1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
|
// +build !js
package webrtc
import (
"fmt"
"sync/atomic"
"github.com/pion/rtp"
)
// RTPTransceiver represents a combination of an RTPSender and an RTPReceiver that share a common mid.
type RTPTransceiver struct {
mid atomic.Value // string
sender atomic.Value // *RTPSender
receiver atomic.Value // *RTPReceiver
direction atomic.Value // RTPTransceiverDirection
stopped bool
kind RTPCodecType
}
// Sender returns the RTPTransceiver's RTPSender if it has one
func (t *RTPTransceiver) Sender() *RTPSender {
if v := t.sender.Load(); v != nil {
return v.(*RTPSender)
}
return nil
}
// SetSender sets the RTPSender and Track to current transceiver
func (t *RTPTransceiver) SetSender(s *RTPSender, track TrackLocal) error {
t.setSender(s)
return t.setSendingTrack(track)
}
func (t *RTPTransceiver) setSender(s *RTPSender) {
t.sender.Store(s)
}
// Receiver returns the RTPTransceiver's RTPReceiver if it has one
func (t *RTPTransceiver) Receiver() *RTPReceiver {
if v := t.receiver.Load(); v != nil {
return v.(*RTPReceiver)
}
return nil
}
// setMid sets the RTPTransceiver's mid. If it was already set, will return an error.
func (t *RTPTransceiver) setMid(mid string) error {
if currentMid := t.Mid(); currentMid != "" {
return fmt.Errorf("%w: %s to %s", errRTPTransceiverCannotChangeMid, currentMid, mid)
}
t.mid.Store(mid)
return nil
}
// Mid gets the Transceiver's mid value. When not already set, this value will be set in CreateOffer or CreateAnswer.
func (t *RTPTransceiver) Mid() string {
if v := t.mid.Load(); v != nil {
return v.(string)
}
return ""
}
// Kind returns RTPTransceiver's kind.
func (t *RTPTransceiver) Kind() RTPCodecType {
return t.kind
}
// Direction returns the RTPTransceiver's current direction
func (t *RTPTransceiver) Direction() RTPTransceiverDirection {
return t.direction.Load().(RTPTransceiverDirection)
}
// Stop irreversibly stops the RTPTransceiver
func (t *RTPTransceiver) Stop() error {
if t.Sender() != nil {
if err := t.Sender().Stop(); err != nil {
return err
}
}
if t.Receiver() != nil {
if err := t.Receiver().Stop(); err != nil {
return err
}
}
t.setDirection(RTPTransceiverDirectionInactive)
return nil
}
func (t *RTPTransceiver) setReceiver(r *RTPReceiver) {
t.receiver.Store(r)
}
func (t *RTPTransceiver) setDirection(d RTPTransceiverDirection) {
t.direction.Store(d)
}
func (t *RTPTransceiver) setSendingTrack(track TrackLocal) error {
if err := t.Sender().ReplaceTrack(track); err != nil {
return err
}
if track == nil {
t.setSender(nil)
}
switch {
case track != nil && t.Direction() == RTPTransceiverDirectionRecvonly:
t.setDirection(RTPTransceiverDirectionSendrecv)
case track != nil && t.Direction() == RTPTransceiverDirectionInactive:
t.setDirection(RTPTransceiverDirectionSendonly)
case track == nil && t.Direction() == RTPTransceiverDirectionSendrecv:
t.setDirection(RTPTransceiverDirectionRecvonly)
case track == nil && t.Direction() == RTPTransceiverDirectionSendonly:
t.setDirection(RTPTransceiverDirectionInactive)
default:
return errRTPTransceiverSetSendingInvalidState
}
return nil
}
func findByMid(mid string, localTransceivers []*RTPTransceiver) (*RTPTransceiver, []*RTPTransceiver) {
for i, t := range localTransceivers {
if t.Mid() == mid {
return t, append(localTransceivers[:i], localTransceivers[i+1:]...)
}
}
return nil, localTransceivers
}
// Given a direction+type pluck a transceiver from the passed list
// if no entry satisfies the requested type+direction return a inactive Transceiver
func satisfyTypeAndDirection(remoteKind RTPCodecType, remoteDirection RTPTransceiverDirection, localTransceivers []*RTPTransceiver) (*RTPTransceiver, []*RTPTransceiver) {
// Get direction order from most preferred to least
getPreferredDirections := func() []RTPTransceiverDirection {
switch remoteDirection {
case RTPTransceiverDirectionSendrecv:
return []RTPTransceiverDirection{RTPTransceiverDirectionRecvonly, RTPTransceiverDirectionSendrecv}
case RTPTransceiverDirectionSendonly:
return []RTPTransceiverDirection{RTPTransceiverDirectionRecvonly}
case RTPTransceiverDirectionRecvonly:
return []RTPTransceiverDirection{RTPTransceiverDirectionSendonly, RTPTransceiverDirectionSendrecv}
default:
return []RTPTransceiverDirection{}
}
}
for _, possibleDirection := range getPreferredDirections() {
for i := range localTransceivers {
t := localTransceivers[i]
if t.Mid() == "" && t.kind == remoteKind && possibleDirection == t.Direction() {
return t, append(localTransceivers[:i], localTransceivers[i+1:]...)
}
}
}
return nil, localTransceivers
}
// handleUnknownRTPPacket consumes a single RTP Packet and returns information that is helpful
// for demuxing and handling an unknown SSRC (usually for Simulcast)
func handleUnknownRTPPacket(buf []byte, midExtensionID, streamIDExtensionID uint8) (mid, rid string, payloadType PayloadType, err error) {
rp := &rtp.Packet{}
if err = rp.Unmarshal(buf); err != nil {
return
}
if !rp.Header.Extension {
return
}
payloadType = PayloadType(rp.PayloadType)
if payload := rp.GetExtension(midExtensionID); payload != nil {
mid = string(payload)
}
if payload := rp.GetExtension(streamIDExtensionID); payload != nil {
rid = string(payload)
}
return
}
|
