Merge pull request #4 from everycastlabs/add-feature-rank

Add feature rank

examples/feature-rank/main.go

@@ -0,0 +1,47 @@
+// This example shows how to use the feature ranking.
+package main
+
+import (
+	"fmt"
+
+	"github.com/go-gst/go-gst/examples"
+	"github.com/go-gst/go-gst/gst"
+)
+
+func start() (error) {
+	gst.Init(nil)
+
+	registry := gst.GetRegistry()
+
+	higherThanHighRank := (gst.Rank)(258)
+
+	codec, codecErr := registry.LookupFeature("vtdec_hw")
+
+	if codecErr == nil {
+		codec.SetPluginRank(higherThanHighRank)
+		rank := codec.GetPluginRank()
+		fmt.Println("vtdec_hw rank is:", rank)
+	}
+
+	codec, codecErr = registry.LookupFeature("vtdec_hw")
+
+	if codecErr == nil {
+		codec.SetPluginRank(gst.RankPrimary)
+		rank := codec.GetPluginRank()
+		fmt.Println("vtdec_hw rank is now:", rank)
+	}
+
+	//add a feature you expect to be available to you here and change it's rank
+
+	return codecErr
+}
+
+func main() {
+	examples.Run(func() error {
+		var err error
+		if err = start(); err != nil {
+			return err
+		}
+		return nil
+	})
+}

gst/constants.go

@@ -490,6 +490,16 @@ const (
 	PadProbeTypeScheduling      PadProbeType = C.GST_PAD_PROBE_TYPE_SCHEDULING       // (12288) – probe push and pull
 )
 
+// Rank casts GstRank
+type Rank uint
+
+const (
+	RankNone      Rank = C.GST_RANK_NONE      // (0) - will be chosen last or not at all
+	RankMarginal  Rank = C.GST_RANK_MARGINAL  // (64) – unlikely to be chosen
+	RankSecondary Rank = C.GST_RANK_SECONDARY // (128) – likely to be chosen
+	RankPrimary   Rank = C.GST_RANK_PRIMARY   // (256) – will be chosen first
+)
+
 // SchedulingFlags casts GstSchedulingFlags
 type SchedulingFlags int
 

gst/gst_element.go

@@ -100,14 +100,6 @@ func ElementUnlinkMany(elems ...*Element) {
 	}
 }
 
-// Rank represents a level of importance when autoplugging elements.
-type Rank uint
-
-// For now just a single RankNone is provided
-const (
-	RankNone Rank = 0
-)
-
 // RegisterElement creates a new elementfactory capable of instantiating objects of the given GoElement
 // and adds the factory to the plugin. A higher rank means more importance when autoplugging.
 func RegisterElement(plugin *Plugin, name string, rank Rank, elem glib.GoObjectSubclass, extends glib.Extendable, interfaces ...glib.Interface) bool {

gst/gst_plugin_feature.go

@@ -30,3 +30,12 @@ func (p *PluginFeature) GetPluginName() string {
 	}
 	return C.GoString(pluginName)
 }
+
+func (p *PluginFeature) SetPluginRank(rank Rank) {
+	C.gst_plugin_feature_set_rank((*C.GstPluginFeature)(p.Instance()), C.guint(rank))
+}
+
+func (p *PluginFeature) GetPluginRank() int {
+	rank := C.gst_plugin_feature_get_rank((*C.GstPluginFeature)(p.Instance()))
+	return int(rank)
+}