diff --git a/video/out/vo.c b/video/out/vo.c
index 474d4e0c52..2db6afa05a 100644
--- a/video/out/vo.c
+++ b/video/out/vo.c
@@ -157,9 +157,10 @@ static struct vo *vo_create(struct mp_vo_opts *opts,
     if (vo->driver->encode != !!vo->encode_lavc_ctx)
         goto error;
     struct m_config *config = m_config_from_obj_desc(vo, &desc);
-    if (m_config_initialize_obj(config, &desc, &vo->priv, &args) < 0)
+    if (m_config_set_obj_params(config, args) < 0)
         goto error;
-    if (vo->driver->preinit(vo, (char *)args))
+    vo->priv = config->optstruct;
+    if (vo->driver->preinit(vo))
         goto error;
     return vo;
 error:
diff --git a/video/out/vo.h b/video/out/vo.h
index 80c51dfc08..ae84f9d0c9 100644
--- a/video/out/vo.h
+++ b/video/out/vo.h
@@ -151,11 +151,9 @@ struct vo_driver {
 
     const vo_info_t *info;
     /*
-     * Preinitializes driver (real INITIALIZATION)
-     *   arg - currently it's vo_subdevice
      *   returns: zero on successful initialization, non-zero on error.
      */
-    int (*preinit)(struct vo *vo, const char *arg);
+    int (*preinit)(struct vo *vo);
 
     /*
      * Whether the given image format is supported and config() will succeed.
diff --git a/video/out/vo_caca.c b/video/out/vo_caca.c
index dd6d76f311..a14441e4f4 100644
--- a/video/out/vo_caca.c
+++ b/video/out/vo_caca.c
@@ -246,13 +246,8 @@ static void uninit(struct vo *vo)
     caca_free_canvas(canvas);
 }
 
-static int preinit(struct vo *vo, const char *arg)
+static int preinit(struct vo *vo)
 {
-    if (arg) {
-        mp_msg(MSGT_VO, MSGL_ERR, "vo_caca: Unknown subdevice: %s\n", arg);
-        return ENOSYS;
-    }
-
     canvas = caca_create_canvas(0, 0);
     if (canvas == NULL) {
         mp_msg(MSGT_VO, MSGL_ERR, "vo_caca: failed to create canvas\n");
diff --git a/video/out/vo_corevideo.m b/video/out/vo_corevideo.m
index 3a45c42921..cb60fef95d 100644
--- a/video/out/vo_corevideo.m
+++ b/video/out/vo_corevideo.m
@@ -263,7 +263,7 @@ static void uninit(struct vo *vo)
 }
 
 
-static int preinit(struct vo *vo, const char *arg)
+static int preinit(struct vo *vo)
 {
     struct priv *p = vo->priv;
 
diff --git a/video/out/vo_direct3d.c b/video/out/vo_direct3d.c
index 9c5a306363..cc8b4d67f8 100644
--- a/video/out/vo_direct3d.c
+++ b/video/out/vo_direct3d.c
@@ -1157,7 +1157,7 @@ static void update_colorspace(d3d_priv *priv)
  *  @return 0 on success, -1 on failure
  */
 
-static int preinit(struct vo *vo, const char *arg)
+static int preinit(struct vo *vo)
 {
     d3d_priv *priv = vo->priv;
     priv->vo = vo;
diff --git a/video/out/vo_image.c b/video/out/vo_image.c
index af9b0edd4c..03869146f7 100644
--- a/video/out/vo_image.c
+++ b/video/out/vo_image.c
@@ -152,7 +152,7 @@ static void uninit(struct vo *vo)
     mp_image_unrefp(&p->current);
 }
 
-static int preinit(struct vo *vo, const char *arg)
+static int preinit(struct vo *vo)
 {
     vo->untimed = true;
     return 0;
diff --git a/video/out/vo_lavc.c b/video/out/vo_lavc.c
index 6c28169baa..7ee372f053 100644
--- a/video/out/vo_lavc.c
+++ b/video/out/vo_lavc.c
@@ -60,7 +60,7 @@ struct priv {
     struct mp_csp_details colorspace;
 };
 
