snapshot of https://github.com/livekit/livekit.git @ 08c5433449c106943231037d0b892895f6e92d3b (2026-09-15)

pkg/sfu/pacer/base.go

@@ -0,0 +1,138 @@
+// Copyright 2023 LiveKit, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package pacer
+
+import (
+	"errors"
+	"io"
+	"time"
+
+	"github.com/livekit/livekit-server/pkg/sfu/bwe"
+	"github.com/livekit/mediatransportutil"
+	"github.com/livekit/protocol/logger"
+	"github.com/livekit/protocol/utils/mono"
+	"github.com/pion/rtp"
+	"go.uber.org/atomic"
+)
+
+type Base struct {
+	logger logger.Logger
+
+	bwe bwe.BWE
+
+	lastPacketSentAt atomic.Int64
+
+	*ProbeObserver
+}
+
+func NewBase(logger logger.Logger, bwe bwe.BWE) *Base {
+	return &Base{
+		logger:        logger,
+		bwe:           bwe,
+		ProbeObserver: NewProbeObserver(logger),
+	}
+}
+
+func (b *Base) SetInterval(_interval time.Duration) {
+}
+
+func (b *Base) SetBitrate(_bitrate int) {
+}
+
+func (b *Base) TimeSinceLastSentPacket() time.Duration {
+	return time.Duration(mono.UnixNano() - b.lastPacketSentAt.Load())
+}
+
+func (b *Base) SendPacket(p *Packet) (int, error) {
+	defer func() {
+		if p.HeaderPool != nil && p.Header != nil {
+			*p.Header = rtp.Header{}
+			p.HeaderPool.Put(p.Header)
+		}
+
+		if p.Pool != nil && p.PoolEntity != nil {
+			p.Pool.Put(p.PoolEntity)
+		}
+
+		*p = Packet{}
+		PacketFactory.Put(p)
+	}()
+
+	err := b.patchRTPHeaderExtensions(p)
+	if err != nil {
+		b.logger.Errorw("patching rtp header extensions err", err)
+		return 0, err
+	}
+
+	var written int
+	written, err = p.WriteStream.WriteRTP(p.Header, p.Payload)
+	if err != nil {
+		if !errors.Is(err, io.ErrClosedPipe) {
+			b.logger.Errorw("write rtp packet failed", err)
+		}
+		return 0, err
+	}
+
+	return written, nil
+}
+
+// patch just abs-send-time and transport-cc extensions if applicable
+func (b *Base) patchRTPHeaderExtensions(p *Packet) error {
+	sendingAt := mono.Now()
+	if p.AbsSendTimeExtID != 0 {
+		absSendTimeExt := rtp.AbsSendTimeExtension{
+			Timestamp: uint64(mediatransportutil.ToNtpTime(sendingAt) >> 14),
+		}
+		absSendTimeBytes, err := absSendTimeExt.Marshal()
+		if err != nil {
+			return err
+		}
+
+		if err = p.Header.SetExtension(p.AbsSendTimeExtID, absSendTimeBytes); err != nil {
+			return err
+		}
+
+		b.lastPacketSentAt.Store(sendingAt.UnixNano())
+	}
+
+	packetSize := p.HeaderSize + len(p.Payload)
+	if p.TransportWideExtID != 0 && b.bwe != nil {
+		twccSN := b.bwe.RecordPacketSendAndGetSequenceNumber(
+			sendingAt.UnixMicro(),
+			packetSize,
+			p.IsRTX,
+			p.ProbeClusterId,
+			p.IsProbe,
+		)
+		twccExt := rtp.TransportCCExtension{
+			TransportSequence: twccSN,
+		}
+		twccExtBytes, err := twccExt.Marshal()
+		if err != nil {
+			return err
+		}
+
+		if err = p.Header.SetExtension(p.TransportWideExtID, twccExtBytes); err != nil {
+			return err
+		}
+
+		b.lastPacketSentAt.Store(sendingAt.UnixNano())
+	}
+
+	b.ProbeObserver.RecordPacket(packetSize, p.IsRTX, p.ProbeClusterId, p.IsProbe)
+	return nil
+}
+
+// ------------------------------------------------