Merge remote-tracking branch 'origin/master' into raja_fr

go.mod

@@ -18,7 +18,7 @@ require (
 	github.com/jxskiss/base62 v1.1.0
 	github.com/livekit/mageutil v0.0.0-20230125210925-54e8a70427c1
 	github.com/livekit/mediatransportutil v0.0.0-20230823131232-12f579dc9af0
-	github.com/livekit/protocol v1.6.1
+	github.com/livekit/protocol v1.6.2-0.20230828184341-dfb5162c7c86
 	github.com/livekit/psrpc v0.3.3
 	github.com/mackerelio/go-osstat v0.2.4
 	github.com/magefile/mage v1.15.0

go.sum

@@ -124,8 +124,8 @@ github.com/livekit/mageutil v0.0.0-20230125210925-54e8a70427c1 h1:jm09419p0lqTkD
 github.com/livekit/mageutil v0.0.0-20230125210925-54e8a70427c1/go.mod h1:Rs3MhFwutWhGwmY1VQsygw28z5bWcnEYmS1OG9OxjOQ=
 github.com/livekit/mediatransportutil v0.0.0-20230823131232-12f579dc9af0 h1:cHNvPzn6VHFcsHx8ZC9LwU/4jj22mW3LILrNg/y5A6I=
 github.com/livekit/mediatransportutil v0.0.0-20230823131232-12f579dc9af0/go.mod h1:xirUXW8xnLGmfCwUeAv/nj1VGo1OO1BmgxrYP7jK/14=
-github.com/livekit/protocol v1.6.1 h1:MjRg/UBmynE636In1GD9PbrF2u/C10WwaVIkObsZYtk=
-github.com/livekit/protocol v1.6.1/go.mod h1:/JuO+G/btZ5gNwX2+901L6za3UvVO6DHRXHsv8kkLsU=
+github.com/livekit/protocol v1.6.2-0.20230828184341-dfb5162c7c86 h1:QEzGhfIOmGdRw17xIldbYzb1MTsYuVfXSqz8FTyfjWQ=
+github.com/livekit/protocol v1.6.2-0.20230828184341-dfb5162c7c86/go.mod h1:/JuO+G/btZ5gNwX2+901L6za3UvVO6DHRXHsv8kkLsU=
 github.com/livekit/psrpc v0.3.3 h1:+lltbuN39IdaynXhLLxRShgYqYsRMWeeXKzv60oqyWo=
 github.com/livekit/psrpc v0.3.3/go.mod h1:n6JntEg+zT6Ji8InoyTpV7wusPNwGqqtxmHlkNhDN0U=
 github.com/mackerelio/go-osstat v0.2.4 h1:qxGbdPkFo65PXOb/F/nhDKpF2nGmGaCFDLXoZjJTtUs=

pkg/service/egress.go

@@ -17,6 +17,7 @@ package service
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"reflect"
 
@@ -160,6 +161,10 @@ func (s *EgressService) StartWebEgress(ctx context.Context, req *livekit.WebEgre
 	return ei, err
 }
 
+func (s *EgressService) StartParticipantEgress(ctx context.Context, req *livekit.ParticipantEgressRequest) (*livekit.EgressInfo, error) {
+	return nil, errors.New("under development")
+}
+
 func (s *EgressService) startEgress(ctx context.Context, roomName livekit.RoomName, req *rpc.StartEgressRequest) (*livekit.EgressInfo, error) {
 	if err := EnsureRecordPermission(ctx); err != nil {
 		return nil, twirpAuthError(err)

pkg/sfu/buffer/rtpstats.go

@@ -17,7 +17,6 @@ package buffer
 import (
 	"errors"
 	"fmt"
-	"math"
 	"sync"
 	"time"
 
@@ -44,22 +43,16 @@ const (
 
 // -------------------------------------------------------
 
-type driftResult struct {
-	timeSinceFirst    time.Duration
-	rtpDiffSinceFirst uint64
-	driftSamples      int64
-	driftMs           float64
-	sampleRate        float64
-}
+func RTPDriftToString(r *livekit.RTPDrift) string {
+	if r == nil {
+		return "-"
+	}
 
-func (d driftResult) String() string {
-	return fmt.Sprintf("time: %+v, rtp: %d, driftSamples: %d, driftMs: %.02f, sampleRate: %.02f",
-		d.timeSinceFirst,
-		d.rtpDiffSinceFirst,
-		d.driftSamples,
-		d.driftMs,
-		d.sampleRate,
-	)
+	str := fmt.Sprintf("t: %+v|%+v|%.2fs", r.StartTime.AsTime().Format(time.UnixDate), r.EndTime.AsTime().Format(time.UnixDate), r.Duration)
+	str += fmt.Sprintf(", ts: %d|%d|%d", r.StartTimestamp, r.EndTimestamp, r.RtpClockTicks)
+	str += fmt.Sprintf(", d: %d|%.2fms", r.DriftSamples, r.DriftMs)
+	str += fmt.Sprintf(", cr: %.2f", r.ClockRate)
+	return str
 }
 