-static int preinit(struct vo *vo, const char *arg)
+static int preinit(struct vo *vo)
 {
     struct priv *vc;
     if (!encode_lavc_available(vo->encode_lavc_ctx)) {
diff --git a/video/out/vo_null.c b/video/out/vo_null.c
index 685b9c3a84..88c355033f 100644
--- a/video/out/vo_null.c
+++ b/video/out/vo_null.c
@@ -56,12 +56,8 @@ static void uninit(struct vo *vo)
 {
 }
 
-static int preinit(struct vo *vo, const char *arg)
+static int preinit(struct vo *vo)
 {
-    if (arg) {
-        mp_tmsg(MSGT_VO, MSGL_WARN, "[VO_NULL] Unknown subdevice: %s.\n", arg);
-        return ENOSYS;
-    }
     return 0;
 }
 
diff --git a/video/out/vo_opengl.c b/video/out/vo_opengl.c
index 6e523a6b8c..f460ea95f0 100644
--- a/video/out/vo_opengl.c
+++ b/video/out/vo_opengl.c
@@ -303,7 +303,7 @@ static void uninit(struct vo *vo)
     }
 }
 
-static int preinit(struct vo *vo, const char *arg)
+static int preinit(struct vo *vo)
 {
     struct gl_priv *p = vo->priv;
     p->vo = vo;
diff --git a/video/out/vo_opengl_old.c b/video/out/vo_opengl_old.c
index 59f63205e8..2caf0c3f28 100644
--- a/video/out/vo_opengl_old.c
+++ b/video/out/vo_opengl_old.c
@@ -2077,7 +2077,7 @@ static void uninit(struct vo *vo)
     p->gl = NULL;
 }
 
-static int preinit(struct vo *vo, const char *arg)
+static int preinit(struct vo *vo)
 {
     struct gl_priv *p = vo->priv;
 
diff --git a/video/out/vo_sdl.c b/video/out/vo_sdl.c
index 35d3ab4962..c5ecc2be8c 100644
--- a/video/out/vo_sdl.c
+++ b/video/out/vo_sdl.c
@@ -728,7 +728,7 @@ static void draw_osd(struct vo *vo, struct osd_state *osd)
     osd_draw(osd, vc->osd_res, osd->vo_pts, 0, formats, draw_osd_cb, vo);
 }
 
-static int preinit(struct vo *vo, const char *arg)
+static int preinit(struct vo *vo)
 {
     struct priv *vc = vo->priv;
 
diff --git a/video/out/vo_vdpau.c b/video/out/vo_vdpau.c
index 6319945ddb..85ad4ecf80 100644
--- a/video/out/vo_vdpau.c
+++ b/video/out/vo_vdpau.c
@@ -1439,7 +1439,7 @@ static void uninit(struct vo *vo)
         av_freep(&vc->surface_render[i].bitstream_buffers);
 }
 
-static int preinit(struct vo *vo, const char *arg)
+static int preinit(struct vo *vo)
 {
     struct vdpctx *vc = vo->priv;
 
diff --git a/video/out/vo_x11.c b/video/out/vo_x11.c
index 0762d55400..6eef918b9e 100644
--- a/video/out/vo_x11.c
+++ b/video/out/vo_x11.c
@@ -602,7 +602,7 @@ static void uninit(struct vo *vo)
     vo_x11_uninit(vo);
 }
 
-static int preinit(struct vo *vo, const char *arg)
+static int preinit(struct vo *vo)
 {
     struct priv *p = vo->priv;
     p->vo = vo;
diff --git a/video/out/vo_xv.c b/video/out/vo_xv.c
index 6c91e7bcd4..b7e3687ef7 100644
--- a/video/out/vo_xv.c
+++ b/video/out/vo_xv.c
@@ -722,7 +722,7 @@ static void uninit(struct vo *vo)
     vo_x11_uninit(vo);
 }
 
-static int preinit(struct vo *vo, const char *arg)
+static int preinit(struct vo *vo)
 {
     XvPortID xv_p;
     int busy_ports = 0;