player/command: add deinterlace-active property

DOCS/man/input.rst

@@ -2174,6 +2174,11 @@ Property list
 ``af-metadata/<filter-label>``
     Equivalent to ``vf-metadata/<filter-label>``, but for audio filters.
 
+``deinterlace-active``
+    Returns ``yes``/true if mpv's deinterlacing filter is active. Note that it
+    will not detect any manually inserted deinterlacing filters done via
+    ``--vf``.
+
 ``idle-active``
     Returns ``yes``/true if no file is loaded, but the player is staying around
     because of the ``--idle`` option.

filters/f_auto_filters.c

@@ -168,6 +168,12 @@ static const struct mp_filter_info deint_filter = {
     .destroy = deint_destroy,
 };
 
+bool mp_deint_active(struct mp_filter *f)
+{
+    struct deint_priv *p = f->priv;
+    return p->deinterlace_active;
+}
+
 struct mp_filter *mp_deint_create(struct mp_filter *parent)
 {
     struct mp_filter *f = mp_filter_create(parent, &deint_filter);

filters/f_auto_filters.h

@@ -11,3 +11,5 @@ struct mp_filter *mp_autorotate_create(struct mp_filter *parent);
 
 // Insert a filter that inserts scaletempo2 depending on speed settings.
 struct mp_filter *mp_autoaspeed_create(struct mp_filter *parent);
+
+bool mp_deint_active(struct mp_filter *parent);

filters/f_output_chain.c

@@ -518,6 +518,17 @@ double mp_output_get_measured_total_delay(struct mp_output_chain *c)
     return delay;
 }
 
+bool mp_output_chain_deinterlace_active(struct mp_output_chain *c)
+{
+    struct chain *p = c->f->priv;
+    for (int n = 0; n < p->num_all_filters; n++) {
+        struct mp_user_filter *u = p->all_filters[n];
+        if (strcmp(u->name, "userdeint") == 0)
+            return mp_deint_active(u->f);
+    }
+    return false;
+}
+
 bool mp_output_chain_update_filters(struct mp_output_chain *c,
                                     struct m_obj_settings *list)
 {

filters/f_output_chain.h

@@ -85,3 +85,6 @@ void mp_output_chain_set_audio_speed(struct mp_output_chain *p,
 // due to the change.
 // Makes sense for audio only.
 double mp_output_get_measured_total_delay(struct mp_output_chain *p);
+
+// Check if deinterlace user filter is inserted
+bool mp_output_chain_deinterlace_active(struct mp_output_chain *p);

player/command.c

@@ -1357,6 +1357,18 @@ static int mp_property_core_idle(void *ctx, struct m_property *prop,
     return m_property_bool_ro(action, arg, !mpctx->playback_active);
 }
 
+static int mp_property_deinterlace(void *ctx, struct m_property *prop,
+                                   int action, void *arg)
+{
+    MPContext *mpctx = ctx;
+    struct vo_chain *vo_c = mpctx->vo_chain;
+    if (!vo_c)
+        return M_PROPERTY_UNAVAILABLE;
+
+    bool deinterlace_active = mp_output_chain_deinterlace_active(vo_c->filter);
+    return m_property_bool_ro(action, arg, deinterlace_active);
+}
+
 static int mp_property_idle(void *ctx, struct m_property *prop,
                             int action, void *arg)
 {
@@ -3882,6 +3894,7 @@ static const struct m_property mp_properties_base[] = {
     {"clock", mp_property_clock},
     {"seekable", mp_property_seekable},
     {"partially-seekable", mp_property_partially_seekable},
+    {"deinterlace-active", mp_property_deinterlace},
     {"idle-active", mp_property_idle},
     {"window-id", mp_property_window_id},
 
@@ -4056,7 +4069,8 @@ static const char *const *const mp_event_property_change[] = {
       "secondary-sub-text", "audio-bitrate", "video-bitrate", "sub-bitrate",
       "decoder-frame-drop-count", "frame-drop-count", "video-frame-info",
       "vf-metadata", "af-metadata", "sub-start", "sub-end", "secondary-sub-start",
-      "secondary-sub-end", "video-out-params", "video-dec-params", "video-params"),
+      "secondary-sub-end", "video-out-params", "video-dec-params", "video-params",
+      "deinterlace-active"),
     E(MP_EVENT_DURATION_UPDATE, "duration"),
     E(MPV_EVENT_VIDEO_RECONFIG, "video-out-params", "video-params",
       "video-format", "video-codec", "video-bitrate", "dwidth", "dheight",