main.go

package main

import (
	"encoding/json"
	"log"
	"math/rand"
	"net/http"
	"time"

	"github.com/pion/webrtc/v3"
)

func main() {
	rand.Seed(time.Now().UTC().UnixNano())

	http.Handle("/", http.FileServer(http.Dir(".")))
	http.HandleFunc("/createPeerConnection", createPeerConnection)
	panic(http.ListenAndServe(":8080", nil))
}

// Add a single video track
func createPeerConnection(w http.ResponseWriter, r *http.Request) {
	log.Println("Incoming HTTP Request")

	peerConnection, err := webrtc.NewPeerConnection(webrtc.Configuration{})
	if err != nil {
		panic(err)
	}

	videoTrack, err := webrtc.NewTrackLocalStaticSample(webrtc.RTPCodecCapability{MimeType: webrtc.MimeTypeH264}, "video", "pion")
	if err != nil {
		panic(err)
	}
	if _, err = peerConnection.AddTrack(videoTrack); err != nil {
		panic(err)
	}

	// audioTrack, err := webrtc.NewTrackLocalStaticSample(webrtc.RTPCodecCapability{MimeType: webrtc.MimeTypePCMA}, "audio", "pion")
	audioTrack, err := webrtc.NewTrackLocalStaticSample(webrtc.RTPCodecCapability{MimeType: webrtc.MimeTypeOpus}, "audio", "pion")
	if err != nil {
		panic(err)
	}
	if _, err = peerConnection.AddTrack(audioTrack); err != nil {
		panic(err)
	}

	var offer webrtc.SessionDescription
	if err := json.NewDecoder(r.Body).Decode(&offer); err != nil {
		panic(err)
	}

	if err := peerConnection.SetRemoteDescription(offer); err != nil {
		panic(err)
	}

	gatherComplete := webrtc.GatheringCompletePromise(peerConnection)
	answer, err := peerConnection.CreateAnswer(nil)
	if err != nil {
		panic(err)
	} else if err = peerConnection.SetLocalDescription(answer); err != nil {
		panic(err)
	}
	<-gatherComplete

	response, err := json.Marshal(peerConnection.LocalDescription())
	if err != nil {
		panic(err)
	}

	w.Header().Set("Content-Type", "application/json")
	if _, err := w.Write(response); err != nil {
		panic(err)
	}

	go startRTMPServer(peerConnection, videoTrack, audioTrack)
}