Added support to stream backchannel to a command (outputbc)

internal/outputbc/init.go

@@ -0,0 +1,22 @@
+package outputbc
+
+import (
+	"github.com/AlexxIT/go2rtc/internal/streams"
+	"github.com/AlexxIT/go2rtc/pkg/core"
+	"github.com/AlexxIT/go2rtc/pkg/outputbc"
+	"github.com/AlexxIT/go2rtc/pkg/shell"
+)
+
+func Init() {
+	streams.HandleFunc("outputbc", handle)
+}
+
+func handle(url string) (core.Producer, error) {
+	args := shell.QuoteSplit(url[9:])
+	con, err := outputbc.NewClient(args)
+	if err != nil {
+		return nil, err
+	}
+	con.Dial()
+	return con, nil
+}

main.go

@@ -1,6 +1,8 @@
 package main
 
 import (
+	"github.com/AlexxIT/go2rtc/internal/outputbc"
+
 	"github.com/AlexxIT/go2rtc/internal/api"
 	"github.com/AlexxIT/go2rtc/internal/api/ws"
 	"github.com/AlexxIT/go2rtc/internal/app"
@@ -80,6 +82,7 @@ func main() {
 	bubble.Init()   // bubble source
 	expr.Init()     // expr source
 	gopro.Init()    // gopro source
+	outputbc.Init()
 
 	// 6. Helper modules
 

pkg/outputbc/client.go

@@ -0,0 +1,56 @@
+package outputbc
+
+import (
+	"io"
+	"net"
+	"os/exec"
+	"sync"
+
+	"github.com/AlexxIT/go2rtc/pkg/core"
+)
+
+type Client struct {
+	medias  []*core.Media
+	sender  *core.Sender
+	conn    net.Conn
+	send    int
+	cmd     exec.Cmd
+	pipe    io.WriteCloser
+	command []string
+}
+
+var lock = &sync.Mutex{}
+var singleInstance *Client
+
+func NewClient(command []string) (*Client, error) {
+	return &Client{command: command}, nil
+}
+
+func (c *Client) Dial() {
+	media := &core.Media{
+		Kind:      core.KindAudio,
+		Direction: core.DirectionSendonly,
+		Codecs: []*core.Codec{
+			{Name: core.CodecPCMA, ClockRate: 8000},
+		},
+	}
+
+	c.medias = append(c.medias, media)
+	if c.pipe == nil {
+		cmdName := c.command[0]
+		args := c.command[1:]
+		c.cmd = *exec.Command(cmdName, args...)
+		c.pipe, _ = c.cmd.StdinPipe()
+	}
+}
+
+func (c *Client) Open() (err error) {
+	c.cmd.Run()
+	return
+}
+
+func (c *Client) Close() (err error) {
+	c.pipe.Close()
+	c.cmd.Process.Kill()
+	return
+}

pkg/outputbc/consumer.go

@@ -0,0 +1,62 @@
+package outputbc
+
+import (
+	"encoding/json"
+
+	"github.com/AlexxIT/go2rtc/pkg/core"
+	"github.com/pion/rtp"
+)
+
+func (c *Client) GetMedias() []*core.Media {
+	return c.medias
+}
+
+func (c *Client) GetTrack(media *core.Media, codec *core.Codec) (*core.Receiver, error) {
+	return nil, core.ErrCantGetTrack
+}
+
+func (c *Client) AddTrack(media *core.Media, _ *core.Codec, track *core.Receiver) error {
+	if c.sender == nil {
+		c.sender = core.NewSender(media, track.Codec)
+		c.sender.Handler = func(packet *rtp.Packet) {
+			c.pipe.Write(packet.Payload)
+
+			c.send += len(packet.Payload)
+		}
+	}
+
+	c.sender.HandleRTP(track)
+	return nil
+}
+
+func (c *Client) Start() (err error) {
+	if err = c.Open(); err != nil {
+		return
+	}
+	return
+}
+
+func (c *Client) Stop() (err error) {
+	if c.sender != nil {
+		c.sender.Close()
+	}
+
+	if c.conn != nil {
+		_ = c.Close()
+		return c.conn.Close()
+	}
+
+	return nil
+}
+
+func (c *Client) MarshalJSON() ([]byte, error) {
+	info := &core.Info{
+		Type:   "Command Backchannel PCMA",
+		Medias: c.medias,
+		Send:   c.send,
+	}
+	if c.sender != nil {
+		info.Senders = []*core.Sender{c.sender}
+	}
+	return json.Marshal(info)
+}