ghostream/stream/webrtc/webrtc.go

260 lines
7.8 KiB
Go

package webrtc
import (
"fmt"
"io"
"log"
"math/rand"
"os"
"time"
"github.com/pion/webrtc/v3"
"github.com/pion/webrtc/v3/pkg/media"
"github.com/pion/webrtc/v3/pkg/media/ivfreader"
"github.com/pion/webrtc/v3/pkg/media/oggreader"
"gitlab.crans.org/nounous/ghostream/internal/monitoring"
)
// Options holds web package configuration
type Options struct {
MinPortUDP uint16
MaxPortUDP uint16
STUNServers []string
}
// SessionDescription contains SDP data
// to initiate a WebRTC connection between one client and this app
type SessionDescription = webrtc.SessionDescription
const (
audioFileName = "output.ogg"
videoFileName = "output.ivf"
)
var (
videoTracks []*webrtc.Track
audioTracks []*webrtc.Track
)
// Helper to reslice tracks
func removeTrack(tracks []*webrtc.Track, track *webrtc.Track) []*webrtc.Track {
for i, t := range tracks {
if t == track {
return append(tracks[:i], tracks[i+1:]...)
}
}
return nil
}
// GetNumberConnectedSessions get the number of currently connected clients
func GetNumberConnectedSessions() int {
return len(videoTracks)
}
// newPeerHandler is called when server receive a new session description
// this initiates a WebRTC connection and return server description
func newPeerHandler(remoteSdp webrtc.SessionDescription, cfg *Options) webrtc.SessionDescription {
// Create media engine using client SDP
mediaEngine := webrtc.MediaEngine{}
if err := mediaEngine.PopulateFromSDP(remoteSdp); err != nil {
log.Println("Failed to create new media engine", err)
return webrtc.SessionDescription{}
}
// Create a new PeerConnection
settingsEngine := webrtc.SettingEngine{}
if err := settingsEngine.SetEphemeralUDPPortRange(cfg.MinPortUDP, cfg.MaxPortUDP); err != nil {
log.Println("Failed to set min/max UDP ports", err)
return webrtc.SessionDescription{}
}
api := webrtc.NewAPI(
webrtc.WithMediaEngine(mediaEngine),
webrtc.WithSettingEngine(settingsEngine),
)
peerConnection, err := api.NewPeerConnection(webrtc.Configuration{
ICEServers: []webrtc.ICEServer{{URLs: cfg.STUNServers}},
})
if err != nil {
log.Println("Failed to initiate peer connection", err)
return webrtc.SessionDescription{}
}
// Create video track
codec, payloadType := getPayloadType(mediaEngine, webrtc.RTPCodecTypeVideo, "VP8")
videoTrack, err := webrtc.NewTrack(payloadType, rand.Uint32(), "video", "pion", codec)
if err != nil {
log.Println("Failed to create new video track", err)
return webrtc.SessionDescription{}
}
if _, err = peerConnection.AddTrack(videoTrack); err != nil {
log.Println("Failed to add video track", err)
return webrtc.SessionDescription{}
}
// Create audio track
codec, payloadType = getPayloadType(mediaEngine, webrtc.RTPCodecTypeAudio, "opus")
audioTrack, err := webrtc.NewTrack(payloadType, rand.Uint32(), "audio", "pion", codec)
if err != nil {
log.Println("Failed to create new audio track", err)
return webrtc.SessionDescription{}
}
if _, err = peerConnection.AddTrack(audioTrack); err != nil {
log.Println("Failed to add audio track", err)
return webrtc.SessionDescription{}
}
// Set the remote SessionDescription
if err = peerConnection.SetRemoteDescription(remoteSdp); err != nil {
log.Println("Failed to set remote description", err)
return webrtc.SessionDescription{}
}
// Create answer
answer, err := peerConnection.CreateAnswer(nil)
if err != nil {
log.Println("Failed to create answer", err)
return webrtc.SessionDescription{}
}
// 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 {
log.Println("Failed to set local description", err)
return webrtc.SessionDescription{}
}
// Set the handler for ICE connection state
// This will notify you when the peer has connected/disconnected
peerConnection.OnICEConnectionStateChange(func(connectionState webrtc.ICEConnectionState) {
log.Printf("Connection State has changed %s \n", connectionState.String())
if connectionState == webrtc.ICEConnectionStateConnected {
// Register tracks
videoTracks = append(videoTracks, videoTrack)
audioTracks = append(audioTracks, audioTrack)
monitoring.WebRTCConnectedSessions.Inc()
} else if connectionState == webrtc.ICEConnectionStateDisconnected {
// Unregister tracks
videoTracks = removeTrack(videoTracks, videoTrack)
audioTracks = removeTrack(audioTracks, audioTrack)
monitoring.WebRTCConnectedSessions.Dec()
}
})
// 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 local description and send it to browser
return *peerConnection.LocalDescription()
}
func playVideo() {
// Open a IVF file and start reading using our IVFReader
file, ivfErr := os.Open(videoFileName)
if ivfErr != nil {
panic(ivfErr)
}
ivf, header, ivfErr := ivfreader.NewWith(file)
if ivfErr != nil {
panic(ivfErr)
}
// Send our video file frame at a time. Pace our sending so we send it at the same speed it should be played back as.