 // -------------------------------------------------------
@@ -867,8 +860,10 @@ func (r *RTPStats) SetRtcpSenderReportData(srData *RTCPSenderReportData) {
 			"received anachronous sender report",
 			"currentNTP", srData.NTPTimestamp.Time().String(),
 			"currentRTP", srData.RTPTimestamp,
+			"currentAt", srData.At.String(),
 			"lastNTP", r.srNewest.NTPTimestamp.Time().String(),
 			"lastRTP", r.srNewest.RTPTimestamp,
+			"lastAt", r.srNewest.At.String(),
 		)
 		return
 	}
@@ -891,63 +886,29 @@ func (r *RTPStats) SetRtcpSenderReportData(srData *RTCPSenderReportData) {
 
 	r.maybeAdjustFirstPacketTime(srDataCopy.RTPTimestampExt)
 
-	// monitor and log RTP timestamp anomalies
-	var ntpDiffSinceLast time.Duration
-	var rtpDiffSinceLast uint32
-	var arrivalDiffSinceLast time.Duration
-	var expectedTimeDiffSinceLast float64
-	var isWarped bool
-	if r.srNewest != nil {
-		if srDataCopy.RTPTimestampExt < r.srNewest.RTPTimestampExt {
-			// This can happen when a track is replaced with a null and then restored -
-			// i. e. muting replacing with null and unmute restoring the original track.
-			// Under such a condition reset the sender reports to start from this point.
-			// Resetting will ensure sample rate calculations do not go haywire due to negative time.
-			r.logger.Infow(
-				"received sender report, out-of-order, resetting",
-				"prevTSExt", r.srNewest.RTPTimestampExt,
-				"prevRTP", r.srNewest.RTPTimestamp,
-				"prevNTP", r.srNewest.NTPTimestamp.Time().String(),
-				"currTSExt", srDataCopy.RTPTimestampExt,
-				"currRTP", srDataCopy.RTPTimestamp,
-				"currNTP", srDataCopy.NTPTimestamp.Time().String(),
-			)
-			r.srFirst = &srDataCopy
-			r.srNewest = &srDataCopy
-		}
-
-		ntpDiffSinceLast = srDataCopy.NTPTimestamp.Time().Sub(r.srNewest.NTPTimestamp.Time())
-		rtpDiffSinceLast = srDataCopy.RTPTimestamp - r.srNewest.RTPTimestamp
-		arrivalDiffSinceLast = srDataCopy.At.Sub(r.srNewest.At)
-		expectedTimeDiffSinceLast = float64(rtpDiffSinceLast) / float64(r.params.ClockRate)
-		if math.Abs(expectedTimeDiffSinceLast-ntpDiffSinceLast.Seconds()) > 0.2 {
-			// more than 200 ms away from expected delta
-			isWarped = true
-		}
+	if r.srNewest != nil && srDataCopy.RTPTimestampExt < r.srNewest.RTPTimestampExt {
+		// This can happen when a track is replaced with a null and then restored -
+		// i. e. muting replacing with null and unmute restoring the original track.
+		// Under such a condition reset the sender reports to start from this point.
+		// Resetting will ensure sample rate calculations do not go haywire due to negative time.
+		r.logger.Infow(
+			"received sender report, out-of-order, resetting",
+			"prevTSExt", r.srNewest.RTPTimestampExt,
+			"prevRTP", r.srNewest.RTPTimestamp,
+			"prevNTP", r.srNewest.NTPTimestamp.Time().String(),
+			"prevAt", r.srNewest.At.String(),
+			"currTSExt", srDataCopy.RTPTimestampExt,
+			"currRTP", srDataCopy.RTPTimestamp,
+			"currNTP", srDataCopy.NTPTimestamp.Time().String(),
+			"currentAt", srDataCopy.At.String(),
+		)
+		r.srFirst = nil
 	}
 
 	r.srNewest = &srDataCopy
 	if r.srFirst == nil {
 		r.srFirst = &srDataCopy
 	}
-
-	if isWarped {
-		packetDriftResult, reportDriftResult := r.getDrift()
-		r.logger.Infow(
-			"received sender report, time warp",
-			"ntp", srData.NTPTimestamp.Time().String(),
-			"rtp", srData.RTPTimestamp,
-			"arrival", srData.At.String(),
-			"ntpDiffSinceLast", ntpDiffSinceLast.Seconds(),
-			"rtpDiffSinceLast", int32(rtpDiffSinceLast),
-			"arrivalDiffSinceLast", arrivalDiffSinceLast.Seconds(),
-			"expectedTimeDiffSinceLast", expectedTimeDiffSinceLast,
-			"packetDrift", packetDriftResult.String(),
-			"reportDrift", reportDriftResult.String(),
-			"highestTS", r.timestamp.GetExtendedHighest(),
-			"highestTime", r.highestTime.String(),
-		)
-	}
 }
 
