From 017ed1333842316935abe945a06e40288d8cce7a Mon Sep 17 00:00:00 2001
From: Raja Subramanian <raja.gobi@tutanota.com>
Date: Wed, 12 Jan 2022 23:19:56 +0530
Subject: [PATCH] Prevent multiple resume notifications on track (#334)

* Prevent multiple resume notifications on track

When returning previous allocation as is, reset change to none.
Ideally, would like to have change as a separate return and not in last
allocation. But, also prefer to have last allocation state. For now,
resetting change.

* log bandwidth estimate only on decrease
---
 pkg/sfu/forwarder.go       | 10 ++++++++++
 pkg/sfu/forwarder_test.go  |  2 +-
 pkg/sfu/streamallocator.go |  5 ++++-
 3 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/pkg/sfu/forwarder.go b/pkg/sfu/forwarder.go
index 39538acb1..e2d283384 100644
--- a/pkg/sfu/forwarder.go
+++ b/pkg/sfu/forwarder.go
@@ -406,6 +406,10 @@ func (f *Forwarder) Allocate(availableChannelCapacity int64, allowPause bool, br
 					// when pause is disallowed, pick the lowest available
 					targetLayers.spatial = int32(math.Min(float64(f.maxLayers.spatial), float64(f.availableLayers[0])))
 					targetLayers.temporal = int32(math.Min(0, float64(f.maxLayers.temporal)))
+
+					if f.targetLayers == InvalidLayers {
+						change = VideoStreamingChangeResuming
+					}
 				} else {
 					// disable forwarding as it is not known how big this stream is
 					// and if it will fit in the available channel capacity
@@ -817,6 +821,7 @@ func (f *Forwarder) FinalizeAllocate(brs Bitrates) VideoAllocation {
 	defer f.lock.Unlock()
 
 	if f.lastAllocation.state != VideoAllocationStateAwaitingMeasurement {
+		f.lastAllocation.change = VideoStreamingChangeNone
 		return f.lastAllocation
 	}
 
@@ -886,22 +891,26 @@ func (f *Forwarder) AllocateNextHigher(brs Bitrates) (VideoAllocation, bool) {
 	defer f.lock.Unlock()
 
 	if f.kind == webrtc.RTPCodecTypeAudio {
+		f.lastAllocation.change = VideoStreamingChangeNone
 		return f.lastAllocation, false
 	}
 
 	// if not deficient, nothing to do
 	if f.lastAllocation.state != VideoAllocationStateDeficient {
+		f.lastAllocation.change = VideoStreamingChangeNone
 		return f.lastAllocation, false
 	}
 
 	// if targets are still pending, don't increase
 	if f.targetLayers != InvalidLayers && f.targetLayers != f.currentLayers {
+		f.lastAllocation.change = VideoStreamingChangeNone
 		return f.lastAllocation, false
 	}
 
 	optimalBandwidthNeeded := f.getOptimalBandwidthNeeded(brs)
 	if optimalBandwidthNeeded == 0 {
 		// either feed is dry or awaiting measurement, don't hunt for higher
+		f.lastAllocation.change = VideoStreamingChangeNone
 		return f.lastAllocation, false
 	}
 
@@ -968,6 +977,7 @@ func (f *Forwarder) AllocateNextHigher(brs Bitrates) (VideoAllocation, bool) {
 		}
 	}
 
+	f.lastAllocation.change = VideoStreamingChangeNone
 	return f.lastAllocation, false
 }
 
diff --git a/pkg/sfu/forwarder_test.go b/pkg/sfu/forwarder_test.go
index 5d497bcd7..1b5751376 100644
--- a/pkg/sfu/forwarder_test.go
+++ b/pkg/sfu/forwarder_test.go
@@ -227,7 +227,7 @@ func TestForwarderAllocate(t *testing.T) {
 	}
 	expectedResult = VideoAllocation{
 		state:              VideoAllocationStateAwaitingMeasurement,
-		change:             VideoStreamingChangeNone,
+		change:             VideoStreamingChangeResuming,
 		bandwidthRequested: 0,
 		bandwidthDelta:     0,
 		availableLayers:    []uint16{0},
diff --git a/pkg/sfu/streamallocator.go b/pkg/sfu/streamallocator.go
index ff4c03c53..58a79a265 100644
--- a/pkg/sfu/streamallocator.go
+++ b/pkg/sfu/streamallocator.go
@@ -687,10 +687,13 @@ func (s *StreamAllocator) maybeCommitEstimate() (isDecreasing bool) {
 		s.lastEstimateDecreaseTime = time.Now()
 		isDecreasing = true
 	}
+
+	if s.committedChannelCapacity > s.receivedEstimate {
+		s.params.Logger.Debugw("committing channel capacity(bps)", "from", s.committedChannelCapacity, "to", s.receivedEstimate)
+	}
 	s.committedChannelCapacity = s.receivedEstimate
 	s.lastCommitTime = time.Now()
 
-	s.params.Logger.Debugw("committing channel capacity", "capacity(bps)", s.committedChannelCapacity)
 	return
 }