Implement RTMP buffer on the session

Author: geekgonecrazy

controllers/myStreamer.go

@@ -51,7 +51,7 @@ func GetMyStreamerHandler(c echo.Context) error {
 
 	session, _ := sessions.GetSession(streamKey)
 
-	if session != nil && session.Active {
+	if session != nil && session.Running {
 		myStreamer.Live = true
 	}
 

rtmpConnectionHandler.go

@@ -6,7 +6,6 @@ import (
 	"log"
 	"os"
 	"strings"
-	"time"
 
 	"github.com/geekgonecrazy/prismplus/sessions"
 	"github.com/geekgonecrazy/prismplus/streamers"
@@ -41,62 +40,35 @@ func rtmpConnectionHandler(conn *rtmp.Conn) {
 		os.Exit(1)
 	}
 
-	// Mark session as active and stash headers for replay on new destinations
-	session.ChangeState(true) // Mark active
+	packet, err := conn.ReadPacket()
+	if err != nil {
+		fmt.Println("can't read packet:", err)
+	}
+
+	session.SetBufferSize(packet)
+
+	// stash headers for replay on new destinations
 	session.SetHeaders(streams)
 
-	log.Println("RTMP connection now active for session", key)
+	go session.Run()
 
-	for _, destination := range session.Destinations {
-		if err := destination.RTMP.WriteHeader(streams); err != nil {
-			fmt.Println("can't write header to destination stream:", err)
-			// os.Exit(1)
-		}
-		go destination.RTMP.Loop()
-	}
+	log.Println("RTMP connection now active for session", key)
 
-	lastTime := time.Now()
 	for {
-		if session.End {
-			fmt.Printf("Ending session %s\n", key)
-			break
-		}
-
 		packet, err := conn.ReadPacket()
 		if err != nil {
 			fmt.Println("can't read packet:", err)
 			break
 		}
 
-		if time.Since(lastTime) > time.Second {
-			fmt.Println("Duration:", packet.Time)
-			lastTime = time.Now()
-		}
-
-		for _, destination := range session.Destinations {
-			destination.RTMP.WritePacket(packet)
-		}
-	}
-
-	session.ChangeState(false) // Mark inactive
-
-	for _, destination := range session.Destinations {
-		err := destination.RTMP.Disconnect()
-		if err != nil {
-			fmt.Println(err)
-			os.Exit(1)
-		}
+		session.RelayPacket(packet)
 	}
 
-	if session.End {
-		fmt.Printf("Session %s ended\n", key)
-		// Make sure we are closed
-		if err := conn.Close(); err != nil {
-			log.Println(err)
-		}
+	session.StreamDisconnected()
+	log.Println("Not processing any more.  RTMP relaying stopped")
 
-		if err := sessions.DeleteSession(key); err != nil {
-			log.Println(err)
-		}
+	// Make sure we are closed
+	if err := conn.Close(); err != nil {
+		log.Println(err)
 	}
 }

sessions/session.go

@@ -6,6 +6,7 @@ import (
 	"log"
 	"strings"
 	"sync"
+	"time"
 
 	"github.com/geekgonecrazy/prismplus/models"
 	"github.com/geekgonecrazy/prismplus/rtmp"
@@ -17,16 +18,35 @@ var (
 	ErrNotFound = errors.New("not found")
 )
 
+type StreamState uint8
+
+const (
+	StreamCreated StreamState = iota
+	StreamPacketReceived
+	StreamBuffering
+	StreamStreaming
+	StreamDisconnected
+)
+
 type Session struct {
-	StreamerID        int                  `json:"streamerId"`
-	Key               string               `json:"key"`
-	Destinations      map[int]*Destination `json:"destinations"`
-	Delay             int                  `json:"delay"`
-	NextDestinationID int                  `json:"nextDestinationId"`
-	Active            bool                 `json:"active"`
-	End               bool                 `json:"end"`
-	StreamHeaders     []av.CodecData       `json:"streamHeaders"`
-	_lock             sync.Mutex           // Might need if we allow modify
+	StreamerID               int                  `json:"streamerId"`
+	Key                      string               `json:"key"`
+	Destinations             map[int]*Destination `json:"destinations"`
+	Delay                    int                  `json:"delay"`
+	NextDestinationID        int                  `json:"nextDestinationId"`
+	Running                  bool                 `json:"running"`
+	streamHeaders            []av.CodecData       `json:"streamHeaders"`
+	streamStatus             StreamState
+	buffer                   chan av.Packet
+	incomingDuration         time.Duration
+	previousIncomingDuration time.Duration
+	bufferedDuration         time.Duration
+	outgoingDuration         time.Duration
+	bufferLength             time.Duration
+	lastPacketTime           time.Time //lastPacketTime is currently only used to help with verbose logging, don't use for any logic
+	discrepancySize          time.Duration
+	stop                     chan bool
+	_lock                    sync.Mutex // Might need if we allow modify
 }
 
 type Destination struct {
@@ -59,8 +79,8 @@ func (s *Session) AddDestination(destinationPayload models.Destination) error {
 		RTMP:   conn,
 	}
 
-	if s.Active {
-		if err := conn.WriteHeader(s.StreamHeaders); err != nil {
+	if s.Running {
+		if err := conn.WriteHeader(s.streamHeaders); err != nil {
 			fmt.Println("can't write header:", err)
 			// os.Exit(1)
 		}
@@ -103,16 +123,159 @@ func (s *Session) RemoveDestination(id int) error {
 	return nil
 }
 
-func (s *Session) ChangeState(active bool) {
-	s.Active = active
+func (s *Session) SetHeaders(streams []av.CodecData) {
+	s.streamHeaders = streams
 }
 
