dvdspu: negotiate overlay composition meta with downstream

This allows attaching the overlay composition as a meta on the video
buffer instead of blending with the video.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5827>

subprojects/gst-plugins-bad/gst/dvdspu/gstdvdspu.c

@@ -58,17 +58,23 @@ enum
 
 #define VIDEO_FORMATS GST_VIDEO_OVERLAY_COMPOSITION_BLEND_FORMATS
 
+#define DVDSPU_CAPS GST_VIDEO_CAPS_MAKE (VIDEO_FORMATS)
+#define DVDSPU_ALL_CAPS DVDSPU_CAPS ";" \
+    GST_VIDEO_CAPS_MAKE_WITH_FEATURES ("ANY", GST_VIDEO_FORMATS_ALL)
+
+static GstStaticCaps sw_template_caps = GST_STATIC_CAPS (DVDSPU_CAPS);
+
 static GstStaticPadTemplate video_sink_factory =
 GST_STATIC_PAD_TEMPLATE ("video",
     GST_PAD_SINK,
     GST_PAD_ALWAYS,
-    GST_STATIC_CAPS (GST_VIDEO_CAPS_MAKE (VIDEO_FORMATS))
+    GST_STATIC_CAPS (DVDSPU_ALL_CAPS)
     );
 
 static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
     GST_PAD_SRC,
     GST_PAD_ALWAYS,
-    GST_STATIC_CAPS (GST_VIDEO_CAPS_MAKE (VIDEO_FORMATS))
+    GST_STATIC_CAPS (DVDSPU_ALL_CAPS)
     );
 
 static GstStaticPadTemplate subpic_sink_factory =
@@ -93,8 +99,10 @@ static gboolean gst_dvd_spu_src_event (GstPad * pad, GstObject * parent,
     GstEvent * event);
 static gboolean gst_dvd_spu_src_query (GstPad * pad, GstObject * parent,
     GstQuery * query);
+static GstCaps *gst_dvd_spu_src_get_caps (GstDVDSpu * dvdspu, GstPad * pad,
+    GstCaps * filter);
 
-static GstCaps *gst_dvd_spu_video_proxy_getcaps (GstPad * pad,
+static GstCaps *gst_dvd_spu_video_get_caps (GstDVDSpu * dvdspu, GstPad * pad,
     GstCaps * filter);
 static gboolean gst_dvd_spu_video_set_caps (GstDVDSpu * dvdspu, GstPad * pad,
     GstCaps * caps);
@@ -113,6 +121,7 @@ static gboolean gst_dvd_spu_subpic_event (GstPad * pad, GstObject * parent,
     GstEvent * event);
 static gboolean gst_dvd_spu_subpic_set_caps (GstDVDSpu * dvdspu, GstPad * pad,
     GstCaps * caps);
+static gboolean gst_dvd_spu_negotiate (GstDVDSpu * dvdspu, GstCaps * caps);
 
 static void gst_dvd_spu_clear (GstDVDSpu * dvdspu);
 static void gst_dvd_spu_flush_spu_info (GstDVDSpu * dvdspu,
@@ -292,6 +301,7 @@ gst_dvd_spu_src_event (GstPad * pad, GstObject * parent, GstEvent * event)
 static gboolean
 gst_dvd_spu_src_query (GstPad * pad, GstObject * parent, GstQuery * query)
 {
+  GstDVDSpu *dvdspu = GST_DVD_SPU (parent);
   gboolean res = FALSE;
 
   switch (GST_QUERY_TYPE (query)) {
@@ -300,7 +310,7 @@ gst_dvd_spu_src_query (GstPad * pad, GstObject * parent, GstQuery * query)
       GstCaps *filter, *caps;
 
       gst_query_parse_caps (query, &filter);
-      caps = gst_dvd_spu_video_proxy_getcaps (pad, filter);
+      caps = gst_dvd_spu_src_get_caps (dvdspu, pad, filter);
       gst_query_set_caps_result (query, caps);
       gst_caps_unref (caps);
       res = TRUE;
@@ -314,51 +324,239 @@ gst_dvd_spu_src_query (GstPad * pad, GstObject * parent, GstQuery * query)
   return res;
 }
 