// This isn't required since the video is timestamped, but we will such much higher loss if we send all at once.
sleepTime := time.Millisecond * time.Duration((float32(header.TimebaseNumerator)/float32(header.TimebaseDenominator))*1000)
for {
// Need at least one client
frame, _, ivfErr := ivf.ParseNextFrame()
if ivfErr == io.EOF {
fmt.Printf("All video frames parsed and sent")
os.Exit(0)
}
if ivfErr != nil {
panic(ivfErr)
}
time.Sleep(sleepTime)
for _, t := range videoTracks {
if ivfErr = t.WriteSample(media.Sample{Data: frame, Samples: 90000}); ivfErr != nil {
log.Fatalln("Failed to write video stream:", ivfErr)
}
}
}
}
func playAudio() {
// Open a IVF file and start reading using our IVFReader
file, oggErr := os.Open(audioFileName)
if oggErr != nil {
panic(oggErr)
}
// Open on oggfile in non-checksum mode.
ogg, _, oggErr := oggreader.NewWith(file)
if oggErr != nil {
panic(oggErr)
}
// Keep track of last granule, the difference is the amount of samples in the buffer
var lastGranule uint64
for {
// Need at least one client
pageData, pageHeader, oggErr := ogg.ParseNextPage()
if oggErr == io.EOF {
fmt.Printf("All audio pages parsed and sent")
os.Exit(0)
}
if oggErr != nil {
panic(oggErr)
}
// The amount of samples is the difference between the last and current timestamp
sampleCount := float64(pageHeader.GranulePosition - lastGranule)
lastGranule = pageHeader.GranulePosition
for _, t := range audioTracks {
if oggErr = t.WriteSample(media.Sample{Data: pageData, Samples: uint32(sampleCount)}); oggErr != nil {
log.Fatalln("Failed to write audio stream:", oggErr)
}
}
// Convert seconds to Milliseconds, Sleep doesn't accept floats
time.Sleep(time.Duration((sampleCount/48000)*1000) * time.Millisecond)
}
}
// Search for Codec PayloadType
//
// Since we are answering we need to match the remote PayloadType
func getPayloadType(m webrtc.MediaEngine, codecType webrtc.RTPCodecType, codecName string) (*webrtc.RTPCodec, uint8) {
for _, codec := range m.GetCodecsByKind(codecType) {
if codec.Name == codecName {
return codec, codec.PayloadType
}
}
panic(fmt.Sprintf("Remote peer does not support %s", codecName))
}
// Serve WebRTC media streaming server
func Serve(remoteSdpChan, localSdpChan chan webrtc.SessionDescription, cfg *Options) {
log.Printf("WebRTC server using UDP from %d to %d", cfg.MinPortUDP, cfg.MaxPortUDP)
go playVideo()
go playAudio()
// Handle new connections
for {
// Wait for incoming session description
// then send the local description to browser
offer := <-remoteSdpChan
localSdpChan <- newPeerHandler(offer, cfg)
}
}