install go2rtc on bob

installs_on_host/go2rtc/pkg/dvrip/backchannel.go

@@ -0,0 +1,79 @@
+package dvrip
+
+import (
+	"encoding/binary"
+	"time"
+
+	"github.com/AlexxIT/go2rtc/pkg/core"
+	"github.com/pion/rtp"
+)
+
+type Backchannel struct {
+	core.Connection
+	client *Client
+}
+
+func (c *Backchannel) GetTrack(media *core.Media, codec *core.Codec) (*core.Receiver, error) {
+	return nil, core.ErrCantGetTrack
+}
+
+func (c *Backchannel) Start() error {
+	if err := c.client.conn.SetReadDeadline(time.Time{}); err != nil {
+		return err
+	}
+
+	b := make([]byte, 4096)
+	for {
+		if _, err := c.client.rd.Read(b); err != nil {
+			return err
+		}
+	}
+}
+
+func (c *Backchannel) AddTrack(media *core.Media, _ *core.Codec, track *core.Receiver) error {
+	if err := c.client.Talk(); err != nil {
+		return err
+	}
+
+	const PacketSize = 320
+
+	buf := make([]byte, 8+PacketSize)
+	binary.BigEndian.PutUint32(buf, 0x1FA)
+
+	switch track.Codec.Name {
+	case core.CodecPCMU:
+		buf[4] = 10
+	case core.CodecPCMA:
+		buf[4] = 14
+	}
+
+	//for i, rate := range sampleRates {
+	//	if rate == track.Codec.ClockRate {
+	//		buf[5] = byte(i) + 1
+	//		break
+	//	}
+	//}
+	buf[5] = 2 // ClockRate=8000
+
+	binary.LittleEndian.PutUint16(buf[6:], PacketSize)
+
+	var payload []byte
+
+	sender := core.NewSender(media, track.Codec)
+	sender.Handler = func(packet *rtp.Packet) {
+		payload = append(payload, packet.Payload...)
+
+		for len(payload) >= PacketSize {
+			buf = append(buf[:8], payload[:PacketSize]...)
+			if n, err := c.client.WriteCmd(OPTalkData, buf); err != nil {
+				c.Send += n
+			}
+
+			payload = payload[PacketSize:]
+		}
+	}
+
+	sender.HandleRTP(track)
+	c.Senders = append(c.Senders, sender)
+	return nil
+}