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

pkg/sfu/interfaces.go

@@ -0,0 +1,189 @@
+// 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 sfu
+
+import (
+	"time"
+
+	"github.com/pion/rtcp"
+	"github.com/pion/webrtc/v4"
+
+	"github.com/livekit/mediatransportutil/pkg/codec"
+	"github.com/livekit/protocol/codecs/mime"
+	"github.com/livekit/protocol/livekit"
+
+	"github.com/livekit/livekit-server/pkg/sfu/buffer"
+	"github.com/livekit/livekit-server/pkg/sfu/bwe"
+)
+
+//go:generate go run github.com/maxbrunsfeld/counterfeiter/v6 -generate
+
+// TrackReceiver defines an interface receive media from remote peer
+//
+//counterfeiter:generate . TrackReceiver
+type TrackReceiver interface {
+	TrackID() livekit.TrackID
+	StreamID() string
+
+	// returns the initial codec of the receiver, it is determined by the track's codec
+	// and will not change if the codec changes during the session (publisher changes codec)
+	Codec() webrtc.RTPCodecParameters
+	Mime() mime.MimeType
+	VideoLayerMode() livekit.VideoLayer_Mode
+	HeaderExtensions() []webrtc.RTPHeaderExtensionParameter
+	IsClosed() bool
+
+	ReadRTP(buf []byte, layer uint8, esn uint64) (int, error)
+	GetLayeredBitrate() ([]int32, Bitrates)
+
+	GetAudioLevel() (float64, bool)
+
+	SendPLI(layer int32, force bool)
+
+	SetMaxExpectedSpatialLayer(layer int32)
+
+	AddDownTrack(track TrackSender) error
+	DeleteDownTrack(participantID livekit.ParticipantID)
+	GetDownTracks() []TrackSender
+
+	DebugInfo() map[string]any
+
+	TrackInfo() *livekit.TrackInfo
+	UpdateTrackInfo(ti *livekit.TrackInfo)
+
+	// Get primary receiver if this receiver represents a RED codec; otherwise it will return itself
+	GetPrimaryReceiverForRed() TrackReceiver
+
+	// Get red receiver for primary codec, used by forward red encodings for opus only codec
+	GetRedReceiver() TrackReceiver
+
+	GetTemporalLayerFpsForSpatial(layer int32) []float32
+
+	GetTrackStats() *livekit.RTPStats
+
+	// AddOnReady adds a function to be called when the receiver is ready, the callback
+	// could be called immediately if the receiver is ready when the callback is added
+	AddOnReady(func())
+
+	AddOnCodecStateChange(func(webrtc.RTPCodecParameters, ReceiverCodecState))
+	CodecState() ReceiverCodecState
+
+	// VideoSizes returns the video size parsed from rtp packet for each spatial layer.
+	VideoSizes() []codec.VideoSize
+
+	// closes all associated buffers and issues a resync to all attached downtracks so that
+	// they can resync and have proper sequncing without gaps in sequence numbers / timestamps
+	Restart(reason string)
+}
+
+// --------------------------------------
+
+//counterfeiter:generate . REDTransformer
+type REDTransformer interface {
+	TrackReceiver
+	SetLBThreshold(lbThreshold int)
+	ForwardRTP(pkt *buffer.ExtPacket, spatialLayer int32) int32
+	ForwardRTCPSenderReport(
+		payloadType webrtc.PayloadType,
+		layer int32,
+		publisherSRData *livekit.RTCPSenderReportState,
+	)
+	GetDownTracks() []TrackSender
+	ResyncDownTracks()
+	OnStreamRestart()
+	CanClose() bool
+	Close()
+}
+
+// --------------------------------------
+
+// TrackSender defines an interface send media to remote peer
+//
+//counterfeiter:generate . TrackSender
+type TrackSender interface {
+	UpTrackLayersChange()
+	UpTrackBitrateAvailabilityChange()
+	UpTrackMaxPublishedLayerChange(maxPublishedLayer int32)
+	UpTrackMaxTemporalLayerSeenChange(maxTemporalLayerSeen int32)
+	UpTrackBitrateReport(availableLayers []int32, bitrates Bitrates)
+	WriteRTP(p *buffer.ExtPacket, layer int32) int32
+	Close()
+	IsClosed() bool
+	// ID is the globally unique identifier for this Track.
+	ID() string
+	SubscriberID() livekit.ParticipantID
+	HandleRTCPSenderReportData(
+		payloadType webrtc.PayloadType,
+		layer int32,
+		publisherSRData *livekit.RTCPSenderReportState,
+	) error
+	Resync()
+	SetReceiver(TrackReceiver)
+	ReceiverRestart(TrackReceiver)
+}
+
+// -------------------------------------------------------------------
+
+//counterfeiter:generate . DownTrackStreamAllocatorListener
+type DownTrackStreamAllocatorListener interface {
+	// RTCP received
+	OnREMB(dt *DownTrack, remb *rtcp.ReceiverEstimatedMaximumBitrate)
+	OnTransportCCFeedback(dt *DownTrack, cc *rtcp.TransportLayerCC)
+
+	// video layer availability changed
+	OnAvailableLayersChanged(dt *DownTrack)
+
+	// video layer bitrate availability changed
+	OnBitrateAvailabilityChanged(dt *DownTrack)
+
+	// max published spatial layer changed
+	OnMaxPublishedSpatialChanged(dt *DownTrack)
+
+	// max published temporal layer changed
+	OnMaxPublishedTemporalChanged(dt *DownTrack)
+
+	// subscription changed - mute/unmute
+	OnSubscriptionChanged(dt *DownTrack)
+
+	// subscribed max video layer changed
+	OnSubscribedLayerChanged(dt *DownTrack, layers buffer.VideoLayer)
+
+	// stream resumed
+	OnResume(dt *DownTrack)
+
+	// check if track should participate in BWE
+	IsBWEEnabled(dt *DownTrack) bool
+
+	// get the BWE type in use
+	BWEType() bwe.BWEType
+
+	// check if subscription mute can be applied
+	IsSubscribeMutable(dt *DownTrack) bool
+}
+
+// -------------------------------------------------------------------
+
+//counterfeiter:generate . DownTrackListener
+type DownTrackListener interface {
+	OnBindAndConnected()
+	OnStatsUpdate(stat *livekit.AnalyticsStat)
+	OnMaxSubscribedLayerChanged(layer int32)
+	OnRttUpdate(rtt uint32)
+	OnCodecNegotiated(webrtc.RTPCodecCapability)
+	OnDownTrackClose(isExpectedToResume bool)
+	OnStreamStarted(elapsed time.Duration)
+}
+
+// -------------------------------------------------------------------