command: make property "deinterlace" unavailable if deinterlacer absent

The "deinterlace" property was stuck at "no" if there wasn't actually
any switchable deinterlacer (like yadif or vdpau) in the video chain.

Also, take care of returning only 0/1 values. It appears yadif and vdpau
return their current deinterlacer mode, which is not always the value 0
or 1.

1 files changed, 5 insertions, 3 deletions

diff --git a/command.c b/command.c
index 189b086b94..5b615ef5be 100644
--- a/command.c
+++ b/command.c
@@ -854,13 +854,15 @@ static int mp_property_fullscreen(m_option_t *prop, int action, void *arg,
 static int mp_property_deinterlace(m_option_t *prop, int action,
                                    void *arg, MPContext *mpctx)
 {
-    vf_instance_t *vf;
     if (!mpctx->sh_video || !mpctx->sh_video->vfilter)
         return M_PROPERTY_UNAVAILABLE;
-    vf = mpctx->sh_video->vfilter;
+    vf_instance_t *vf = mpctx->sh_video->vfilter;
+    int enabled = 0;
+    if (vf->control(vf, VFCTRL_GET_DEINTERLACE, &enabled) != CONTROL_OK)
+        return M_PROPERTY_UNAVAILABLE;
     switch (action) {
     case M_PROPERTY_GET:
-        vf->control(vf, VFCTRL_GET_DEINTERLACE, arg);
+        *(int *)arg = !!enabled;
         return M_PROPERTY_OK;
     case M_PROPERTY_SET:
         vf->control(vf, VFCTRL_SET_DEINTERLACE, arg);