 func (r *RTPStats) GetRtcpSenderReportData() (srFirst *RTCPSenderReportData, srNewest *RTCPSenderReportData) {
@@ -996,6 +957,7 @@ func (r *RTPStats) GetRtcpSenderReport(ssrc uint32, calculatedClockRate uint32)
 
 	timeSinceHighest := now.Sub(r.highestTime)
 	nowRTPExt := r.timestamp.GetExtendedHighest() + uint64(timeSinceHighest.Nanoseconds()*int64(r.params.ClockRate)/1e9)
+	nowRTPExtUsingTime := nowRTPExt
 	nowRTP := uint32(nowRTPExt)
 
 	// It is possible that publisher is pacing at a slower rate.
@@ -1030,30 +992,20 @@ func (r *RTPStats) GetRtcpSenderReport(ssrc uint32, calculatedClockRate uint32)
 			"currTSExt", nowRTPExt,
 			"currRTP", nowRTP,
 			"currNTP", nowNTP.Time().String(),
+			"timeNow", time.Now().String(),
+			"firstTime", r.firstTime.String(),
+			"timeSinceFirst", timeSinceFirst,
+			"highestTime", r.highestTime.String(),
+			"timeSinceHighest", timeSinceHighest,
+			"nowRTPExtUsingTime", nowRTPExtUsingTime,
+			"calculatedClockRate", calculatedClockRate,
+			"nowRTPExtUsingRate", nowRTPExtUsingRate,
 		)
 		ntpDiffSinceLast := nowNTP.Time().Sub(r.srNewest.NTPTimestamp.Time())
 		nowRTPExt = r.srNewest.RTPTimestampExt + uint64(ntpDiffSinceLast.Seconds()*float64(r.params.ClockRate))
 		nowRTP = uint32(nowRTPExt)
 	}
 
-	// monitor and log RTP timestamp anomalies
-	var ntpDiffSinceLast time.Duration
-	var rtpDiffSinceLast uint64
-	var departureDiffSinceLast time.Duration
-	var expectedTimeDiffSinceLast float64
-	var isWarped bool
-	if r.srNewest != nil {
-		ntpDiffSinceLast = nowNTP.Time().Sub(r.srNewest.NTPTimestamp.Time())
-		rtpDiffSinceLast = nowRTPExt - r.srNewest.RTPTimestampExt
-		departureDiffSinceLast = now.Sub(r.srNewest.At)
-
-		expectedTimeDiffSinceLast = float64(rtpDiffSinceLast) / float64(r.params.ClockRate)
-		if math.Abs(expectedTimeDiffSinceLast-ntpDiffSinceLast.Seconds()) > 0.2 {
-			// more than 200 ms away from expected delta
-			isWarped = true
-		}
-	}
-
 	r.srNewest = &RTCPSenderReportData{
 		NTPTimestamp:    nowNTP,
 		RTPTimestamp:    nowRTP,
@@ -1064,27 +1016,6 @@ func (r *RTPStats) GetRtcpSenderReport(ssrc uint32, calculatedClockRate uint32)
 		r.srFirst = r.srNewest
 	}
 
-	if isWarped {
-		packetDriftResult, reportDriftResult := r.getDrift()
-		r.logger.Infow(
-			"sending sender report, time warp",
-			"ntp", nowNTP.Time().String(),
-			"rtp", nowRTP,
-			"departure", now.String(),
-			"ntpDiffSinceLast", ntpDiffSinceLast.Seconds(),
-			"rtpDiffSinceLast", int32(rtpDiffSinceLast),
-			"departureDiffSinceLast", departureDiffSinceLast.Seconds(),
-			"expectedTimeDiffSinceLast", expectedTimeDiffSinceLast,
-			"packetDrift", packetDriftResult.String(),
-			"reportDrift", reportDriftResult.String(),
-			"highestTS", r.timestamp.GetExtendedHighest(),
-			"highestTime", r.highestTime.String(),
-			"calculatedClockRate", calculatedClockRate,
-			"nowRTPExt", nowRTPExt,
-			"nowRTPExtUsingRate", nowRTPExtUsingRate,
-		)
-	}
-
 	return &rtcp.SenderReport{
 		SSRC:        ssrc,
 		NTPTime:     uint64(nowNTP),
@@ -1352,12 +1283,7 @@ func (r *RTPStats) ToString() string {
 	str += ", rtt(ms):"
 	str += fmt.Sprintf("%d|%d", p.RttCurrent, p.RttMax)
 
