webrtc: start/stop ffmpeg procees if webrtc has clients

http/rtc/webrtc.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"net"
+	"rkkvm/external/ffmpeg"
 	"sync"
 
 	"github.com/google/uuid"
@@ -37,6 +38,10 @@ func (r *RTC) AddPeer(p *webrtc.PeerConnection, offer webrtc.SessionDescription)
 	peerID := uuid.New().String()
 	r.m.Lock()
 	r.peers[peerID] = p
+	if len(r.peers) == 1 {
+		ffmpeg.GetFFmpeg().Start()
+		log.Info("FFmpeg process started")
+	}
 	r.m.Unlock()
 
 	p.OnConnectionStateChange(func(connState webrtc.PeerConnectionState) {
@@ -44,6 +49,10 @@ func (r *RTC) AddPeer(p *webrtc.PeerConnection, offer webrtc.SessionDescription)
 			r.m.Lock()
 			defer r.m.Unlock()
 			delete(r.peers, peerID)
+			if len(r.peers) == 0 {
+				ffmpeg.GetFFmpeg().Stop()
+				log.Info("No clients anymore, stop ffmpeg process")
+			}
 			p.Close()
 
 			peers := make([]string, 0, len(r.peers))