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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, pktHeader *rtp.Header) {
stream.m.Lock()
defer stream.m.Unlock()
if !stream.started { // first frame
stream.started = true
stream.setReceived(pktHeader.SequenceNumber)
stream.lastSeqnum = pktHeader.SequenceNumber
stream.lastReportSeqnum = pktHeader.SequenceNumber - 1
stream.lastRTPTimeRTP = pktHeader.Timestamp
stream.lastRTPTimeTime = now
} else { // following frames
stream.setReceived(pktHeader.SequenceNumber)
diff := int32(pktHeader.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 != pktHeader.SequenceNumber; i++ {
stream.delReceived(i)
}
stream.lastSeqnum = pktHeader.SequenceNumber
}
// compute jitter
// https://tools.ietf.org/html/rfc3550#page-39
D := now.Sub(stream.lastRTPTimeTime).Seconds()*stream.clockRate -
(float64(pktHeader.Timestamp) - float64(stream.lastRTPTimeRTP))
if D < 0 {
D = -D
}
stream.jitter += (D - stream.jitter) / 16
stream.lastRTPTimeRTP = pktHeader.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
}
|