-	str += ", drift(ms):"
-	str += fmt.Sprintf("%.2f", p.DriftMs)
-
-	str += ", sr(Hz):"
-	str += fmt.Sprintf("%.2f", p.SampleRate)
-
+	str += fmt.Sprintf(", pd: %s, rd: %s", RTPDriftToString(p.PacketDrift), RTPDriftToString(p.ReportDrift))
 	return str
 }
 
@@ -1405,7 +1331,7 @@ func (r *RTPStats) ToProto() *livekit.RTPStats {
 	jitterTime := jitter / float64(r.params.ClockRate) * 1e6
 	maxJitterTime := maxJitter / float64(r.params.ClockRate) * 1e6
 
-	packetDrift, _ := r.getDrift()
+	packetDrift, reportDrift := r.getDrift()
 
 	p := &livekit.RTPStats{
 		StartTime:            timestamppb.New(r.startTime),
@@ -1448,8 +1374,8 @@ func (r *RTPStats) ToProto() *livekit.RTPStats {
 		LastFir:              timestamppb.New(r.lastFir),
 		RttCurrent:           r.rtt,
 		RttMax:               r.maxRtt,
-		DriftMs:              packetDrift.driftMs,
-		SampleRate:           packetDrift.sampleRate,
+		PacketDrift:          packetDrift,
+		ReportDrift:          reportDrift,
 	}
 
 	gapsPresent := false
@@ -1636,22 +1562,42 @@ func (r *RTPStats) updateJitter(rtph *rtp.Header, packetTime time.Time) {
 	r.lastJitterRTP = rtph.Timestamp
 }
 
-func (r *RTPStats) getDrift() (packetDrift driftResult, reportDrift driftResult) {
-	packetDrift.timeSinceFirst = r.highestTime.Sub(r.firstTime)
-	packetDrift.rtpDiffSinceFirst = r.timestamp.GetExtendedHighest() - r.timestamp.GetExtendedStart()
-	packetDrift.driftSamples = int64(packetDrift.rtpDiffSinceFirst - uint64(packetDrift.timeSinceFirst.Nanoseconds()*int64(r.params.ClockRate)/1e9))
-	packetDrift.driftMs = (float64(packetDrift.driftSamples) * 1000) / float64(r.params.ClockRate)
-	if packetDrift.timeSinceFirst.Seconds() != 0 {
-		packetDrift.sampleRate = float64(packetDrift.rtpDiffSinceFirst) / packetDrift.timeSinceFirst.Seconds()
+func (r *RTPStats) getDrift() (packetDrift *livekit.RTPDrift, reportDrift *livekit.RTPDrift) {
+	if !r.firstTime.IsZero() {
+		elapsed := r.highestTime.Sub(r.firstTime)
+		rtpClockTicks := r.timestamp.GetExtendedHighest() - r.timestamp.GetExtendedStart()
+		driftSamples := int64(rtpClockTicks - uint64(elapsed.Nanoseconds()*int64(r.params.ClockRate)/1e9))
+		if elapsed.Seconds() > 0.0 {
+			packetDrift = &livekit.RTPDrift{
+				StartTime:      timestamppb.New(r.firstTime),
+				EndTime:        timestamppb.New(r.highestTime),
+				Duration:       elapsed.Seconds(),
+				StartTimestamp: r.timestamp.GetExtendedStart(),
+				EndTimestamp:   r.timestamp.GetExtendedHighest(),
+				RtpClockTicks:  rtpClockTicks,
+				DriftSamples:   driftSamples,
+				DriftMs:        (float64(driftSamples) * 1000) / float64(r.params.ClockRate),
+				ClockRate:      float64(rtpClockTicks) / elapsed.Seconds(),
+			}
+		}
 	}
 
