From d33ab5bec6cd2f37b93180aa7bb8407d12f5afc7 Mon Sep 17 00:00:00 2001
From: aler9 <46489434+aler9@users.noreply.github.com>
Date: Thu, 19 Nov 2020 14:02:31 +0100
Subject: [PATCH] drastically improve performance when reading streams with UDP

---
 internal/serverudp/server.go | 30 +++++++-----------------------
 1 file changed, 7 insertions(+), 23 deletions(-)

diff --git a/internal/serverudp/server.go b/internal/serverudp/server.go
index cb708dc7..94efa768 100644
--- a/internal/serverudp/server.go
+++ b/internal/serverudp/server.go
@@ -24,11 +24,6 @@ type publisherData struct {
 	trackId   int
 }
 
-type bufAddrPair struct {
-	buf  []byte
-	addr *net.UDPAddr
-}
-
 // Parent is implemented by program.
 type Parent interface {
 	Log(string, ...interface{})
@@ -59,9 +54,7 @@ type Server struct {
 	readBuf         *multibuffer.MultiBuffer
 	publishersMutex sync.RWMutex
 	publishers      map[publisherAddr]*publisherData
-
-	// in
-	write chan bufAddrPair
+	writeMutex      sync.Mutex
 
 	// out
 	done chan struct{}
@@ -86,7 +79,6 @@ func New(writeTimeout time.Duration,
 		pc:           pc,
 		readBuf:      multibuffer.New(2, readBufferSize),
 		publishers:   make(map[publisherAddr]*publisherData),
-		write:        make(chan bufAddrPair),
 		done:         make(chan struct{}),
 	}
 
@@ -111,15 +103,6 @@ func (s *Server) Close() {
 func (s *Server) run() {
 	defer close(s.done)
 
-	writerDone := make(chan struct{})
-	go func() {
-		defer close(writerDone)
-		for w := range s.write {
-			s.pc.SetWriteDeadline(time.Now().Add(s.writeTimeout))
-			s.pc.WriteTo(w.buf, w.addr)
-		}
-	}()
-
 	for {
 		buf := s.readBuf.Next()
 		n, addr, err := s.pc.ReadFromUDP(buf)
@@ -142,9 +125,6 @@ func (s *Server) run() {
 			pubData.publisher.OnUdpPublisherFrame(pubData.trackId, s.streamType, buf[:n])
 		}()
 	}
-
-	close(s.write)
-	<-writerDone
 }
 
 // Port returns the server local port.
@@ -153,8 +133,12 @@ func (s *Server) Port() int {
 }
 
 // Write writes a UDP packet.
-func (s *Server) Write(data []byte, addr *net.UDPAddr) {
-	s.write <- bufAddrPair{data, addr}
+func (s *Server) Write(buf []byte, addr *net.UDPAddr) {
+	s.writeMutex.Lock()
+	defer s.writeMutex.Unlock()
+
+	s.pc.SetWriteDeadline(time.Now().Add(s.writeTimeout))
+	s.pc.WriteTo(buf, addr)
 }
 
 // AddPublisher adds a publisher.