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
|
package report
import (
"math/rand"
"sync"
"time"
"github.com/pion/rtcp"
"github.com/pion/rtp"
)
type receiverStream struct {
ssrc uint32
receiverSSRC uint32
clockRate float64
m sync.Mutex
size uint16
packets []uint64
started bool
seqnumCycles uint16
lastSeqnum uint16
lastReportSeqnum uint16
lastRTPTimeRTP uint32
lastRTPTimeTime time.Time
jitter float64
lastSenderReport uint32
lastSenderReportTime time.Time
totalLost uint32
}
func newReceiverStream(ssrc uint32, clockRate uint32) *receiverStream {
receiverSSRC := rand.Uint32() // #nosec
return &receiverStream{
ssrc: ssrc,
receiverSSRC: receiverSSRC,
clockRate: float64(clockRate),
size: 128,
packets: make([]uint64, 128),
}
}
func (stream *receiverStream) processRTP(now time.Time, pkt *rtp.Packet) {
stream.m.Lock()
defer stream.m.Unlock()
if !stream.started { // first frame
stream.started = true
stream.setReceived(pkt.SequenceNumber)
stream.lastSeqnum = pkt.SequenceNumber
stream.lastReportSeqnum = pkt.SequenceNumber - 1
stream.lastRTPTimeRTP = pkt.Timestamp
stream.lastRTPTimeTime = now
} else { // following frames
stream.setReceived(pkt.SequenceNumber)
diff := int32(pkt.SequenceNumber) - int32(stream.lastSeqnum)
if diff > 0 || diff < -0x0FFF {
// overflow
if diff < -0x0FFF {
stream.seqnumCycles++
}
// set missing packets as missing
for i := stream.lastSeqnum + 1; i != pkt.SequenceNumber; i++ {
stream.delReceived(i)
}
stream.lastSeqnum = pkt.SequenceNumber
}
// compute jitter
// https://tools.ietf.org/html/rfc3550#page-39
D := now.Sub(stream.lastRTPTimeTime).Seconds()*stream.clockRate -
(float64(pkt.Timestamp) - float64(stream.lastRTPTimeRTP))
if D < 0 {
D = -D
}
stream.jitter += (D - stream.jitter) / 16
stream.lastRTPTimeRTP = pkt.Timestamp
stream.lastRTPTimeTime = now
}
}
func (stream *receiverStream) setReceived(seq uint16) {
pos := seq % stream.size
stream.packets[pos/64] |= 1 << (pos % 64)
}
func (stream *receiverStream) delReceived(seq uint16) {
pos := seq % stream.size
stream.packets[pos/64] &^= 1 << (pos % 64)
}
func (stream *receiverStream) getReceived(seq uint16) bool {
pos := seq % stream.size
return (stream.packets[pos/64] & (1 << (pos % 64))) != 0
}
func (stream *receiverStream) processSenderReport(now time.Time, sr *rtcp.SenderReport) {
stream.m.Lock()
defer stream.m.Unlock()
stream.lastSenderReport = uint32(sr.NTPTime >> 16)
stream.lastSenderReportTime = now
}
func (stream *receiverStream) generateReport(now time.Time) *rtcp.ReceiverReport {
stream.m.Lock()
defer stream.m.Unlock()
totalSinceReport := stream.lastSeqnum - stream.lastReportSeqnum
totalLostSinceReport := func() uint32 {
if stream.lastSeqnum == stream.lastReportSeqnum {
return 0
}
ret := uint32(0)
for i := stream.lastReportSeqnum + 1; i != stream.lastSeqnum; i++ {
if !stream.getReceived(i) {
ret++
}
}
return ret
}()
stream.totalLost += totalLostSinceReport
// allow up to 24 bits
if totalLostSinceReport > 0xFFFFFF {
totalLostSinceReport = 0xFFFFFF
}
if stream.totalLost > 0xFFFFFF {
stream.totalLost = 0xFFFFFF
}
r := &rtcp.ReceiverReport{
SSRC: stream.receiverSSRC,
Reports: []rtcp.ReceptionReport{
{
SSRC: stream.ssrc,
LastSequenceNumber: uint32(stream.seqnumCycles)<<16 | uint32(stream.lastSeqnum),
LastSenderReport: stream.lastSenderReport,
FractionLost: uint8(float64(totalLostSinceReport*256) / float64(totalSinceReport)),
TotalLost: stream.totalLost,
Delay: func() uint32 {
if stream.lastSenderReportTime.IsZero() {
return 0
}
return uint32(now.Sub(stream.lastSenderReportTime).Seconds() * 65536)
}(),
Jitter: uint32(stream.jitter),
},
},
}
stream.lastReportSeqnum = stream.lastSeqnum
return r
}
|
