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fix bitrate controller
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Yohan Totting committed Jan 15, 2024
1 parent f9d2337 commit 2eda132
Showing 1 changed file with 114 additions and 26 deletions.
140 changes: 114 additions & 26 deletions bitratecontroller.go
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Original file line number Diff line number Diff line change
Expand Up @@ -43,6 +43,13 @@ func (c *bitrateClaim) Quality() QualityLevel {
return c.quality
}

func (c *bitrateClaim) Bitrate() uint32 {
c.mu.RLock()
defer c.mu.RUnlock()

return c.bitrate
}

func (c *bitrateClaim) isAllowToIncrease() bool {
c.mu.RLock()
defer c.mu.RUnlock()
Expand All @@ -56,6 +63,10 @@ func (c *bitrateClaim) isAllowToIncrease() bool {
return true
}

func (c *bitrateClaim) IsAdjustable() bool {
return c.track.IsSimulcast() || c.track.IsScaleable()
}

func (c *bitrateClaim) pushbackDelayCounter() {
c.mu.Lock()
defer c.mu.Unlock()
Expand All @@ -74,13 +85,15 @@ type bitrateController struct {
lastBitrateAdjustmentTS time.Time
client *Client
claims map[string]*bitrateClaim
useBandwidthEstimation bool
}

func newbitrateController(client *Client, intervalMonitor time.Duration, useBandwidthEstimation bool) *bitrateController {
bc := &bitrateController{
mu: sync.RWMutex{},
client: client,
claims: make(map[string]*bitrateClaim, 0),
mu: sync.RWMutex{},
client: client,
claims: make(map[string]*bitrateClaim, 0),
useBandwidthEstimation: useBandwidthEstimation,
}

if !useBandwidthEstimation {
Expand Down Expand Up @@ -379,7 +392,7 @@ func (bc *bitrateController) isThereNonScreenCanDecrease(lowestQuality QualityLe
defer bc.mu.RUnlock()

for _, claim := range bc.claims {
if !claim.track.IsScreen() && claim.quality > lowestQuality {
if !claim.track.IsScreen() && (claim.track.IsScaleable() || claim.track.IsSimulcast()) && claim.quality > lowestQuality {
return true
}
}
Expand Down Expand Up @@ -445,14 +458,27 @@ func (bc *bitrateController) start() {
}()
}

func (bc *bitrateController) canDecreaseBitrate() bool {
claims := bc.Claims()

for _, claim := range claims {
if claim.IsAdjustable() &&
claim.Quality() > QualityLow {
return true
}
}

return false
}

func (bc *bitrateController) needIncreaseBitrate(availableBw uint32) bool {
claims := bc.Claims()

for _, claim := range claims {
if claim.Quality() < QualityHigh {
if bc.isEnoughBandwidthToIncrase(availableBw, claim) {
return true
}
if claim.IsAdjustable() &&
claim.Quality() < claim.track.MaxQuality() &&
bc.isEnoughBandwidthToIncrase(availableBw, claim) {
return true
}
}

Expand All @@ -461,24 +487,87 @@ func (bc *bitrateController) needIncreaseBitrate(availableBw uint32) bool {

func (bc *bitrateController) MonitorBandwidth(estimator cc.BandwidthEstimator) {
estimator.OnTargetBitrateChange(func(bw int) {
var needAdjustment bool

totalSendBitrates := bc.totalSentBitrates()

availableBw := uint32(bw) - totalSendBitrates

if totalSendBitrates > uint32(bw) || (totalSendBitrates < uint32(bw) && bc.needIncreaseBitrate(availableBw)) {
if time.Since(bc.lastBitrateAdjustmentTS) > 500*time.Millisecond {
glog.Info("brcontroller: target bitrate changed to ", ThousandSeparator(bw), ", will check and adjust bitrates")
if totalSendBitrates < uint32(bw) {
if bw < int(bc.client.sfu.bitrateConfigs.VideoMid-bc.client.sfu.bitrateConfigs.VideoLow) {
return
}

bc.checkAndAdjustBitrates()
needAdjustment = bc.needIncreaseBitrate(availableBw)
} else {
needAdjustment = bc.canDecreaseBitrate()
}

bc.mu.Lock()
bc.lastBitrateAdjustmentTS = time.Now()
bc.mu.Unlock()
}
if !needAdjustment {
return
}

glog.Info("bitratecontroller: available bandwidth ", ThousandSeparator(int(bw)), " total bitrate ", ThousandSeparator(int(totalSendBitrates)))

bc.fitBitratesToBandwidth(uint32(bw))

bc.mu.Lock()
bc.lastBitrateAdjustmentTS = time.Now()
bc.mu.Unlock()

})
}

func (bc *bitrateController) fitBitratesToBandwidth(bw uint32) {
totalSentBitrates := bc.totalSentBitrates()

claims := bc.Claims()
if totalSentBitrates > bw {
// reduce bitrates
for i := QualityHigh; i > QualityLow; i-- {
for _, claim := range claims {
if claim.IsAdjustable() &&
claim.Quality() == QualityLevel(i) {
claim.track.RequestPLI()
glog.Info("bitratecontroller: reduce bitrate for track ", claim.track.ID(), " from ", claim.Quality(), " to ", claim.Quality()-1)
bc.setQuality(claim.track.ID(), claim.Quality()-1)

totalSentBitrates = bc.totalSentBitrates()