+static gboolean
+gst_dvd_spu_can_handle_caps (GstCaps * caps)
+{
+  GstCaps *sw_caps;
+  gboolean ret;
+
+  sw_caps = gst_static_caps_get (&sw_template_caps);
+  ret = gst_caps_is_subset (caps, sw_caps);
+  gst_caps_unref (sw_caps);
+
+  return ret;
+}
+
 static gboolean
 gst_dvd_spu_video_set_caps (GstDVDSpu * dvdspu, GstPad * pad, GstCaps * caps)
 {
-  gboolean res = FALSE;
   GstVideoInfo info;
-  SpuState *state;
+  gboolean ret = FALSE;
 
   if (!gst_video_info_from_caps (&info, caps))
-    goto done;
+    goto invalid_caps;
+
+  dvdspu->spu_state.info = info;
+
+  ret = gst_dvd_spu_negotiate (dvdspu, caps);
 
   DVD_SPU_LOCK (dvdspu);
-  state = &dvdspu->spu_state;
+  if (!dvdspu->attach_compo_to_buffer && !gst_dvd_spu_can_handle_caps (caps)) {
-  state->info = info;
+    GST_DEBUG_OBJECT (dvdspu, "unsupported caps %" GST_PTR_FORMAT, caps);
+    ret = FALSE;
+  }
+
   DVD_SPU_UNLOCK (dvdspu);
 
-  res = TRUE;
+  return ret;
-done:
+
-  return res;
+  /* ERRORS */
+invalid_caps:
+  {
+    GST_DEBUG_OBJECT (dvdspu, "could not parse caps");
+    return FALSE;
+  }
+}
+
+
+/**
+ * gst_dvd_spu_add_feature_and_intersect:
+ *
+ * Creates a new #GstCaps containing the (given caps +
+ * given caps feature) + (given caps intersected by the
+ * given filter).
+ *
+ * Returns: the new #GstCaps
+ */
+static GstCaps *
+gst_dvd_spu_add_feature_and_intersect (GstCaps * caps,
+    const gchar * feature, GstCaps * filter)
+{
+  int i, caps_size;
+  GstCaps *new_caps;
+
+  new_caps = gst_caps_copy (caps);
+
+  caps_size = gst_caps_get_size (new_caps);
+  for (i = 0; i < caps_size; i++) {
+    GstCapsFeatures *features = gst_caps_get_features (new_caps, i);
+    if (!gst_caps_features_is_any (features)) {
+      gst_caps_features_add (features, feature);
+    }
+  }
+
+  gst_caps_append (new_caps, gst_caps_intersect_full (caps,
+          filter, GST_CAPS_INTERSECT_FIRST));
+
+  return new_caps;
+}
+
+/**
+ * gst_dvd_spu_intersect_by_feature:
+ *
+ * Creates a new #GstCaps based on the following filtering rule.
+ *
+ * For each individual caps contained in given caps, if the
+ * caps uses the given caps feature, keep a version of the caps
+ * with the feature and an another one without. Otherwise, intersect
+ * the caps with the given filter.
+ *
+ * Returns: the new #GstCaps
+ */
+static GstCaps *
+gst_dvd_spu_intersect_by_feature (GstCaps * caps,
+    const gchar * feature, GstCaps * filter)
+{
+  int i, caps_size;
+  GstCaps *new_caps;
+
+  new_caps = gst_caps_new_empty ();
+
+  caps_size = gst_caps_get_size (caps);
+  for (i = 0; i < caps_size; i++) {
+    GstStructure *caps_structure = gst_caps_get_structure (caps, i);
+    GstCapsFeatures *caps_features =
+        gst_caps_features_copy (gst_caps_get_features (caps, i));
+    GstCaps *filtered_caps;
+    GstCaps *simple_caps =
+        gst_caps_new_full (gst_structure_copy (caps_structure), NULL);
+    gst_caps_set_features (simple_caps, 0, caps_features);
+
+    if (gst_caps_features_contains (caps_features, feature)) {
+      gst_caps_append (new_caps, gst_caps_copy (simple_caps));
+
+      gst_caps_features_remove (caps_features, feature);
+      filtered_caps = gst_caps_ref (simple_caps);
+    } else {
+      filtered_caps = gst_caps_intersect_full (simple_caps, filter,
+          GST_CAPS_INTERSECT_FIRST);
+    }
+
+    gst_caps_unref (simple_caps);
+    gst_caps_append (new_caps, filtered_caps);
+  }
+
+  return new_caps;
 }
 
