saveToMp4main.go

package main

import (
	"fmt"
	"os"
	"time"

	"github.com/pion/rtcp"
	"github.com/pion/webrtc/v2"
	"github.com/pion/webrtc/v2/pkg/media"
	"github.com/pion/webrtc/v2/pkg/media/h264writer"
	"github.com/pion/webrtc/v2/pkg/media/oggwriter"

	"github.com/pion/webrtc/v2/examples/internal/signal"
)

func saveToDisk(i media.Writer, track *webrtc.Track) {
	defer func() {
		if err := i.Close(); err != nil {
			panic(err)
		}
	}()

	for {
		rtpPacket, err := track.ReadRTP()
		if err != nil {
			panic(err)
		}
		if err := i.WriteRTP(rtpPacket); err != nil {
			panic(err)
		}
	}
}

func main() {
	// Create a MediaEngine object to configure the supported codec
	m := webrtc.MediaEngine{}

	// Setup the codecs you want to use.
	// We'll use a VP8 codec but you can also define your own
	m.RegisterCodec(webrtc.NewRTPOpusCodec(webrtc.DefaultPayloadTypeOpus, 48000))
	m.RegisterCodec(webrtc.NewRTPH264Codec(webrtc.DefaultPayloadTypeH264, 90000))

	// Create the API object with the MediaEngine
	api := webrtc.NewAPI(webrtc.WithMediaEngine(m))

	// Everything below is the Pion WebRTC API! Thanks for using it ❤️.

	// Prepare the configuration
	config := webrtc.Configuration{
		ICEServers: []webrtc.ICEServer{
			{
				URLs: []string{"stun:stun.l.google.com:19302"},
			},
		},
	}

	// Create a new RTCPeerConnection
	peerConnection, err := api.NewPeerConnection(config)
	if err != nil {
		panic(err)
	}

	// Allow us to receive 1 audio track, and 1 video track
	if _, err = peerConnection.AddTransceiverFromKind(webrtc.RTPCodecTypeAudio); err != nil {
		panic(err)
	} else if _, err = peerConnection.AddTransceiverFromKind(webrtc.RTPCodecTypeVideo); err != nil {
		panic(err)
	}

	oggFile, err := oggwriter.New("output.ogg", 48000, 2)
	if err != nil {
		panic(err)
	}
	h264File, err := h264writer.New("output.mp4")
	if err != nil {
		panic(err)
	}

	// Set a handler for when a new remote track starts, this handler saves buffers to disk as
	// an ivf file, since we could have multiple video tracks we provide a counter.
	// In your application this is where you would handle/process video
	peerConnection.OnTrack(func(track *webrtc.Track, receiver *webrtc.RTPReceiver) {
		// Send a PLI on an interval so that the publisher is pushing a keyframe every rtcpPLIInterval
		go func() {
			ticker := time.NewTicker(time.Second * 3)
			for range ticker.C {
				errSend := peerConnection.WriteRTCP([]rtcp.Packet{&rtcp.PictureLossIndication{MediaSSRC: track.SSRC()}})
				if errSend != nil {
					fmt.Println(errSend)
				}
			}
		}()

		codec := track.Codec()
		if codec.Name == webrtc.H264 {
			fmt.Println("Got H264 track, saving to disk as output.mp4")
			saveToDisk(h264File, track)
		}
		if codec.Name == webrtc.Opus {
			fmt.Println("Got Opus track, saving to disk as output.opus (48 kHz, 2 channels)")
			saveToDisk(oggFile, track)
		}
	})

	// 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 {
			fmt.Println("Ctrl+C the remote client to stop the demo")
		} else if connectionState == webrtc.ICEConnectionStateFailed ||
			connectionState == webrtc.ICEConnectionStateDisconnected {
			closeErr := oggFile.Close()
			if closeErr != nil {
				panic(closeErr)
			}

			closeErr = h264File.Close()
			if closeErr != nil {
				panic(closeErr)
			}

			fmt.Println("Done writing media files")
			os.Exit(0)
		}
	})

	// Wait for the offer to be pasted
	offer := webrtc.SessionDescription{}
	signal.Decode(signal.MustReadStdin(), &offer)

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

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

	// Sets the LocalDescription, and starts our UDP listeners
	err = peerConnection.SetLocalDescription(answer)
	if err != nil {
		panic(err)
	}

	// Output the answer in base64 so we can paste it in browser
	fmt.Println(signal.Encode(answer))

	// Block forever
	select {}
}