Squashed 'livekit-server/' content from commit 154b4d26

git-subtree-dir: livekit-server
git-subtree-split: 154b4d26b769c68a03c096124094b97bf61a996f

pkg/rtc/unhandlesimulcast.go

@@ -0,0 +1,132 @@
+// 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 rtc
+
+import (
+	"github.com/pion/interceptor"
+	"github.com/pion/rtp"
+	"github.com/pion/sdp/v3"
+	"github.com/pion/webrtc/v4"
+
+	"github.com/livekit/livekit-server/pkg/sfu/utils"
+)
+
+const (
+	simulcastProbeCount = 10
+)
+
+type UnhandleSimulcastOption func(r *UnhandleSimulcastInterceptor) error
+
+func UnhandleSimulcastTracks(tracks map[uint32]SimulcastTrackInfo) UnhandleSimulcastOption {
+	return func(r *UnhandleSimulcastInterceptor) error {
+		r.simTracks = tracks
+		return nil
+	}
+}
+
+type UnhandleSimulcastInterceptorFactory struct {
+	opts []UnhandleSimulcastOption
+}
+
+func (f *UnhandleSimulcastInterceptorFactory) NewInterceptor(id string) (interceptor.Interceptor, error) {
+	i := &UnhandleSimulcastInterceptor{simTracks: map[uint32]SimulcastTrackInfo{}}
+	for _, o := range f.opts {
+		if err := o(i); err != nil {
+			return nil, err
+		}
+	}
+	return i, nil
+}
+
+func NewUnhandleSimulcastInterceptorFactory(opts ...UnhandleSimulcastOption) (*UnhandleSimulcastInterceptorFactory, error) {
+	return &UnhandleSimulcastInterceptorFactory{opts: opts}, nil
+}
+
+type unhandleSimulcastRTPReader struct {
+	SimulcastTrackInfo
+	tryTimes            int
+	reader              interceptor.RTPReader
+	midExtensionID      uint8
+	streamIDExtensionID uint8
+}
+
+func (r *unhandleSimulcastRTPReader) Read(b []byte, a interceptor.Attributes) (int, interceptor.Attributes, error) {
+	n, a, err := r.reader.Read(b, a)
+	if r.tryTimes < 0 || err != nil {
+		return n, a, err
+	}
+
+	header := rtp.Header{}
+	hsize, err := header.Unmarshal(b[:n])
+	if err != nil {
+		return n, a, nil
+	}
+	var mid, rid string
+	if payload := header.GetExtension(r.midExtensionID); payload != nil {
+		mid = string(payload)
+	}
+
+	if payload := header.GetExtension(r.streamIDExtensionID); payload != nil {
+		rid = string(payload)
+	}
+
+	if mid != "" && rid != "" {
+		r.tryTimes = -1
+		return n, a, nil
+	}
+
+	r.tryTimes--
+
+	if mid == "" {
+		header.SetExtension(r.midExtensionID, []byte(r.Mid))
+	}
+	if rid == "" {
+		header.SetExtension(r.streamIDExtensionID, []byte(r.Rid))
+	}
+
+	hsize2 := header.MarshalSize()
+
+	if hsize2-hsize+n > len(b) { // no enough buf to set extension
+		return n, a, nil
+	}
+	copy(b[hsize2:], b[hsize:n])
+	header.MarshalTo(b)
+	return hsize2 - hsize + n, a, nil
+}
+
+type UnhandleSimulcastInterceptor struct {
+	interceptor.NoOp
+	simTracks map[uint32]SimulcastTrackInfo
+}
+
+func (u *UnhandleSimulcastInterceptor) BindRemoteStream(info *interceptor.StreamInfo, reader interceptor.RTPReader) interceptor.RTPReader {
+	if t, ok := u.simTracks[info.SSRC]; ok {
+		// if we support fec for simulcast streams at future, should get rsid extensions
+		midExtensionID := utils.GetHeaderExtensionID(info.RTPHeaderExtensions, webrtc.RTPHeaderExtensionCapability{URI: sdp.SDESMidURI})
+		streamIDExtensionID := utils.GetHeaderExtensionID(info.RTPHeaderExtensions, webrtc.RTPHeaderExtensionCapability{URI: sdp.SDESRTPStreamIDURI})
+		if midExtensionID == 0 || streamIDExtensionID == 0 {
+			return reader
+		}
+
+		return &unhandleSimulcastRTPReader{
+			SimulcastTrackInfo:  t,
+			reader:              reader,
+			tryTimes:            simulcastProbeCount,
+			midExtensionID:      uint8(midExtensionID),
+			streamIDExtensionID: uint8(streamIDExtensionID),
+		}
+	}
+	return reader
+}