client: support writing to ONVIF back channels (#101) (#462)

2025-09-27 03:25:52 +08:00 · 2023-11-15 13:20:29 +01:00
parent aaef8c29a7
commit f78b04cf4e
9 changed files with 414 additions and 92 deletions
--- a/examples/client-play-backchannel/main.go
+++ b/examples/client-play-backchannel/main.go
@@ -0,0 +1,122 @@
+package main
+
+import (
+	"log"
+	"net"
+
+	"github.com/bluenviron/gortsplib/v4"
+	"github.com/bluenviron/gortsplib/v4/pkg/base"
+	"github.com/bluenviron/gortsplib/v4/pkg/description"
+	"github.com/bluenviron/gortsplib/v4/pkg/format"
+	"github.com/pion/rtp"
+)
+
+// This example shows how to
+// 1. generate RTP/G711 packets with GStreamer
+// 2. connect to a RTSP server, find a back channel that supports G711
+// 3. route the packets from GStreamer to the channel
+
+func findPCMUBackChannel(desc *description.Session) *description.Media {
+	for _, media := range desc.Medias {
+		if media.IsBackChannel {
+			for _, forma := range media.Formats {
+				if g711, ok := forma.(*format.G711); ok {
+					if g711.MULaw {
+						return media
+					}
+				}
+			}
+		}
+	}
+	return nil
+}
+
+func main() {
+	// open a listener to receive RTP/G711 packets
+	pc, err := net.ListenPacket("udp", "localhost:9000")
+	if err != nil {
+		panic(err)
+	}
+	defer pc.Close()
+
+	log.Println("Waiting for a RTP/G711 stream on UDP port 9000 - you can generate one with GStreamer:\n\n" +
+		"* audio from a test sine:\n\n" +
+		"gst-launch-1.0 audiotestsrc freq=300 ! audioconvert ! audioresample ! audio/x-raw,rate=8000" +
+		" ! mulawenc ! rtppcmupay ! udpsink host=127.0.0.1 port=9000\n\n" +
+		"* audio from a file:\n\n" +
+		"gst-launch-1.0 filesrc location=my_file.mp4 ! decodebin ! audioconvert ! audioresample ! audio/x-raw,rate=8000" +
+		" ! mulawenc ! rtppcmupay ! udpsink host=127.0.0.1 port=9000\n\n" +
+		"* audio from a microphone:\n\n" +
+		"gst-launch-1.0 pulsesrc ! audioconvert ! audioresample ! audio/x-raw,rate=8000" +
+		" ! mulawenc ! rtppcmupay ! udpsink host=127.0.0.1 port=9000\n")
+
+	// wait for first packet
+	buf := make([]byte, 2048)
+	n, _, err := pc.ReadFrom(buf)
+	if err != nil {
+		panic(err)
+	}
+	log.Println("stream connected")
+
+	c := gortsplib.Client{
+		RequestBackChannels: true,
+	}
+
+	// parse URL
+	u, err := base.ParseURL("rtsp://localhost:8554/mystream")
+	if err != nil {
+		panic(err)
+	}
+
+	// connect to the server
+	err = c.Start(u.Scheme, u.Host)
+	if err != nil {
+		panic(err)
+	}
+	defer c.Close()
+
+	// find published medias
+	desc, _, err := c.Describe(u)
+	if err != nil {
+		panic(err)
+	}
+
+	// find the back channel
+	medi := findPCMUBackChannel(desc)
+	if medi == nil {
+		panic("media not found")
+	}
+
+	// setup a single media
+	_, err = c.Setup(desc.BaseURL, medi, 0, 0)
+	if err != nil {
+		panic(err)
+	}
+
+	// start playing
+	_, err = c.Play(nil)
+	if err != nil {
+		panic(err)
+	}
+
+	var pkt rtp.Packet
+	for {
+		// parse RTP packet
+		err = pkt.Unmarshal(buf[:n])
+		if err != nil {
+			panic(err)
+		}
+
+		// route RTP packet to the server
+		err = c.WritePacketRTP(medi, &pkt)
+		if err != nil {
+			panic(err)
+		}
+
+		// read another RTP packet from source
+		n, _, err = pc.ReadFrom(buf)
+		if err != nil {
+			panic(err)
+		}
+	}
+}