// check if the reduced bitrate is fit to the available bandwidth
if totalSentBitrates <= bw {
glog.Info("bitratecontroller: total sent bitrates ", ThousandSeparator(int(totalSentBitrates)), " available bandwidth ", ThousandSeparator(int(bw)))
return
}
}
}
}
} else {
// increase bitrates
for i := QualityLow; i < QualityHigh; i++ {
for _, claim := range claims {
if claim.IsAdjustable() &&
claim.Quality() == QualityLevel(i) {
oldBitrate := claim.Bitrate()
newBitrate := bc.client.SFU().QualityLevelToBitrate(claim.Quality() + 1)
bitrateIncrease := newBitrate - oldBitrate

// check if the bitrate increase will more than the available bandwidth
if totalSentBitrates+bitrateIncrease >= bw {
return
}

claim.track.RequestPLI()
glog.Info("bitratecontroller: increase bitrate for track ", claim.track.ID(), " from ", claim.Quality(), " to ", claim.Quality()+1)
bc.setQuality(claim.track.ID(), claim.Quality()+1)
// update current total bitrates
totalSentBitrates = bc.totalSentBitrates()
}
}
}
}
}

// checkAndAdjustBitrates will check if the available bandwidth is enough to send the current bitrate
// if not then it will try to reduce one by one of simulcast track quality until it fit the bandwidth
// if the bandwidth is enough to send the current bitrate, then it will try to increase the bitrate
Expand Down Expand Up @@ -527,7 +616,7 @@ func (bc *bitrateController) checkAndAdjustBitrates() {
}

for _, claim := range claims {
if claim.track.IsSimulcast() || claim.track.IsScaleable() {
if claim.IsAdjustable() {
maxQuality := claim.track.MaxQuality()
if claim.quality > claim.track.MaxQuality() {
bc.setQuality(claim.track.ID(), maxQuality)
Expand Down Expand Up @@ -575,7 +664,7 @@ func (bc *bitrateController) checkAndAdjustBitrates() {
}

} else if bitrateAdjustment == increaseBitrate {
if (claim.track.IsSimulcast() || claim.track.IsScaleable()) && claim.quality < QualityHigh {
if claim.IsAdjustable() && claim.quality < claim.track.MaxQuality() {
increasedQuality := claim.quality + 1

if claim.quality == QualityMid && noneCount+lowCount > 0 {
Expand Down Expand Up @@ -682,17 +771,16 @@ func (bc *bitrateController) getBitrateAdjustment(claim *bitrateClaim) bitrateAd
}
}

availableBandwidth := bc.client.GetEstimatedBandwidth()

if bc.client.estimator != nil {
if bc.useBandwidthEstimation {
availableBandwidth := bc.client.GetEstimatedBandwidth()
return bc.getBitrateBasedAdjustment(availableBandwidth, claim)
}

return bc.getLossBasedAdjustment(claim)
}

func (bc *bitrateController) getBitrateBasedAdjustment(bandwidth uint32, claim *bitrateClaim) bitrateAdjustment {
if claim.track.Kind() == webrtc.RTPCodecTypeAudio {
if claim.track.Kind() == webrtc.RTPCodecTypeAudio || !claim.IsAdjustable() {
return keepBitrate
}

Expand All @@ -712,7 +800,7 @@ func (bc *bitrateController) getBitrateBasedAdjustment(bandwidth uint32, claim *

return decreaseBitrate
} else if totalBitrates < bandwidth && claim.quality != QualityHigh {
if !claim.isAllowToIncrease() {
if !bc.useBandwidthEstimation && !claim.isAllowToIncrease() {
if bc.client.IsDebugEnabled() {
glog.Info("bitrate: track ", claim.track.ID(), " increase bitrate too fast, delay increase bitrate")
}
Expand All @@ -738,14 +826,14 @@ func (bc *bitrateController) getBitrateBasedAdjustment(bandwidth uint32, claim *
}

func (bc *bitrateController) isEnoughBandwidthToIncrase(bandwidthLeft uint32, claim *bitrateClaim) bool {
nextQuality := claim.quality + 1
nextQuality := claim.Quality() + 1

if nextQuality > QualityHigh {
return false
}

nextBitrate := bc.client.sfu.QualityLevelToBitrate(nextQuality)
currentBitrate := bc.client.sfu.QualityLevelToBitrate(claim.quality)
currentBitrate := bc.client.sfu.QualityLevelToBitrate(claim.Quality())

bandwidthGap := nextBitrate - currentBitrate

Expand All @@ -766,7 +854,7 @@ func (bc *bitrateController) getLossBasedAdjustment(claim *bitrateClaim) bitrate
glog.Info("bitrate: track ", claim.track.ID(), " lost ratio ", lostSentRatio, " can increase bitrate")
}

if !claim.isAllowToIncrease() {
if !bc.useBandwidthEstimation && !claim.isAllowToIncrease() {
if bc.client.IsDebugEnabled() {
glog.Info("bitrate: track ", claim.track.ID(), " increase bitrate too fast, delay increase bitrate")
}
Expand Down

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