snapshot of https://github.com/pion/webrtc.git (main, 2026-09-15; blobs > 131072B omitted)

examples/play-from-disk-renegotiation/main.go

@@ -0,0 +1,215 @@
+// SPDX-FileCopyrightText: 2026 The Pion community <https://pion.ly>
+// SPDX-License-Identifier: MIT
+
+//go:build !js
+
+// play-from-disk-renegotiation demonstrates Pion WebRTC's renegotiation abilities.
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/pion/randutil"
+	"github.com/pion/webrtc/v4"
+	"github.com/pion/webrtc/v4/pkg/media"
+	"github.com/pion/webrtc/v4/pkg/media/ivfreader"
+)
+
+var peerConnection *webrtc.PeerConnection //nolint
+
+// doSignaling exchanges all state of the local PeerConnection and is called
+// every time a video is added or removed.
+func doSignaling(res http.ResponseWriter, req *http.Request) {
+	var offer webrtc.SessionDescription
+	if err := json.NewDecoder(req.Body).Decode(&offer); err != nil {
+		panic(err)
+	}
+
+	if err := peerConnection.SetRemoteDescription(offer); err != nil {
+		panic(err)
+	}
+
+	// Create channel that is blocked until ICE Gathering is complete
+	gatherComplete := webrtc.GatheringCompletePromise(peerConnection)
+
+	answer, err := peerConnection.CreateAnswer(nil)
+	if err != nil {
+		panic(err)
+	} else if err = peerConnection.SetLocalDescription(answer); err != nil {
+		panic(err)
+	}
+
+	// Block until ICE Gathering is complete, disabling trickle ICE
+	// we do this because we only can exchange one signaling message
+	// in a production application you should exchange ICE Candidates via OnICECandidate
+	<-gatherComplete
+
+	response, err := json.Marshal(*peerConnection.LocalDescription())
+	if err != nil {
+		panic(err)
+	}
+
+	res.Header().Set("Content-Type", "application/json")
+	if _, err := res.Write(response); err != nil {
+		panic(err)
+	}
+}
+
+// Add a single video track.
+func createPeerConnection(res http.ResponseWriter, req *http.Request) {
+	if peerConnection.ConnectionState() != webrtc.PeerConnectionStateNew {
+		panic(fmt.Sprintf("createPeerConnection called in non-new state (%s)", peerConnection.ConnectionState()))
+	}
+
+	doSignaling(res, req)
+	fmt.Println("PeerConnection has been created")
+}
+
+// Add a single video track.
+func addVideo(res http.ResponseWriter, req *http.Request) { //nolint:cyclop
+	// Open a IVF file and start reading using our IVFReader
+	file, err := os.Open("output.ivf")
+	if err != nil {
+		panic(err)
+	}
+
+	ivf, header, err := ivfreader.NewWith(file)
+	if err != nil {
+		panic(err)
+	}
+
+	var mimeType string
+	switch header.FourCC {
+	case "VP80":
+		mimeType = webrtc.MimeTypeVP8
+	case "VP90":
+		mimeType = webrtc.MimeTypeVP9
+	case "AV01":
+		mimeType = webrtc.MimeTypeAV1
+	default:
+		panic(fmt.Sprintf("unsupported codec: %s", header.FourCC))
+	}
+
+	videoTrack, err := webrtc.NewTrackLocalStaticSample(
+		webrtc.RTPCodecCapability{MimeType: mimeType},
+		fmt.Sprintf("video-%d", randutil.NewMathRandomGenerator().Uint32()),
+		fmt.Sprintf("video-%d", randutil.NewMathRandomGenerator().Uint32()),
+	)
+	if err != nil {
+		panic(err)
+	}
+	rtpSender, err := peerConnection.AddTrack(videoTrack)
+	if err != nil {
+		panic(err)
+	}
+
+	// Read incoming RTCP packets
+	// Before these packets are returned they are processed by interceptors. For things
+	// like NACK this needs to be called.