-func (s *Session) SetHeaders(streams []av.CodecData) {
-	s.StreamHeaders = streams
+func (s *Session) Run() {
+	// Prevent another routine from running
+	if s.Running {
+		return
+	}
+
+	// TODO: Sessions once ended actually shouldn't be removed
+	// Reset in case the session is reused
+	s.lastPacketTime = time.Now()
+	s.bufferedDuration = time.Duration(0)
+	s.outgoingDuration = time.Duration(0)
+	s.incomingDuration = time.Duration(0)
+
+	s.Running = true
+	s.streamStatus = StreamBuffering
+	log.Println("Session switched to buffering")
+
+	// Loop waiting for buffering to finish
+	for {
+		if s.streamStatus == StreamDisconnected {
+			log.Println("Stopping buffer due to disconnect")
+			break
+		}
+
+		if time.Since(s.lastPacketTime) > time.Second {
+			log.Printf("Buffered packets: %s/%s Buffered Packets: %d", s.bufferedDuration, s.bufferLength, len(s.buffer))
+			s.lastPacketTime = time.Now()
+		}
+
+		if s.incomingDuration >= s.bufferLength {
+			log.Println("Session switched to streaming", len(s.buffer))
+			s.streamStatus = StreamStreaming
+			break
+		}
+	}
+
+	if s.streamStatus == StreamStreaming {
+		log.Println("Finished Buffering")
+
+		log.Println("Connecting to destinations")
+		for _, destination := range s.Destinations {
+			if err := destination.RTMP.WriteHeader(s.streamHeaders); err != nil {
+				fmt.Println("can't write header to destination stream:", err)
+				// os.Exit(1)
+			}
+
+			go destination.RTMP.Loop()
+		}
+
+		log.Println("Beginning to stream to destinations")
+
+		streamedTime := time.Now()
+
+	Loop:
+		for {
+
+			select {
+			case <-s.stop:
+				break Loop
+			case packet := <-s.buffer:
+				// Use the timing in the packet - the time streamed to figure out when next packet should go out
+				time.Sleep(packet.Time - s.outgoingDuration)
+
+				// Verbose logging just to be able to see the state of the buffer
+				if time.Since(streamedTime) > time.Second {
+					log.Printf("Outgoing Packet Time: %s (idx %d); Incoming Packet Time: %s; Buffered up to Time: %s; Buffered Packets: %d", packet.Time, packet.Idx, s.incomingDuration, s.bufferedDuration, len(s.buffer))
+
+					streamedTime = time.Now()
+				}
+
+				// Write packet out to all destinations
+				for _, destination := range s.Destinations {
+					destination.RTMP.WritePacket(packet)
+				}
+
+				// Update with the time marker that has been already streamed
+				s.outgoingDuration = packet.Time
+				s.lastPacketTime = time.Now()
+			}
+
+			if s.streamStatus == StreamDisconnected && len(s.buffer) == 0 {
+				log.Println("Stream is disconnected and buffer is empty.  Sending Stop Signal")
+				s.stop <- true
+			}
+		}
+	}
+
+	log.Println("Disconnecting from destinations")
+	for _, destination := range s.Destinations {
+		err := destination.RTMP.Disconnect()
+		if err != nil {
+			fmt.Println(err)
+		}
+	}
+
+	s.Running = false
+
+	log.Println("Attempt to self destruct session")
+	if err := DeleteSession(s.Key); err != nil {
+		log.Println(err)
+	}
+}
+
+func (s *Session) SetBufferSize(packet av.Packet) error {
+	if s.Running && s.streamStatus != StreamCreated {
+		log.Println("Can't set Packet size for buffer while session is running")
+		s.RelayPacket(packet)
+		return nil
+	}
+
+	packetsNeeded := s.bufferLength / packet.CompositionTime
+	size := int(packetsNeeded) * 4
+
+	log.Println("Packet size:", packet.CompositionTime)
+
+	log.Println("Setting buffer size to:", size)
+
+	// Need to figure out how to do this properly again with math
+	s.buffer = make(chan av.Packet, 100000)
+
+	s.RelayPacket(packet)
+
+	return nil
+}
+
+func (s *Session) RelayPacket(p av.Packet) {
+	packetDuration := p.Time
+
+	if s.discrepancySize+packetDuration < s.previousIncomingDuration {
+		s.discrepancySize = s.bufferedDuration
+		log.Println("Discrepancy detected correcting", s.discrepancySize)
+	}
+
+	s.incomingDuration = packetDuration
+
+	p.Time = s.discrepancySize + packetDuration
+
+	s.bufferedDuration = p.Time
+	s.previousIncomingDuration = p.Time
+
+	s.buffer <- p
+}
+
+func (s *Session) StreamDisconnected() {
+	s.streamStatus = StreamDisconnected
 }
 
 func (s *Session) EndSession() {
-	s.End = true
+	s.stop <- true
 }
 
 func InitializeSessionStore() {
@@ -127,16 +290,21 @@ func CreateSession(sessionPayload models.SessionPayload) error {
 	}
 
 	if existingSession != nil {
-		return errors.New("Already Exists")
+		return errors.New("session already Exists")
 	}
 
+	bufferLength := time.Second * time.Duration(sessionPayload.Delay)
+
 	session := &Session{
+		Delay:             sessionPayload.Delay,
 		StreamerID:        sessionPayload.StreamerID,
 		Key:               sessionPayload.Key,
 		Destinations:      map[int]*Destination{},
 		NextDestinationID: 0,
-		Active:            false,
-		End:               false,
+		Running:           false,
+		buffer:            make(chan av.Packet, 1),
+		stop:              make(chan bool, 1),
+		bufferLength:      bufferLength,
 	}
 
 	_sessions[sessionPayload.Key] = session