 static GstCaps *
-gst_dvd_spu_video_proxy_getcaps (GstPad * pad, GstCaps * filter)
+gst_dvd_spu_video_get_caps (GstDVDSpu * dvdspu, GstPad * pad, GstCaps * filter)
 {
-  GstDVDSpu *dvdspu = GST_DVD_SPU (gst_pad_get_parent (pad));
+  GstPad *srcpad = dvdspu->srcpad;
-  GstCaps *caps;
+  GstCaps *peer_caps = NULL, *caps = NULL, *dvdspu_filter = NULL;
-  GstPad *otherpad;
 
-  /* Proxy the getcaps between videosink and the srcpad, ignoring the 
+  if (filter) {
-   * subpicture sink pad */
+    /* filter caps + composition feature + filter caps
-  otherpad = (pad == dvdspu->srcpad) ? dvdspu->videosinkpad : dvdspu->srcpad;
+     * filtered by the software caps. */
+    GstCaps *sw_caps = gst_static_caps_get (&sw_template_caps);
+    dvdspu_filter = gst_dvd_spu_add_feature_and_intersect (filter,
+        GST_CAPS_FEATURE_META_GST_VIDEO_OVERLAY_COMPOSITION, sw_caps);
+    gst_caps_unref (sw_caps);
 
-  caps = gst_pad_peer_query_caps (otherpad, filter);
+    GST_DEBUG_OBJECT (dvdspu, "dvdspu filter %" GST_PTR_FORMAT, dvdspu_filter);
-  if (caps) {
+  }
-    GstCaps *temp, *templ;
+
+  peer_caps = gst_pad_peer_query_caps (srcpad, dvdspu_filter);
+
+  if (dvdspu_filter)
+    gst_caps_unref (dvdspu_filter);
+
+  if (peer_caps) {
+    GST_DEBUG_OBJECT (pad, "peer caps %" GST_PTR_FORMAT, peer_caps);
+
+    if (gst_caps_is_any (peer_caps)) {
+      /* if peer returns ANY caps, return filtered src pad template caps */
+      caps = gst_caps_copy (gst_pad_get_pad_template_caps (srcpad));
+    } else {
+      /* duplicate caps which contains the composition into one version with
+       * the meta and one without. Filter the other caps by the software caps */
+      GstCaps *sw_caps = gst_static_caps_get (&sw_template_caps);
+      caps = gst_dvd_spu_intersect_by_feature (peer_caps,
+          GST_CAPS_FEATURE_META_GST_VIDEO_OVERLAY_COMPOSITION, sw_caps);
+      gst_caps_unref (sw_caps);
+    }
+
+    gst_caps_unref (peer_caps);
 
-    templ = gst_pad_get_pad_template_caps (otherpad);
-    temp = gst_caps_intersect (caps, templ);
-    gst_caps_unref (templ);
-    gst_caps_unref (caps);
-    caps = temp;
   } else {
+    /* no peer, our padtemplate is enough then */
     caps = gst_pad_get_pad_template_caps (pad);
   }
 
