Add bitrate to webrtc/mse/mp4 consumer info (#5)

Makefile

@@ -0,0 +1,2 @@
+dev:
+	goreload .

pkg/core/connection.go

@@ -49,6 +49,9 @@ type Connection struct {
 	Send      int         `json:"bytes_send,omitempty"`
 
 	Transport any `json:"-"`
+
+	stopBitrateWorker chan struct{} `json:"-"`
+	Bitrate           int           `json:"bitrate,omitempty"` // bytes per second
 }
 
 func (c *Connection) GetMedias() []*Media {
@@ -67,6 +70,8 @@ func (c *Connection) GetTrack(media *Media, codec *Codec) (*Receiver, error) {
 }
 
 func (c *Connection) Stop() error {
+	c.StopBitrateWorker()
+
 	for _, receiver := range c.Receivers {
 		receiver.Close()
 	}

pkg/core/custom.go

@@ -0,0 +1,29 @@
+package core
+
+import (
+	"time"
+)
+
+func (c *Connection) StartBitrateWorker() {
+	c.stopBitrateWorker = make(chan struct{}, 1)
+
+	go func() {
+		ticker := time.NewTicker(time.Second)
+		defer ticker.Stop()
+
+		prevSendBytes := c.Send
+		for {
+			select {
+			case <-ticker.C:
+				c.Bitrate = c.Send - prevSendBytes
+				prevSendBytes = c.Send
+			case <-c.stopBitrateWorker:
+				return
+			}
+		}
+	}()
+}
+
+func (c *Connection) StopBitrateWorker() {
+	c.stopBitrateWorker <- struct{}{}
+}

pkg/mp4/consumer.go

@@ -48,7 +48,7 @@ func NewConsumer(medias []*core.Media) *Consumer {
 	}
 
 	wr := core.NewWriteBuffer(nil)
-	return &Consumer{
+	cons := &Consumer{
 		Connection: core.Connection{
 			ID:         core.NewID(),
 			FormatName: "mp4",
@@ -58,6 +58,8 @@ func NewConsumer(medias []*core.Media) *Consumer {
 		muxer: &Muxer{},
 		wr:    wr,
 	}
+	cons.StartBitrateWorker()
+	return cons
 }
 
 func (c *Consumer) AddTrack(media *core.Media, _ *core.Codec, track *core.Receiver) error {

pkg/webrtc/conn.go

@@ -139,6 +139,8 @@ func NewConn(pc *webrtc.PeerConnection) *Conn {
 		}
 	})
 
+	c.StartBitrateWorker()
+
 	return c
 }
 
@@ -148,6 +150,7 @@ func (c *Conn) MarshalJSON() ([]byte, error) {
 
 func (c *Conn) Close() error {
 	c.closed.Done(nil)
+	c.StopBitrateWorker()
 	return c.pc.Close()
 }