 	if r.srFirst != nil && r.srNewest != nil && r.srFirst.RTPTimestamp != r.srNewest.RTPTimestamp {
-		reportDrift.timeSinceFirst = r.srNewest.NTPTimestamp.Time().Sub(r.srFirst.NTPTimestamp.Time())
-		reportDrift.rtpDiffSinceFirst = r.srNewest.RTPTimestampExt - r.srFirst.RTPTimestampExt
-		reportDrift.driftSamples = int64(reportDrift.rtpDiffSinceFirst - uint64(reportDrift.timeSinceFirst.Nanoseconds()*int64(r.params.ClockRate)/1e9))
-		reportDrift.driftMs = (float64(reportDrift.driftSamples) * 1000) / float64(r.params.ClockRate)
-		if reportDrift.timeSinceFirst.Seconds() != 0 {
-			reportDrift.sampleRate = float64(reportDrift.rtpDiffSinceFirst) / reportDrift.timeSinceFirst.Seconds()
+		elapsed := r.srNewest.NTPTimestamp.Time().Sub(r.srFirst.NTPTimestamp.Time())
+		rtpClockTicks := r.srNewest.RTPTimestampExt - r.srFirst.RTPTimestampExt
+		driftSamples := int64(rtpClockTicks - uint64(elapsed.Nanoseconds()*int64(r.params.ClockRate)/1e9))
+		if elapsed.Seconds() > 0.0 {
+			reportDrift = &livekit.RTPDrift{
+				StartTime:      timestamppb.New(r.srFirst.NTPTimestamp.Time()),
+				EndTime:        timestamppb.New(r.srNewest.NTPTimestamp.Time()),
+				Duration:       elapsed.Seconds(),
+				StartTimestamp: r.timestamp.GetExtendedStart(),
+				EndTimestamp:   r.timestamp.GetExtendedHighest(),
+				RtpClockTicks:  rtpClockTicks,
+				DriftSamples:   driftSamples,
+				DriftMs:        (float64(driftSamples) * 1000) / float64(r.params.ClockRate),
+				ClockRate:      float64(rtpClockTicks) / elapsed.Seconds(),
+			}
 		}
 	}
 	return
@@ -1754,8 +1700,6 @@ func AggregateRTPStats(statsList []*livekit.RTPStats) *livekit.RTPStats {
 	lastFir := time.Time{}
 	rtt := uint32(0)
 	maxRtt := uint32(0)
-	driftMs := float64(0.0)
-	sampleRate := float64(0.0)
 
 	for _, stats := range statsList {
 		if startTime.IsZero() || startTime.After(stats.StartTime.AsTime()) {
@@ -1822,9 +1766,6 @@ func AggregateRTPStats(statsList []*livekit.RTPStats) *livekit.RTPStats {
 		if stats.RttMax > maxRtt {
 			maxRtt = stats.RttMax
 		}
-
-		driftMs += stats.DriftMs
-		sampleRate += stats.SampleRate
 	}
 
 	if endTime.IsZero() {
@@ -1887,8 +1828,7 @@ func AggregateRTPStats(statsList []*livekit.RTPStats) *livekit.RTPStats {
 		LastFir:              timestamppb.New(lastFir),
 		RttCurrent:           rtt / uint32(len(statsList)),
 		RttMax:               maxRtt,
-		DriftMs:              driftMs / float64(len(statsList)),
-		SampleRate:           sampleRate / float64(len(statsList)),
+		// no aggregation for drift calculations
 	}
 }
 

pkg/sfu/downtrack.go

@@ -1136,7 +1136,7 @@ func (d *DownTrack) ProvisionalAllocateReset() {
 	d.forwarder.ProvisionalAllocateReset()
 }
 
-func (d *DownTrack) ProvisionalAllocate(availableChannelCapacity int64, layers buffer.VideoLayer, allowPause bool, allowOvershoot bool) int64 {
+func (d *DownTrack) ProvisionalAllocate(availableChannelCapacity int64, layers buffer.VideoLayer, allowPause bool, allowOvershoot bool) (bool, int64) {
 	return d.forwarder.ProvisionalAllocate(availableChannelCapacity, layers, allowPause, allowOvershoot)
 }
 

pkg/sfu/forwarder.go

@@ -728,7 +728,7 @@ func (f *Forwarder) ProvisionalAllocateReset() {
 	f.provisional.allocatedLayer = buffer.InvalidLayer
 }
 
-func (f *Forwarder) ProvisionalAllocate(availableChannelCapacity int64, layer buffer.VideoLayer, allowPause bool, allowOvershoot bool) int64 {
+func (f *Forwarder) ProvisionalAllocate(availableChannelCapacity int64, layer buffer.VideoLayer, allowPause bool, allowOvershoot bool) (bool, int64) {
 	f.lock.Lock()
 	defer f.lock.Unlock()
 
@@ -737,12 +737,12 @@ func (f *Forwarder) ProvisionalAllocate(availableChannelCapacity int64, layer bu
 		f.provisional.maxSeenLayer.Spatial == buffer.InvalidLayerSpatial ||
 		!f.provisional.maxLayer.IsValid() ||
 		((!allowOvershoot || !f.vls.IsOvershootOkay()) && layer.GreaterThan(f.provisional.maxLayer)) {
-		return 0
+		return false, 0
 	}
 
 	requiredBitrate := f.provisional.Bitrates[layer.Spatial][layer.Temporal]
 	if requiredBitrate == 0 {
-		return 0
+		return false, 0
 	}
 
 	alreadyAllocatedBitrate := int64(0)
@@ -753,7 +753,7 @@ func (f *Forwarder) ProvisionalAllocate(availableChannelCapacity int64, layer bu
 	// a layer under maximum fits, take it
 	if !layer.GreaterThan(f.provisional.maxLayer) && requiredBitrate <= (availableChannelCapacity+alreadyAllocatedBitrate) {
 		f.provisional.allocatedLayer = layer
-		return requiredBitrate - alreadyAllocatedBitrate
+		return true, requiredBitrate - alreadyAllocatedBitrate
 	}
 
