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

examples/quick-switch/main.go

@@ -0,0 +1,188 @@
+// SPDX-FileCopyrightText: 2026 The Pion community <https://pion.ly>
+// SPDX-License-Identifier: MIT
+
+//go:build !js
+
+// quick-switch demonstrates Pion WebRTC's ability to quickly switch between videos.
+package main
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+	"slices"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"github.com/pion/webrtc/v4"
+	"github.com/pion/webrtc/v4/pkg/media"
+	"github.com/pion/webrtc/v4/pkg/media/ivfreader"
+)
+
+// nolint: gochecknoglobals
+var (
+	tracksLock sync.RWMutex
+	tracks     []*webrtc.TrackLocalStaticSample
+
+	videoFiles     []string
+	videoFileIndex atomic.Int32
+)
+
+func nextVideo() {
+	newIndex := videoFileIndex.Load() + 1
+	if int(newIndex) >= len(videoFiles) {
+		newIndex = 0
+	}
+
+	videoFileIndex.Store(newIndex)
+}
+
+// nolint: cyclop
+func doWHIP(res http.ResponseWriter, req *http.Request) {
+	peerConnection, err := webrtc.NewPeerConnection(webrtc.Configuration{})
+	if err != nil {
+		panic(err)
+	}
+
+	peerConnection.OnDataChannel(func(d *webrtc.DataChannel) {
+		d.OnMessage(func(_ webrtc.DataChannelMessage) {
+			nextVideo()
+		})
+	})
+
+	// One Track is used for PeerConnection. All video streams are written to one Track
+	videoTrack, err := webrtc.NewTrackLocalStaticSample(webrtc.RTPCodecCapability{
+		MimeType: webrtc.MimeTypeAV1,
+	}, "video", "video")
+	if err != nil {
+		panic(err)
+	}
+
+	if _, err = peerConnection.AddTrack(videoTrack); err != nil {
+		panic(err)
+	}
+
+	tracksLock.Lock()
+	tracks = append(tracks, videoTrack)
+	tracksLock.Unlock()
+
+	// Set the handler for ICE connection state
+	// This will notify you when the peer has connected/disconnected
+	peerConnection.OnICEConnectionStateChange(func(connectionState webrtc.ICEConnectionState) {
+		fmt.Printf("ICE Connection State has changed: %s\n", connectionState.String())
+		if connectionState == webrtc.ICEConnectionStateClosed || connectionState == webrtc.ICEConnectionStateFailed {
+			if closeErr := peerConnection.Close(); closeErr != nil {
+				panic(closeErr)
+			}
+
+			tracksLock.Lock()
+			tracks = slices.DeleteFunc(tracks, func(x *webrtc.TrackLocalStaticSample) bool { return x == videoTrack })
+			tracksLock.Unlock()
+		}
+	})
+
+	offer, err := io.ReadAll(req.Body)
+	if err != nil {
+		panic(err)
+	}
+
+	if err = peerConnection.SetRemoteDescription(webrtc.SessionDescription{
+		Type: webrtc.SDPTypeOffer,
+		SDP:  string(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
+
+	res.Header().Set("Content-Type", "application/sdp")
+	if _, err := res.Write([]byte(peerConnection.LocalDescription().SDP)); err != nil {
+		panic(err)
+	}
+}
+
+func playFile(fileIndex int32) {
+	file, err := os.Open(videoFiles[fileIndex])
+	if err != nil {
+		panic(err)
+	}
+	defer file.Close() // nolint: errcheck
+
+	ivf, header, err := ivfreader.NewWith(file)
+	if err != nil {
+		panic(err)
+	}
+
+	frameDuration := time.Duration(header.TimebaseNumerator) * time.Second / time.Duration(header.TimebaseDenominator)
+	ticker := time.NewTicker(frameDuration)
+	defer ticker.Stop()
+
+	for {
+		if fileIndex != videoFileIndex.Load() {
+			return
+		}
+
+		frame, _, err := ivf.ParseNextFrame()
+		if errors.Is(err, io.EOF) {
+			nextVideo()
+
+			return
+		} else if err != nil {
+			panic(err)
+		}
+
+		tracksLock.RLock()
+		for _, t := range tracks {
+			if err = t.WriteSample(media.Sample{Data: frame, Duration: frameDuration}); err != nil {
+				tracksLock.RUnlock()
+				panic(err)
+			}
+		}
+		tracksLock.RUnlock()
+		<-ticker.C
+	}
+}
+
+func main() {
+	http.Handle("/", http.FileServer(http.Dir(".")))
+	http.HandleFunc("/whip", doWHIP)
+
+	// Switch between all ivf files in current directory
+	go func() {
+		files, err := filepath.Glob("*.ivf")
+		if err != nil {
+			panic(err)
+		}
+		for _, p := range files {
+			videoFiles = append(videoFiles, filepath.Base(p))
+		}
+		if len(videoFiles) == 0 {
+			panic("no .ivf files found in the working directory")
+		}
+
+		for {
+			playFile(videoFileIndex.Load())
+		}
+	}()
+
+	fmt.Println("Open http://localhost:8080 to access this demo")
+	// nolint: gosec
+	panic(http.ListenAndServe(":8080", nil))
+}