ace/lib/webrtcconnection/connection.go

package webrtcconnection

import (
	"git.sense-t.eu.org/ACE/ace/servers/qemuserver"
	"github.com/pion/mediadevices"
	"github.com/pion/mediadevices/pkg/codec/opus"
	"github.com/pion/mediadevices/pkg/codec/x264"
	"github.com/pion/mediadevices/pkg/driver"
	"github.com/pion/webrtc/v3"
	"github.com/sirupsen/logrus"
)

const DefaultStreamID = "ace-server"

type Connection struct {
	option *Options
	api    *webrtc.API
	stream mediadevices.MediaStream
	QEMU   *qemuserver.Server
}

func New(o *Options) (*Connection, error) {
	connection := &Connection{
		option: o,
	}
	codecSelector, err := setupCodec(o.VideoBPS)
	if err != nil {
		return nil, err
	}

	me := &webrtc.MediaEngine{}
	codecSelector.Populate(me)

	connection.api = webrtc.NewAPI(webrtc.WithMediaEngine(me))

	logrus.Debug("list devices:")
	devices := driver.GetManager().Query(func(d driver.Driver) bool { return true })
	for _, device := range devices {
		logrus.Debug("\t", device.ID())
		logrus.Debug("\t", device.Info())
		logrus.Debug("\t", device.Properties())
		logrus.Debug("\t", device.Status())
		logrus.Debug("\t------")
	}

	s, err := mediadevices.GetUserMedia(mediadevices.MediaStreamConstraints{
		Video: func(mtc *mediadevices.MediaTrackConstraints) {},
		Audio: func(mtc *mediadevices.MediaTrackConstraints) {},
		Codec: codecSelector,
	})
	if err != nil {
		return nil, err
	}
	connection.stream = s

	return connection, nil
}

func (c *Connection) Regist(offer *webrtc.SessionDescription) (*webrtc.SessionDescription, error) {
	logrus.Debug("received offer ")

	rtc, err := c.api.NewPeerConnection(webrtc.Configuration{
		ICEServers: []webrtc.ICEServer{
			{
				URLs: c.option.STUNServers,
			},
		},
	})
	if err != nil {
		return nil, err
	}

	rtc.OnICEConnectionStateChange(func(connectionState webrtc.ICEConnectionState) {
		logrus.Debug("connection state has changed: ", connectionState.String())
	})

	rtc.OnICECandidate(func(i *webrtc.ICECandidate) {
		logrus.Debug("cadidate: ", i)
	})

	for _, track := range c.stream.GetTracks() {
		track.OnEnded(func(err error) {
			logrus.Errorf("Track (ID: %s, kind: %s) ended with error: %v", track.ID(), track.Kind().String(), err)
		})
		_, err := rtc.AddTransceiverFromTrack(track, webrtc.RTPTransceiverInit{
			Direction: webrtc.RTPTransceiverDirectionSendonly,
		})
		if err != nil {
			logrus.Error(err)
		}
	}

	rtc.OnDataChannel(c.dataChannel)

	if err := rtc.SetRemoteDescription(*offer); err != nil {
		return nil, err
	}
	logrus.Debug("offer set")

	answer, err := rtc.CreateAnswer(nil)
	if err != nil {
		return nil, err
	}

	if err := rtc.SetLocalDescription(answer); err != nil {
		return nil, err
	}
	logrus.Debug("answer set")

	<-webrtc.GatheringCompletePromise(rtc)

	defer logrus.Debug("regist complete")
	return rtc.LocalDescription(), nil
}

func setupCodec(videoBPS int) (*mediadevices.CodecSelector, error) {
	x264Prarm, err := x264.NewParams()
	if err != nil {
		return nil, err
	}
	x264Prarm.BitRate = videoBPS
	x264Prarm.Preset = x264.PresetFaster

	opusParam, err := opus.NewParams()
	if err != nil {
		return nil, err
	}

	codecSelector := mediadevices.NewCodecSelector(
		mediadevices.WithAudioEncoders(&opusParam),
		mediadevices.WithVideoEncoders(&x264Prarm),
	)
	return codecSelector, nil
}