-  gst_object_unref (dvdspu);
+  if (filter) {
+    GstCaps *intersection = gst_caps_intersect_full (filter, caps,
+        GST_CAPS_INTERSECT_FIRST);
+    gst_caps_unref (caps);
+    caps = intersection;
+  }
+
+  GST_DEBUG_OBJECT (dvdspu, "returning %" GST_PTR_FORMAT, caps);
+
+  return caps;
+}
+
+static GstCaps *
+gst_dvd_spu_src_get_caps (GstDVDSpu * dvdspu, GstPad * pad, GstCaps * filter)
+{
+  GstPad *sinkpad = dvdspu->videosinkpad;
+  GstCaps *peer_caps = NULL, *caps = NULL, *dvdspu_filter = NULL;
+
+  if (filter) {
+    /* duplicate filter caps which contains the composition into one version
+     * with the meta and one without. Filter the other caps by the software
+     * caps */
+    GstCaps *sw_caps = gst_static_caps_get (&sw_template_caps);
+    dvdspu_filter = gst_dvd_spu_intersect_by_feature (filter,
+        GST_CAPS_FEATURE_META_GST_VIDEO_OVERLAY_COMPOSITION, sw_caps);
+    gst_caps_unref (sw_caps);
+  }
+
+  peer_caps = gst_pad_peer_query_caps (sinkpad, dvdspu_filter);
+
+  if (dvdspu_filter)
+    gst_caps_unref (dvdspu_filter);
+
+  if (peer_caps) {
+    GST_DEBUG_OBJECT (pad, "peer caps %" GST_PTR_FORMAT, peer_caps);
+
+    if (gst_caps_is_any (peer_caps)) {
+      /* if peer returns ANY caps, return filtered sink pad template caps */
+      caps = gst_caps_copy (gst_pad_get_pad_template_caps (sinkpad));
+    } else {
+      /* return upstream caps + composition feature + upstream caps
+       * filtered by the software caps. */
+      GstCaps *sw_caps = gst_static_caps_get (&sw_template_caps);
+      caps = gst_dvd_spu_add_feature_and_intersect (peer_caps,
+          GST_CAPS_FEATURE_META_GST_VIDEO_OVERLAY_COMPOSITION, sw_caps);
+      gst_caps_unref (sw_caps);
+    }
+
+    gst_caps_unref (peer_caps);
+
+  } else {
+    /* no peer, our padtemplate is enough then */
+    caps = gst_pad_get_pad_template_caps (pad);
+  }
+
+  if (filter) {
+    GstCaps *intersection = gst_caps_intersect_full (filter, caps,
+        GST_CAPS_INTERSECT_FIRST);
+    gst_caps_unref (caps);
+    caps = intersection;
+  }
+
+  GST_DEBUG_OBJECT (dvdspu, "returning %" GST_PTR_FORMAT, caps);
+
   return caps;
 }
 
@@ -487,12 +685,16 @@ gst_dvd_spu_video_event (GstPad * pad, GstObject * parent, GstEvent * event)
       break;
     }
     case GST_EVENT_FLUSH_START:
+      DVD_SPU_LOCK (dvdspu);
+      dvdspu->video_flushing = TRUE;
+      DVD_SPU_UNLOCK (dvdspu);
       res = gst_pad_event_default (pad, parent, event);
       goto done;
     case GST_EVENT_FLUSH_STOP:
       res = gst_pad_event_default (pad, parent, event);
 
