pion

pion.go

package net

import (
	"context"
	"fmt"
	"io"
	"bufio"
	"log"
	"os"
	"time"
	"strings"
	"encoding/base64"
	"encoding/json"
	"github.com/pion/webrtc/v3"
	"github.com/pion/webrtc/v3/pkg/media"
)

func SendWebRTC(h264 chan[]byte, offer webrtc.SessionDescription) {
	peerConnection, err := webrtc.NewPeerConnection(webrtc.Configuration{
		ICEServers: []webrtc.ICEServer{
			{
				URLs: []string{"stun:stun.l.google.com:19302"},
			},
		},
	})

	if err != nil {
		panic(err)
	}

	// Create a video track
	videoTrack, err := webrtc.NewTrackLocalStaticSample(webrtc.RTPCodecCapability{MimeType: "video/h264"}, "video", "pion")
	if err != nil {
		panic(err)
	}
	sender, err := peerConnection.AddTrack(videoTrack)
	log.Printf("sender %s", sender)
	if err != nil {
		panic(err)
	}

	iceConnectedCtx, iceConnectedCtxCancel := context.WithCancel(context.Background())
	go func() {
		// Wait for connection established
		<-iceConnectedCtx.Done()
		log.Println("done")

		for {
			select {
			case frame := <-h264:
				log.Println("passing frame")
				if ivfErr := videoTrack.WriteSample(media.Sample{Data: frame, Duration: time.Second}); ivfErr != nil {
					panic(ivfErr)
				}
			}
		}
	}()

	// 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("Connection State has changed %s \n", connectionState.String())
		if connectionState == webrtc.ICEConnectionStateConnected {
			iceConnectedCtxCancel()
		}
	})

	// Set the remote SessionDescription
	if err = peerConnection.SetRemoteDescription(offer); err != nil {
		panic(err)
	}

	// Create answer
	answer, err := peerConnection.CreateAnswer(nil)
	if err != nil {
		panic(err)
	}

	// Create channel that is blocked until ICE Gathering is complete
	gatherComplete := webrtc.GatheringCompletePromise(peerConnection)

	// Sets the LocalDescription, and starts our UDP listeners
	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

	// Output the answer in base64 so we can paste it in browser
	fmt.Println(Encode(*peerConnection.LocalDescription()))
}

// Encode encodes the input in base64
// It can optionally zip the input before encoding
func Encode(obj interface{}) string {
	b, err := json.Marshal(obj)
	if err != nil {
		panic(err)
	}

	return base64.StdEncoding.EncodeToString(b)
}

func Decode(in string, obj interface{}) {
	b, err := base64.StdEncoding.DecodeString(in)
	if err != nil {
		panic(err)
	}

	err = json.Unmarshal(b, obj)
	if err != nil {
		panic(err)
	}
}

func MustReadStdin() string {
	r := bufio.NewReader(os.Stdin)

	var in string
	for {
		var err error
		in, err = r.ReadString('\n')
		if err != io.EOF {
			if err != nil {
				panic(err)
			}
		}
		in = strings.TrimSpace(in)
		if len(in) > 0 {
			break
		}
	}

	fmt.Println("")

	return in
}