video: add an option to tune waiting for video timing

Probably mostly useful for the libmpv render API.

options/options.c

@@ -139,6 +139,7 @@ static const m_option_t mp_vo_opt_list[] = {
     OPT_FLAG("keepaspect-window", keepaspect_window, 0),
     OPT_FLAG("hidpi-window-scale", hidpi_window_scale, 0),
     OPT_FLAG("native-fs", native_fs, 0),
+    OPT_DOUBLERANGE("video-timing-offset", timing_offset, 0, 0.0, 1.0),
 #if HAVE_X11
     OPT_CHOICE("x11-netwm", x11_netwm, 0,
                ({"auto", 0}, {"no", -1}, {"yes", 1})),
@@ -176,6 +177,7 @@ const struct m_sub_options vo_sub_opts = {
         .x11_bypass_compositor = 2,
         .mmcss_profile = "Playback",
         .ontop_level = -1,
+        .timing_offset = 0.050,
     },
 };