       DVD_SPU_LOCK (dvdspu);
+      dvdspu->video_flushing = FALSE;
       gst_segment_init (&dvdspu->video_seg, GST_FORMAT_UNDEFINED);
       gst_buffer_replace (&dvdspu->ref_frame, NULL);
       gst_buffer_replace (&dvdspu->pending_frame, NULL);
@@ -516,6 +718,7 @@ error:
 static gboolean
 gst_dvd_spu_video_query (GstPad * pad, GstObject * parent, GstQuery * query)
 {
+  GstDVDSpu *dvdspu = GST_DVD_SPU (parent);
   gboolean res = FALSE;
 
   switch (GST_QUERY_TYPE (query)) {
@@ -524,7 +727,7 @@ gst_dvd_spu_video_query (GstPad * pad, GstObject * parent, GstQuery * query)
       GstCaps *filter, *caps;
 
       gst_query_parse_caps (query, &filter);
-      caps = gst_dvd_spu_video_proxy_getcaps (pad, filter);
+      caps = gst_dvd_spu_video_get_caps (dvdspu, pad, filter);
       gst_query_set_caps_result (query, caps);
       gst_caps_unref (caps);
       res = TRUE;
@@ -546,6 +749,9 @@ gst_dvd_spu_video_chain (GstPad * pad, GstObject * parent, GstBuffer * buf)
 
   g_return_val_if_fail (dvdspu != NULL, GST_FLOW_ERROR);
 
+  if (gst_pad_check_reconfigure (dvdspu->srcpad))
+    gst_dvd_spu_negotiate (dvdspu, NULL);
+
   GST_LOG_OBJECT (dvdspu, "video buffer %p with TS %" GST_TIME_FORMAT,
       buf, GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buf)));
 
@@ -827,6 +1033,11 @@ gstspu_render (GstDVDSpu * dvdspu, GstBuffer * buf)
   if (!composition)
     return;
 
+  if (dvdspu->attach_compo_to_buffer) {
+    gst_buffer_add_video_overlay_composition_meta (buf, composition);
+    goto done;
+  }
+
   if (!gst_video_frame_map (&frame, &dvdspu->spu_state.info, buf,
           GST_MAP_READWRITE)) {
     GST_WARNING_OBJECT (dvdspu, "failed to map video frame for blending");
@@ -1063,6 +1274,134 @@ submit_new_spu_packet (GstDVDSpu * dvdspu, GstBuffer * buf)
   }
 }
 
