From 793e61ac142fc2ccaee6190824a5ce7417da5277 Mon Sep 17 00:00:00 2001
From: Raja Subramanian <raja.gobi@tutanota.com>
Date: Tue, 4 Apr 2023 09:58:57 +0530
Subject: [PATCH] Use bandwidth requested from last allocation. (#1577)

* Use bandwidth requested from last allocation.

With overshoot/opportunistic forwarding, It is possible that
bitrate at target layers is 0. So, use bandwidth requested
from last allocation which shouold have a correct value.

Still need to think about using the latest bit rates to get
the requested bandwidth. It is possible that bitrates have
changed since last allocation. That was the idea behind using
the latest bitrates, but it could return 0. Accounting for it
runs into a few scenarios. Last allocation has number from
last allocation and is a good indicator of the need.

* race
---
 pkg/rtc/participant_internal_test.go |  4 ++--
 pkg/sfu/downtrack.go                 |  3 +--
 pkg/sfu/forwarder.go                 | 18 ++----------------
 3 files changed, 5 insertions(+), 20 deletions(-)

diff --git a/pkg/rtc/participant_internal_test.go b/pkg/rtc/participant_internal_test.go
index a182606e8..4d294c646 100644
--- a/pkg/rtc/participant_internal_test.go
+++ b/pkg/rtc/participant_internal_test.go
@@ -469,7 +469,7 @@ func TestPreferVideoCodecForPublisher(t *testing.T) {
 		participant.SetResponseSink(sink)
 		var answer webrtc.SessionDescription
 		var answerReceived atomic.Bool
-		sink.WriteMessageStub = func(msg proto.Message) error {
+		sink.WriteMessageCalls(func(msg proto.Message) error {
 			if res, ok := msg.(*livekit.SignalResponse); ok {
 				if res.GetAnswer() != nil {
 					answer = FromProtoSessionDescription(res.GetAnswer())
@@ -478,7 +478,7 @@ func TestPreferVideoCodecForPublisher(t *testing.T) {
 				}
 			}
 			return nil
-		}
+		})
 		participant.HandleOffer(sdp)
 
 		require.Eventually(t, func() bool { return answerReceived.Load() }, 5*time.Second, 10*time.Millisecond)
diff --git a/pkg/sfu/downtrack.go b/pkg/sfu/downtrack.go
index 4e89eed3e..0fee2e8ca 100644
--- a/pkg/sfu/downtrack.go
+++ b/pkg/sfu/downtrack.go
@@ -995,8 +995,7 @@ func (d *DownTrack) IsDeficient() bool {
 }
 
 func (d *DownTrack) BandwidthRequested() int64 {
-	_, brs := d.receiver.GetLayeredBitrate()
-	return d.forwarder.BandwidthRequested(brs)
+	return d.forwarder.BandwidthRequested()
 }
 
 func (d *DownTrack) DistanceToDesired() float64 {
diff --git a/pkg/sfu/forwarder.go b/pkg/sfu/forwarder.go
index fde7e1ccb..1ef7674f2 100644
--- a/pkg/sfu/forwarder.go
+++ b/pkg/sfu/forwarder.go
@@ -456,25 +456,11 @@ func (f *Forwarder) IsDeficient() bool {
 	return f.isDeficientLocked()
 }
 
-func (f *Forwarder) BandwidthRequested(brs Bitrates) int64 {
+func (f *Forwarder) BandwidthRequested() int64 {
 	f.lock.RLock()
 	defer f.lock.RUnlock()
 
-	if !f.targetLayers.IsValid() {
-		if f.targetLayers != buffer.InvalidLayers {
-			f.logger.Warnw(
-				"unexpected target layers", nil,
-				"target", f.targetLayers,
-				"current", f.currentLayers,
-				"parked", f.parkedLayers,
-				"max", f.maxLayers,
-				"lastAllocation", f.lastAllocation,
-			)
-		}
-		return 0
-	}
-
-	return brs[f.targetLayers.Spatial][f.targetLayers.Temporal]
+	return f.lastAllocation.BandwidthRequested
 }
 
 func (f *Forwarder) DistanceToDesired(availableLayers []int32, brs Bitrates) float64 {