+	go func() {
+		rtcpBuf := make([]byte, 1500)
+		for {
+			if _, _, rtcpErr := rtpSender.Read(rtcpBuf); rtcpErr != nil {
+				return
+			}
+		}
+	}()
+
+	doSignaling(res, req)
+	fmt.Println("Video track has been added")
+	go writeVideoToTrack(ivf, header, videoTrack)
+}
+
+// Remove a single sender.
+func removeVideo(res http.ResponseWriter, req *http.Request) {
+	if senders := peerConnection.GetSenders(); len(senders) != 0 {
+		if err := peerConnection.RemoveTrack(senders[0]); err != nil {
+			panic(err)
+		}
+	}
+
+	doSignaling(res, req)
+	fmt.Println("Video track has been removed")
+}
+
+func main() {
+	var err error
+	if peerConnection, err = webrtc.NewPeerConnection(webrtc.Configuration{}); err != nil {
+		panic(err)
+	}
+	defer func() {
+		if cErr := peerConnection.Close(); cErr != nil {
+			fmt.Printf("cannot close peerConnection: %v\n", cErr)
+		}
+	}()
+
+	// Set the handler for Peer connection state
+	// This will notify you when the peer has connected/disconnected
+	peerConnection.OnConnectionStateChange(func(state webrtc.PeerConnectionState) {
+		fmt.Printf("Peer Connection State has changed: %s\n", state.String())
+
+		if state == webrtc.PeerConnectionStateFailed {
+			// Wait until PeerConnection has had no network activity for 30 seconds or another failure.
+			// It may be reconnected using an ICE Restart.
+			// Use webrtc.PeerConnectionStateDisconnected if you are interested in detecting faster timeout.
+			// Note that the PeerConnection may come back from PeerConnectionStateDisconnected.
+			fmt.Println("Peer Connection has gone to failed exiting")
+			os.Exit(0)
+		}
+
+		if state == webrtc.PeerConnectionStateClosed {
+			// PeerConnection was explicitly closed. This usually happens from a DTLS CloseNotify
+			fmt.Println("Peer Connection has gone to closed exiting")
+			os.Exit(0)
+		}
+	})
+
+	http.Handle("/", http.FileServer(http.Dir(".")))
+	http.HandleFunc("/createPeerConnection", createPeerConnection)
+	http.HandleFunc("/addVideo", addVideo)
+	http.HandleFunc("/removeVideo", removeVideo)
+
+	go func() {
+		fmt.Println("Open http://localhost:8080 to access this demo")
+		// nolint: gosec
+		panic(http.ListenAndServe(":8080", nil))
+	}()
+
+	// Block forever
+	select {}
+}
+
+// Read a video file from disk and write it to a webrtc.Track
+// When the video has been completely read this exits without error.
+func writeVideoToTrack(
+	ivf *ivfreader.IVFReader, header *ivfreader.IVFFileHeader, track *webrtc.TrackLocalStaticSample,
+) {
+	// Send our video file frame at a time. Pace our sending so we send it at the same speed it should be played back as.
+	// This isn't required since the video is timestamped, but we will such much higher loss if we send all at once.
+	//
+	// It is important to use a time.Ticker instead of time.Sleep because
+	// * avoids accumulating skew, just calling time.Sleep didn't compensate for the time spent parsing the data
+	// * works around latency issues with Sleep (see https://github.com/golang/go/issues/44343)
+	ticker := time.NewTicker(
+		time.Millisecond * time.Duration((float32(header.TimebaseNumerator)/float32(header.TimebaseDenominator))*1000),
+	)
+	defer ticker.Stop()
+	for ; true; <-ticker.C {
+		frame, _, err := ivf.ParseNextFrame()
+		if err != nil {
+			fmt.Printf("Finish writing video track: %s ", err)
+
+			return
+		}
+
+		if err = track.WriteSample(media.Sample{Data: frame, Duration: time.Second}); err != nil {
+			fmt.Printf("Finish writing video track: %s ", err)
+
+			return
+		}
+	}
+}