);
+    lua_pushnumber(L, px);
+    lua_pushnumber(L, py);
     return 2;
 }
 
@@ -1030,14 +1018,11 @@ static int script_input_set_section_mouse_area(lua_State *L)
 {
     struct MPContext *mpctx = get_mpctx(L);
 
-    double sw, sh;
-    osd_object_get_scale_factor(mpctx->osd, OSDTYPE_EXTERNAL, &sw, &sh);
-
     char *section = (char *)luaL_checkstring(L, 1);
-    int x0 = sw ? luaL_checkinteger(L, 2) / sw : 0;
-    int y0 = sh ? luaL_checkinteger(L, 3) / sh : 0;
-    int x1 = sw ? luaL_checkinteger(L, 4) / sw : 0;
-    int y1 = sh ? luaL_checkinteger(L, 5) / sh : 0;
+    int x0 = luaL_checkinteger(L, 2);
+    int y0 = luaL_checkinteger(L, 3);
+    int x1 = luaL_checkinteger(L, 4);
+    int y1 = luaL_checkinteger(L, 5);
     mp_input_set_section_mouse_area(mpctx->input, section, x0, y0, x1, y1);
     return 0;
 }
@@ -1266,9 +1251,8 @@ static const struct fn_entry main_fns[] = {
     FN_ENTRY(raw_observe_property),
     FN_ENTRY(raw_unobserve_property),
     FN_ENTRY(set_osd_ass),
-    FN_ENTRY(get_osd_resolution),
-    FN_ENTRY(get_screen_size),
-    FN_ENTRY(get_screen_margins),
+    FN_ENTRY(get_osd_size),
+    FN_ENTRY(get_osd_margins),
     FN_ENTRY(get_mouse_pos),
     FN_ENTRY(get_time),
     FN_ENTRY(input_set_section_mouse_area),
diff --git a/player/lua/osc.lua b/player/lua/osc.lua
index 24afeef970..f3beee85dd 100644
--- a/player/lua/osc.lua
+++ b/player/lua/osc.lua
@@ -99,6 +99,27 @@ local state = {
 -- Helperfunctions
 --
 
+-- scale factor for translating between real and virtual ASS coordinates
+function get_virt_scale_factor()
+    local w, h = mp.get_osd_size()
+    if w <= 0 or h <= 0 then
+        return 0, 0
+    end
+    return osc_param.playresx / w, osc_param.playresy / h
+end
+
+-- return mouse position in virtual ASS coordinates (playresx/y)
+function get_virt_mouse_pos()
+    local sx, sy = get_virt_scale_factor()
+    local x, y = mp.get_mouse_pos()
+    return x * sx, y * sy
+end
+
+function set_virt_mouse_area(x0, y0, x1, y1, name)
+    local sx, sy = get_virt_scale_factor()
+    mp.set_mouse_area(x0 * sx, y0 * sy, x1 * sx, y1 * sy)
+end
+
 function scale_value(x0, x1, y0, y1, val)
     local m = (y1 - y0) / (x1 - x0)
     local b = y0 - (m * x0)
@@ -141,7 +162,7 @@ function mouse_hit(element)
 end
 
 function mouse_hit_coords(bX1, bY1, bX2, bY2)
-    local mX, mY = mp.get_mouse_pos()
+    local mX, mY = get_virt_mouse_pos()
     return (mX >= bX1 and mX <= bX2 and mY >= bY1 and mY <= bY2)
 end
 
@@ -182,7 +203,7 @@ end
 
 -- get value at current mouse position
 function get_slider_value(element)
-    return get_slider_value_at(element, mp.get_mouse_pos())
+    return get_slider_value_at(element, get_virt_mouse_pos())
 end
 
 function countone(val)
@@ -589,7 +610,7 @@ function render_elements(master_ass)
                     end
 
                     elem_ass:new_event()
-                    elem_ass:pos(mp.get_mouse_pos(), ty)
+                    elem_ass:pos(get_virt_mouse_pos(), ty)
                     elem_ass:an(an)
                     elem_ass:append(slider_lo.tooltip_style)
                     elem_ass:append(tooltiplabel)
@@ -1298,7 +1319,7 @@ function osc_init()
 
     -- set canvas resolution according to display aspect and scaling setting
     local baseResY = 720
-    local display_w, display_h, display_aspect = mp.get_screen_size()
+    local display_w, display_h, display_aspect = mp.get_osd_size()
     local scale = 1
 
     if (mp.get_property("video") == "no") then -- dummy/forced window
@@ -1718,8 +1739,8 @@ end
 
 function render()
     msg.debug("rendering")
-    local current_screen_sizeX, current_screen_sizeY, aspect = mp.get_screen_size()
-    local mouseX, mouseY = mp.get_mouse_pos()
+    local current_screen_sizeX, current_screen_sizeY, aspect = mp.get_osd_size()
+    local mouseX, mouseY = get_virt_mouse_pos()
     local now = mp.get_time()
 
     -- check if display changed, if so request reinit
@@ -1782,7 +1803,7 @@ function render()
 