 	//
@@ -766,10 +766,10 @@ func (f *Forwarder) ProvisionalAllocate(availableChannelCapacity int64, layer bu
 	//
 	if !allowPause && (!f.provisional.allocatedLayer.IsValid() || !layer.GreaterThan(f.provisional.allocatedLayer)) {
 		f.provisional.allocatedLayer = layer
-		return requiredBitrate - alreadyAllocatedBitrate
+		return true, requiredBitrate - alreadyAllocatedBitrate
 	}
 
-	return 0
+	return false, 0
 }
 
 func (f *Forwarder) ProvisionalAllocateGetCooperativeTransition(allowOvershoot bool) VideoTransition {

pkg/sfu/forwarder_test.go

@@ -400,20 +400,25 @@ func TestForwarderProvisionalAllocate(t *testing.T) {
 
 	f.ProvisionalAllocatePrepare(nil, bitrates)
 
-	usedBitrate := f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 0, Temporal: 0}, true, false)
+	isCandidate, usedBitrate := f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 0, Temporal: 0}, true, false)
+	require.True(t, isCandidate)
 	require.Equal(t, bitrates[0][0], usedBitrate)
 
-	usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 2, Temporal: 3}, true, false)
+	isCandidate, usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 2, Temporal: 3}, true, false)
+	require.True(t, isCandidate)
 	require.Equal(t, bitrates[2][3]-bitrates[0][0], usedBitrate)
 
-	usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 0, Temporal: 3}, true, false)
+	isCandidate, usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 0, Temporal: 3}, true, false)
+	require.True(t, isCandidate)
 	require.Equal(t, bitrates[0][3]-bitrates[2][3], usedBitrate)
 
-	usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 1, Temporal: 2}, true, false)
+	isCandidate, usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 1, Temporal: 2}, true, false)
+	require.True(t, isCandidate)
 	require.Equal(t, bitrates[1][2]-bitrates[0][3], usedBitrate)
 
 	// available not enough to reach (2, 2), allocating at (2, 2) should not succeed
-	usedBitrate = f.ProvisionalAllocate(bitrates[2][2]-bitrates[1][2]-1, buffer.VideoLayer{Spatial: 2, Temporal: 2}, true, false)
+	isCandidate, usedBitrate = f.ProvisionalAllocate(bitrates[2][2]-bitrates[1][2]-1, buffer.VideoLayer{Spatial: 2, Temporal: 2}, true, false)
+	require.False(t, isCandidate)
 	require.Equal(t, int64(0), usedBitrate)
 
 	// committing should set target to (1, 2)
@@ -440,7 +445,8 @@ func TestForwarderProvisionalAllocate(t *testing.T) {
 	// when nothing fits and pausing disallowed, should allocate (0, 0)
 	f.vls.SetTarget(buffer.InvalidLayer)
 	f.ProvisionalAllocatePrepare(nil, bitrates)
-	usedBitrate = f.ProvisionalAllocate(0, buffer.VideoLayer{Spatial: 0, Temporal: 0}, false, false)
+	isCandidate, usedBitrate = f.ProvisionalAllocate(0, buffer.VideoLayer{Spatial: 0, Temporal: 0}, false, false)
+	require.True(t, isCandidate)
 	require.Equal(t, int64(1), usedBitrate)
 
 	// committing should set target to (0, 0)
@@ -477,15 +483,18 @@ func TestForwarderProvisionalAllocate(t *testing.T) {
 
 	f.ProvisionalAllocatePrepare(nil, bitrates)
 
-	usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 0, Temporal: 0}, false, true)
+	isCandidate, usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 0, Temporal: 0}, false, true)
+	require.False(t, isCandidate)
 	require.Equal(t, int64(0), usedBitrate)
 
 	// overshoot should succeed
-	usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 2, Temporal: 3}, false, true)
+	isCandidate, usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 2, Temporal: 3}, false, true)
+	require.True(t, isCandidate)
 	require.Equal(t, bitrates[2][3], usedBitrate)
 
 	// overshoot should succeed - this should win as this is lesser overshoot
-	usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 1, Temporal: 3}, false, true)
+	isCandidate, usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 1, Temporal: 3}, false, true)
+	require.True(t, isCandidate)
 	require.Equal(t, bitrates[1][3]-bitrates[2][3], usedBitrate)
 
 	// committing should set target to (1, 3)
@@ -524,15 +533,18 @@ func TestForwarderProvisionalAllocate(t *testing.T) {
 	f.ProvisionalAllocatePrepare(nil, bitrates)
 
 	// all the provisional allocations should not succeed because the feed is dry
-	usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 0, Temporal: 0}, false, true)
+	isCandidate, usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 0, Temporal: 0}, false, true)
+	require.False(t, isCandidate)
 	require.Equal(t, int64(0), usedBitrate)
 
