Include jitter and delay in receiver reports.

jitter/jitter.go

@@ -0,0 +1,49 @@
+package jitter
+
+import (
+	"sync/atomic"
+
+	"sfu/mono"
+)
+
+type Estimator struct {
+	hz        uint32
+	timestamp uint32
+	time uint32
+
+	jitter uint32 // atomic
+}
+
+func New(hz uint32) *Estimator {
+	return &Estimator{hz: hz}
+}
+
+func (e *Estimator) accumulate(timestamp, now uint32) {
+	if e.time == 0 {
+		e.timestamp = timestamp
+		e.time = now
+	}
+
+	d := uint32((e.time - now) - (e.timestamp - timestamp))
+	if d & 0x80000000 != 0 {
+		d = uint32(-int32(d))
+	}
+	oldjitter := atomic.LoadUint32(&e.jitter)
+	jitter := (oldjitter * 15 + d) / 16
+	atomic.StoreUint32(&e.jitter, jitter)
+
+	e.timestamp = timestamp
+	e.time = now
+}
+
+func (e *Estimator) Accumulate(timestamp uint32) {
+	e.accumulate(timestamp, uint32(mono.Now(e.hz)))
+}
+
+func (e *Estimator) Jitter() uint32 {
+	return atomic.LoadUint32(&e.jitter)
+}
+
+func (e *Estimator) HZ() uint32 {
+	return e.hz
+}

jitter/jitter_test.go

@@ -0,0 +1,37 @@
+package jitter
+
+import (
+	"testing"
+)
+
+func TestJitter(t *testing.T) {
+	e := New(48000)
+	e.accumulate(0, 0)
+	e.accumulate(1000, 1000)
+	e.accumulate(2000, 2000)
+	e.accumulate(3000, 3000)
+
+	if e.Jitter() != 0 {
+		t.Errorf("Expected 0, got %v", e.Jitter())
+	}
+
+	e = New(48000)
+	e.accumulate(0, 0)
+	e.accumulate(1000, 1000)
+	e.accumulate(2000, 2200)
+	e.accumulate(3000, 3000)
+
+	if e.Jitter() != 23 {
+		t.Errorf("Expected 23, got %v", e.Jitter())
+	}
+
+	e = New(48000)
+	e.accumulate(0, 0)
+	e.accumulate(1000, 1000)
+	e.accumulate(2000, 1800)
+	e.accumulate(3000, 3000)
+
+	if e.Jitter() != 23 {
+		t.Errorf("Expected 23, got %v", e.Jitter())
+	}
+}