     --mouse show/hide area
     for k,cords in pairs(osc_param.areas["showhide"]) do
-        mp.set_mouse_area(cords.x1, cords.y1, cords.x2, cords.y2, "showhide")
+        set_virt_mouse_area(cords.x1, cords.y1, cords.x2, cords.y2, "showhide")
     end
     do_enable_keybindings()
 
@@ -1791,7 +1812,7 @@ function render()
 
     for _,cords in ipairs(osc_param.areas["input"]) do
         if state.osc_visible then -- activate only when OSC is actually visible
-            mp.set_mouse_area(cords.x1, cords.y1, cords.x2, cords.y2, "input")
+            set_virt_mouse_area(cords.x1, cords.y1, cords.x2, cords.y2, "input")
         end
         if state.osc_visible ~= state.input_enabled then
             if state.osc_visible then
@@ -1887,7 +1908,7 @@ function process_event(source, what)
         state.mouse_down_counter = 0
 
     elseif source == "mouse_move" then
-        local mouseX, mouseY = mp.get_mouse_pos()
+        local mouseX, mouseY = get_virt_mouse_pos()
         if (user_opts.minmousemove == 0) or
             (not ((state.last_mouseX == nil) or (state.last_mouseY == nil)) and
                 ((math.abs(mouseX - state.last_mouseX) >= user_opts.minmousemove)
diff --git a/sub/osd.c b/sub/osd.c
index 81cfb7daa6..a9bc035c73 100644
--- a/sub/osd.c
+++ b/sub/osd.c
@@ -422,21 +422,6 @@ bool osd_query_and_reset_want_redraw(struct osd_state *osd)
     return r;
 }
 
-// Scale factor to translate OSD coordinates to what the obj uses internally.
-// osd_coordinates * (sw, sh) = obj_coordinates
-void osd_object_get_scale_factor(struct osd_state *osd, int obj,
-                                 double *sw, double *sh)
-{
-    int nw, nh;
-    osd_object_get_resolution(osd, obj, &nw, &nh);
-    pthread_mutex_lock(&osd->lock);
-    int vow = osd->objs[obj]->vo_res.w;
-    int voh = osd->objs[obj]->vo_res.h;
-    pthread_mutex_unlock(&osd->lock);
-    *sw = vow ? nw / (double)vow : 0;
-    *sh = voh ? nh / (double)voh : 0;
-}
-
 struct mp_osd_res osd_get_vo_res(struct osd_state *osd, int obj)
 {
     pthread_mutex_lock(&osd->lock);
diff --git a/sub/osd.h b/sub/osd.h
index 4e18ce7f7c..c066b09645 100644
--- a/sub/osd.h
+++ b/sub/osd.h
@@ -190,9 +190,6 @@ void osd_draw_on_image_p(struct osd_state *osd, struct mp_osd_res res,
 struct mp_image_params;
 struct mp_osd_res osd_res_from_image_params(const struct mp_image_params *p);
 
-void osd_object_get_scale_factor(struct osd_state *osd, int obj,
-                                 double *sw, double *sh);
-
 struct mp_osd_res osd_get_vo_res(struct osd_state *osd, int obj);
 
 void osd_rescale_bitmaps(struct sub_bitmaps *imgs, int frame_w, int frame_h,
@@ -211,8 +208,4 @@ void osd_get_function_sym(char *buffer, size_t buffer_size, int osd_function);
 extern const char *const osd_ass_0;
 extern const char *const osd_ass_1;
 
-// defined in backend, but locks if required
-void osd_object_get_resolution(struct osd_state *osd, int obj,
-                               int *out_w, int *out_h);
-
 #endif /* MPLAYER_SUB_H */
diff --git a/sub/osd_dummy.c b/sub/osd_dummy.c
index 5c50569dd6..1982870248 100644
--- a/sub/osd_dummy.c
+++ b/sub/osd_dummy.c
@@ -26,10 +26,3 @@ void osd_object_get_bitmaps(struct osd_state *osd, struct osd_object *obj,
 {
     *out_imgs = (struct sub_bitmaps) {0};
 }
-
-void osd_object_get_resolution(struct osd_state *osd, int obj,
-                               int *out_w, int *out_h)
-{
-    *out_w = 0;
-    *out_h = 0;
-}
diff --git a/sub/osd_libass.c b/sub/osd_libass.c
index eed2822380..cd28396746 100644
--- a/sub/osd_libass.c
+++ b/sub/osd_libass.c
@@ -477,13 +477,3 @@ void osd_object_get_bitmaps(struct osd_state *osd, struct osd_object *obj,
                         &obj->parts_cache, out_imgs);
     talloc_steal(obj, obj->parts_cache);
 }
-
-void osd_object_get_resolution(struct osd_state *osd, int obj,
-                               int *out_w, int *out_h)
-{
-    pthread_mutex_lock(&osd->lock);
-    struct osd_object *osd_obj = osd->objs[obj];
-    *out_w = osd_obj->osd_track ? osd_obj->osd_track->PlayResX : 0;
-    *out_h = osd_obj->osd_track ? osd_obj->osd_track->PlayResY : 0;
-    pthread_mutex_unlock(&osd->lock);
-}