 	// overshoot should not succeed
-	usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 2, Temporal: 3}, false, true)
+	isCandidate, usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 2, Temporal: 3}, false, true)
+	require.False(t, isCandidate)
 	require.Equal(t, int64(0), usedBitrate)
 
 	// overshoot should not succeed
-	usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 1, Temporal: 3}, false, true)
+	isCandidate, usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 1, Temporal: 3}, false, true)
+	require.False(t, isCandidate)
 	require.Equal(t, int64(0), usedBitrate)
 
 	// committing should set target to (0, 2), i. e. leave it at current for opportunistic forwarding
@@ -562,15 +574,18 @@ func TestForwarderProvisionalAllocate(t *testing.T) {
 	f.ProvisionalAllocatePrepare(nil, bitrates)
 
 	// all the provisional allocations below should not succeed because the feed is dry
-	usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 0, Temporal: 0}, false, true)
+	isCandidate, usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 0, Temporal: 0}, false, true)
+	require.False(t, isCandidate)
 	require.Equal(t, int64(0), usedBitrate)
 
 	// overshoot should not succeed
-	usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 2, Temporal: 3}, false, true)
+	isCandidate, usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 2, Temporal: 3}, false, true)
+	require.False(t, isCandidate)
 	require.Equal(t, int64(0), usedBitrate)
 
 	// overshoot should not succeed
-	usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 1, Temporal: 3}, false, true)
+	isCandidate, usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 1, Temporal: 3}, false, true)
+	require.False(t, isCandidate)
 	require.Equal(t, int64(0), usedBitrate)
 
 	expectedResult = VideoAllocation{
@@ -604,10 +619,12 @@ func TestForwarderProvisionalAllocateMute(t *testing.T) {
 	f.Mute(true)
 	f.ProvisionalAllocatePrepare(nil, bitrates)
 
-	usedBitrate := f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 0, Temporal: 0}, true, false)
+	isCandidate, usedBitrate := f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 0, Temporal: 0}, true, false)
+	require.False(t, isCandidate)
 	require.Equal(t, int64(0), usedBitrate)
 
-	usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 1, Temporal: 2}, true, true)
+	isCandidate, usedBitrate = f.ProvisionalAllocate(bitrates[2][3], buffer.VideoLayer{Spatial: 1, Temporal: 2}, true, true)
+	require.False(t, isCandidate)
 	require.Equal(t, int64(0), usedBitrate)
 
 	// committing should set target to buffer.InvalidLayer as track is muted

pkg/sfu/streamallocator/streamallocator.go

@@ -883,9 +883,15 @@ func (s *StreamAllocator) allocateTrack(track *Track) {
 		return
 	}
 
-	// this track is currently not streaming and needs bits to start.
-	// first try an allocation using available headroom
-	availableChannelCapacity := s.getAvailableHeadroom(false)
+	// already streaming at some layer and transition is not requesting any change, i. e. BandwidthDelta == 0
+	if transition.From.IsValid() && transition.BandwidthDelta == 0 {
+		return
+	}
+
+	// this track is currently not streaming and needs bits to start OR streaming at some layer and wants more bits.
+	// NOTE: With co-operative transition, tracks should not be asking for more if already streaming, but handle that case any way.
+	// first try an allocation using available headroom, current consumption of this track is discounted to calculate headroom.
+	availableChannelCapacity := s.getAvailableHeadroomWithoutTracks(false, []*Track{track})
 	if availableChannelCapacity > 0 {
 		track.ProvisionalAllocateReset() // to reset allocation from co-operative transition above and try fresh
 
@@ -899,21 +905,30 @@ func (s *StreamAllocator) allocateTrack(track *Track) {
 					Temporal: temporal,
 				}
 
-				usedChannelCapacity := track.ProvisionalAllocate(availableChannelCapacity, layer, s.allowPause, FlagAllowOvershootWhileDeficient)
+				isCandidate, usedChannelCapacity := track.ProvisionalAllocate(
+					availableChannelCapacity,
+					layer,
+					s.allowPause,
+					FlagAllowOvershootWhileDeficient,
+				)
 				if availableChannelCapacity < usedChannelCapacity {
 					break alloc_loop
 				}
 
-				bestLayer = layer
+				if isCandidate {
+					bestLayer = layer
+				}
 			}
 		}
 
 		if bestLayer.IsValid() {
-			// found layer that can fit in available headroom
-			update := NewStreamStateUpdate()
-			allocation := track.ProvisionalAllocateCommit()
-			updateStreamStateChange(track, allocation, update)
-			s.maybeSendUpdate(update)
+			if bestLayer.GreaterThan(transition.From) {
+				// found layer that can fit in available headroom, take it if it is better than existing
+				update := NewStreamStateUpdate()
+				allocation := track.ProvisionalAllocateCommit()
+				updateStreamStateChange(track, allocation, update)
+				s.maybeSendUpdate(update)
+			}
 
 			s.adjustState()
 			return
@@ -923,11 +938,6 @@ func (s *StreamAllocator) allocateTrack(track *Track) {
 		transition = track.ProvisionalAllocateGetCooperativeTransition(FlagAllowOvershootWhileDeficient) // get transition again to reset above allocation attempt using available headroom
 	}
 
