allow setting additional properties of streams through description.Stream

pkg/description/session.go

@@ -0,0 +1,83 @@
+package description
+
+import (
+	"fmt"
+
+	psdp "github.com/pion/sdp/v3"
+
+	"github.com/bluenviron/gortsplib/v4/pkg/sdp"
+	"github.com/bluenviron/gortsplib/v4/pkg/url"
+)
+
+// Session is the description of a RTSP session.
+type Session struct {
+	// base URL of the stream (read only).
+	BaseURL *url.URL
+
+	// available media streams.
+	Medias []*Media
+}
+
+// FindFormat finds a certain format among all the formats in all the medias of the stream.
+// If the format is found, it is inserted into forma, and its media is returned.
+func (d *Session) FindFormat(forma interface{}) *Media {
+	for _, media := range d.Medias {
+		ok := media.FindFormat(forma)
+		if ok {
+			return media
+		}
+	}
+	return nil
+}
+
+// Unmarshal decodes the description from SDP.
+func (d *Session) Unmarshal(ssd *sdp.SessionDescription) error {
+	d.Medias = make([]*Media, len(ssd.MediaDescriptions))
+
+	for i, md := range ssd.MediaDescriptions {
+		var m Media
+		err := m.Unmarshal(md)
+		if err != nil {
+			return fmt.Errorf("media %d is invalid: %v", i+1, err)
+		}
+		d.Medias[i] = &m
+	}
+
+	return nil
+}
+
+// Marshal encodes the description in SDP.
+func (d Session) Marshal(multicast bool) ([]byte, error) {
+	var address string
+	if multicast {
+		address = "224.1.0.0"
+	} else {
+		address = "0.0.0.0"
+	}
+
+	sout := &sdp.SessionDescription{
+		SessionName: psdp.SessionName("Session"),
+		Origin: psdp.Origin{
+			Username:       "-",
+			NetworkType:    "IN",
+			AddressType:    "IP4",
+			UnicastAddress: "127.0.0.1",
+		},
+		// required by Darwin Sessioning Server
+		ConnectionInformation: &psdp.ConnectionInformation{
+			NetworkType: "IN",
+			AddressType: "IP4",
+			Address:     &psdp.Address{Address: address},
+		},
+		TimeDescriptions: []psdp.TimeDescription{
+			{Timing: psdp.Timing{StartTime: 0, StopTime: 0}},
+		},
+		MediaDescriptions: make([]*psdp.MediaDescription, len(d.Medias)),
+	}
+
+	for i, media := range d.Medias {
+		sout.MediaDescriptions[i] = media.Marshal()
+	}
+
+	return sout.Marshal()
+}