use default max playout delay as chrome (#2411)

pkg/sfu/playoutdelay.go

@@ -46,8 +46,11 @@ type PlayoutDelayController struct {
 }
 
 func NewPlayoutDelayController(minDelay, maxDelay uint32, logger logger.Logger, rtpStats *buffer.RTPStatsSender) (*PlayoutDelayController, error) {
-	if maxDelay == 0 || maxDelay > rtpextension.PlayoutDelayDefaultMax {
-		maxDelay = rtpextension.PlayoutDelayDefaultMax
+	if maxDelay == 0 && minDelay > 0 {
+		maxDelay = rtpextension.MaxPlayoutDelayDefault
+	}
+	if maxDelay > rtpextension.PlayoutDelayMaxValue {
+		maxDelay = rtpextension.PlayoutDelayMaxValue
 	}
 	c := &PlayoutDelayController{
 		currentDelay: minDelay,

pkg/sfu/rtpextension/playoutdelay.go

@@ -7,7 +7,8 @@ import (
 
 const (
 	PlayoutDelayURI        = "http://www.webrtc.org/experiments/rtp-hdrext/playout-delay"
-	PlayoutDelayDefaultMax = 4000 // 4s
+	MaxPlayoutDelayDefault = 10000            // 10s, equal to chrome's default max playout delay
+	PlayoutDelayMaxValue   = 10 * (1<<12 - 1) // max value for playout delay can be represented
 
 	playoutDelayExtensionSize = 3
 )
@@ -28,11 +29,11 @@ type PlayOutDelay struct {
 }
 
 func PlayoutDelayFromValue(min, max uint16) PlayOutDelay {
-	if min >= (1<<12)*10 {
-		min = (1<<12 - 1) * 10
+	if min > PlayoutDelayMaxValue {
+		min = PlayoutDelayMaxValue
 	}
-	if max >= (1<<12)*10 {
-		max = (1<<12 - 1) * 10
+	if max > PlayoutDelayMaxValue {
+		max = PlayoutDelayMaxValue
 	}
 	return PlayOutDelay{Min: min, Max: max}
 }

pkg/sfu/rtpextension/playoutdelay_test.go

@@ -32,4 +32,12 @@ func TestPlayoutDelay(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, uint16((1<<12)-1)*10, p5.Min)
 	require.Equal(t, uint16((1<<12)-1)*10, p5.Max)
+
+	p6 := PlayOutDelay{Min: 100, Max: PlayoutDelayMaxValue}
+	bytes, err := p6.Marshal()
+	require.NoError(t, err)
+	p6Unmarshal := PlayOutDelay{}
+	err = p6Unmarshal.Unmarshal(bytes)
+	require.NoError(t, err)
+	require.Equal(t, p6, p6Unmarshal)
 }