-	// track is currently streaming at minimum
-	if transition.BandwidthDelta == 0 {
-		return
-	}
-
 	// if there is not enough headroom, try to redistribute starting with tracks that are closest to their desired.
 	bandwidthAcquired := int64(0)
 	var contributingTracks []*Track
@@ -1018,17 +1028,31 @@ func (s *StreamAllocator) maybeBoostDeficientTracks() {
 
 	update := NewStreamStateUpdate()
 
-	for _, track := range s.getMaxDistanceSortedDeficient() {
-		allocation, boosted := track.AllocateNextHigher(availableChannelCapacity, FlagAllowOvershootInCatchup)
-		if !boosted {
-			continue
+	sortedTracks := s.getMaxDistanceSortedDeficient()
+boost_loop:
+	for {
+		for idx, track := range sortedTracks {
+			allocation, boosted := track.AllocateNextHigher(availableChannelCapacity, FlagAllowOvershootInCatchup)
+			if !boosted {
+				if idx == len(sortedTracks)-1 {
+					// all tracks tried
+					break boost_loop
+				}
+				continue
+			}
+
+			updateStreamStateChange(track, allocation, update)
+
+			availableChannelCapacity -= allocation.BandwidthDelta
+			if availableChannelCapacity <= 0 {
+				break boost_loop
+			}
+
+			break // sort again below as the track that was just boosted could still be farthest from its desired
 		}
-
-		updateStreamStateChange(track, allocation, update)
-
-		availableChannelCapacity -= allocation.BandwidthDelta
-		if availableChannelCapacity <= 0 {
-			break
+		sortedTracks = s.getMaxDistanceSortedDeficient()
+		if len(sortedTracks) == 0 {
+			break // nothing available to boost
 		}
 	}
 
@@ -1103,7 +1127,7 @@ func (s *StreamAllocator) allocateAllTracks() {
 				}
 
 				for _, track := range sorted {
-					usedChannelCapacity := track.ProvisionalAllocate(availableChannelCapacity, layer, s.allowPause, FlagAllowOvershootWhileDeficient)
+					_, usedChannelCapacity := track.ProvisionalAllocate(availableChannelCapacity, layer, s.allowPause, FlagAllowOvershootWhileDeficient)
 					availableChannelCapacity -= usedChannelCapacity
 					if availableChannelCapacity < 0 {
 						availableChannelCapacity = 0
@@ -1174,10 +1198,32 @@ func (s *StreamAllocator) getExpectedBandwidthUsage() int64 {
 	return expected
 }
 
+func (s *StreamAllocator) getExpectedBandwidthUsageWithoutTracks(filteredTracks []*Track) int64 {
+	expected := int64(0)
+	for _, track := range s.getTracks() {
+		filtered := false
+		for _, ft := range filteredTracks {
+			if ft == track {
+				filtered = true
+				break
+			}
+		}
+		if !filtered {
+			expected += track.BandwidthRequested()
+		}
+	}
+
+	return expected
+}
+
 func (s *StreamAllocator) getAvailableHeadroom(allowOverride bool) int64 {
 	return s.getAvailableChannelCapacity(allowOverride) - s.getExpectedBandwidthUsage()
 }
 
+func (s *StreamAllocator) getAvailableHeadroomWithoutTracks(allowOverride bool, filteredTracks []*Track) int64 {
+	return s.getAvailableChannelCapacity(allowOverride) - s.getExpectedBandwidthUsageWithoutTracks(filteredTracks)
+}
+
 func (s *StreamAllocator) getNackDelta() (uint32, uint32) {
 	aggPacketDelta := uint32(0)
 	aggRepeatedNackDelta := uint32(0)

pkg/sfu/streamallocator/track.go

@@ -164,7 +164,7 @@ func (t *Track) ProvisionalAllocateReset() {
 	t.downTrack.ProvisionalAllocateReset()
 }
 
-func (t *Track) ProvisionalAllocate(availableChannelCapacity int64, layer buffer.VideoLayer, allowPause bool, allowOvershoot bool) int64 {
+func (t *Track) ProvisionalAllocate(availableChannelCapacity int64, layer buffer.VideoLayer, allowPause bool, allowOvershoot bool) (bool, int64) {
 	return t.downTrack.ProvisionalAllocate(availableChannelCapacity, layer, allowPause, allowOvershoot)
 }