+static gboolean
+gst_dvd_spu_negotiate (GstDVDSpu * dvdspu, GstCaps * caps)
+{
+  gboolean upstream_has_meta = FALSE;
+  gboolean caps_has_meta = FALSE;
+  gboolean alloc_has_meta = FALSE;
+  gboolean attach = FALSE;
+  gboolean ret = TRUE;
+  GstCapsFeatures *f;
+  GstCaps *overlay_caps;
+  GstQuery *query;
+
+  GST_DEBUG_OBJECT (dvdspu, "performing negotiation");
+
+  /* Clear any pending reconfigure to avoid negotiating twice */
+  gst_pad_check_reconfigure (dvdspu->srcpad);
+
+  if (!caps)
+    caps = gst_pad_get_current_caps (dvdspu->videosinkpad);
+  else
+    gst_caps_ref (caps);
+
+  if (!caps || gst_caps_is_empty (caps))
+    goto no_format;
+
+  /* Check if upstream caps have meta */
+  if ((f = gst_caps_get_features (caps, 0))) {
+    upstream_has_meta = gst_caps_features_contains (f,
+        GST_CAPS_FEATURE_META_GST_VIDEO_OVERLAY_COMPOSITION);
+  }
+
+  if (upstream_has_meta) {
+    overlay_caps = gst_caps_ref (caps);
+  } else {
+    GstCaps *peercaps;
+
+    /* BaseTransform requires caps for the allocation query to work */
+    overlay_caps = gst_caps_copy (caps);
+    f = gst_caps_get_features (overlay_caps, 0);
+    gst_caps_features_add (f,
+        GST_CAPS_FEATURE_META_GST_VIDEO_OVERLAY_COMPOSITION);
+
+    /* Then check if downstream accept dvdspu composition in caps */
+    /* FIXME: We should probably check if downstream *prefers* the
+     * dvdspu meta, and only enforce usage of it if we can't handle
+     * the format ourselves and thus would have to drop the overlays.
+     * Otherwise we should prefer what downstream wants here.
+     */
+    peercaps = gst_pad_peer_query_caps (dvdspu->srcpad, NULL);
+    caps_has_meta = gst_caps_can_intersect (peercaps, overlay_caps);
+    gst_caps_unref (peercaps);
+
+    GST_DEBUG ("caps have dvdspu meta %d", caps_has_meta);
+  }
+
+  if (upstream_has_meta || caps_has_meta) {
+    /* Send caps immediatly, it's needed by GstBaseTransform to get a reply
+     * from allocation query */
+    ret = gst_pad_set_caps (dvdspu->srcpad, overlay_caps);
+
+    /* First check if the allocation meta has compositon */
+    query = gst_query_new_allocation (overlay_caps, FALSE);
+
+    if (!gst_pad_peer_query (dvdspu->srcpad, query)) {
+      /* no problem, we use the query defaults */
+      GST_DEBUG_OBJECT (dvdspu, "ALLOCATION query failed");
+
+      /* In case we were flushing, mark reconfigure and fail this method,
+       * will make it retry */
+      if (dvdspu->video_flushing)
+        ret = FALSE;
+    }
+
+    alloc_has_meta = gst_query_find_allocation_meta (query,
+        GST_VIDEO_OVERLAY_COMPOSITION_META_API_TYPE, NULL);
+
+    GST_DEBUG ("sink alloc has dvdspu meta %d", alloc_has_meta);
+
+    gst_query_unref (query);
+  }
+
+  /* For backward compatbility, we will prefer bliting if downstream
+   * allocation does not support the meta. In other case we will prefer
+   * attaching, and will fail the negotiation in the unlikely case we are
+   * force to blit, but format isn't supported. */
+
+  if (upstream_has_meta) {
+    attach = TRUE;
+  } else if (caps_has_meta) {
+    if (alloc_has_meta) {
+      attach = TRUE;
+    } else {
+      /* Don't attach unless we cannot handle the format */
+      attach = !gst_dvd_spu_can_handle_caps (caps);
+    }
+  } else {
+    ret = gst_dvd_spu_can_handle_caps (caps);
+  }
+
+  /* If we attach, then pick the dvdspu caps */
+  if (attach) {
+    GST_DEBUG_OBJECT (dvdspu, "Using caps %" GST_PTR_FORMAT, overlay_caps);
+    /* Caps where already sent */
+  } else if (ret) {
+    GST_DEBUG_OBJECT (dvdspu, "Using caps %" GST_PTR_FORMAT, caps);
+    ret = gst_pad_set_caps (dvdspu->srcpad, caps);
+  }
+
+  dvdspu->attach_compo_to_buffer = attach;
+
+  if (!ret) {
+    GST_DEBUG_OBJECT (dvdspu, "negotiation failed, schedule reconfigure");
+    gst_pad_mark_reconfigure (dvdspu->srcpad);
+  }
+
+  gst_caps_unref (overlay_caps);
+  gst_caps_unref (caps);
+
+  return ret;
+
+no_format:
+  {
+    if (caps)
+      gst_caps_unref (caps);
+    return FALSE;
+  }
+}
+
 static GstFlowReturn
 gst_dvd_spu_subpic_chain (GstPad * pad, GstObject * parent, GstBuffer * buf)
 {

subprojects/gst-plugins-bad/gst/dvdspu/gstdvdspu.h

@@ -94,6 +94,7 @@ struct _GstDVDSpu {
   /* Mutex to protect state we access from different chain funcs */
   GMutex spu_lock;
 
+  gboolean video_flushing;
   GstSegment video_seg;
   GstSegment subp_seg;
 
@@ -112,6 +113,9 @@ struct _GstDVDSpu {
 
   /* Buffer to push after handling a DVD event, if any */
   GstBuffer *pending_frame;
+
+  /* Overlay composition */
+  gboolean attach_compo_to_buffer;
 };
 
 struct _GstDVDSpuClass {