Squelching DD reader error. (#2215)

Squelching Structure is nil error as it can happen on packets
received before a key frame is received.

pkg/sfu/buffer/buffer.go

@@ -31,6 +31,7 @@ import (
 	"go.uber.org/atomic"
 
 	"github.com/livekit/livekit-server/pkg/sfu/audio"
+	dd "github.com/livekit/livekit-server/pkg/sfu/dependencydescriptor"
 	"github.com/livekit/livekit-server/pkg/sfu/utils"
 	sutils "github.com/livekit/livekit-server/pkg/utils"
 	"github.com/livekit/mediatransportutil"
@@ -39,8 +40,6 @@ import (
 	"github.com/livekit/mediatransportutil/pkg/twcc"
 	"github.com/livekit/protocol/livekit"
 	"github.com/livekit/protocol/logger"
-
-	dd "github.com/livekit/livekit-server/pkg/sfu/dependencydescriptor"
 )
 
 const (
@@ -615,7 +614,7 @@ func (b *Buffer) getExtPacket(rtpPacket *rtp.Packet, arrivalTime time.Time, flow
 	if b.ddParser != nil {
 		ddVal, videoLayer, err := b.ddParser.Parse(ep.Packet)
 		if err != nil {
-			if err != ErrFrameEarlierThanKeyFrame {
+			if !errors.Is(err, ErrFrameEarlierThanKeyFrame) && !errors.Is(err, dd.ErrDDReaderNoStructure) {
 				b.logger.Warnw("could not parse dependency descriptor", err)
 			}
 			return nil

pkg/sfu/dependencydescriptor/dependencydescriptorreader.go

@@ -18,6 +18,18 @@ import (
 	"errors"
 )
 
+var (
+	ErrDDReaderNoStructure              = errors.New("DependencyDescriptorReader: Structure is nil")
+	ErrDDReaderTemplateWithoutStructure = errors.New("DependencyDescriptorReader: has templateDependencyStructurePresentFlag but AttachedStructure is nil")
+	ErrDDReaderTooManyTemplates         = errors.New("DependencyDescriptorReader: too many templates")
+	ErrDDReaderTooManyTemporalLayers    = errors.New("DependencyDescriptorReader: too many temporal layers")
+	ErrDDReaderTooManySpatialLayers     = errors.New("DependencyDescriptorReader: too many spatial layers")
+	ErrDDReaderInvalidTemplateIndex     = errors.New("DependencyDescriptorReader: invalid template index")
+	ErrDDReaderInvalidSpatialLayer      = errors.New("DependencyDescriptorReader: invalid spatial layer, should be less than the number of resolutions")
+	ErrDDReaderNumDTIMismatch           = errors.New("DependencyDescriptorReader: decode target indications length mismatch with structure num decode targets")
+	ErrDDReaderNumChainDiffsMismatch    = errors.New("DependencyDescriptorReader: chain diffs length mismatch with structure num chains")
+)
+
 type DependencyDescriptorReader struct {
 	// Output.
 	descriptor *DependencyDescriptor
@@ -59,7 +71,7 @@ func (r *DependencyDescriptorReader) Parse() (int, error) {
 
 	if r.structure == nil {
 		r.buffer.Invalidate()
-		return 0, errors.New("DependencyDescriptorReader: Structure is nil")
+		return 0, ErrDDReaderNoStructure
 	}
 
 	if r.activeDecodeTargetsPresentFlag {
@@ -140,7 +152,7 @@ func (r *DependencyDescriptorReader) readExtendedFields() error {
 			return err
 		}
 		if r.descriptor.AttachedStructure == nil {
-			return errors.New("DependencyDescriptorReader: has templateDependencyStructurePresentFlag but AttachedStructure is nil")
+			return ErrDDReaderTemplateWithoutStructure
 		}
 		bitmask := uint32((uint64(1) << r.descriptor.AttachedStructure.NumDecodeTargets) - 1)
 		r.descriptor.ActiveDecodeTargetsBitmask = &bitmask
@@ -203,7 +215,7 @@ func (r *DependencyDescriptorReader) readTemplateLayers() error {
 	)
 	for {
 		if len(templates) == MaxTemplates {
-			return errors.New("DependencyDescriptorReader: too many templates")
+			return ErrDDReaderTooManyTemplates
 		}
 
 		var lastTemplate FrameDependencyTemplate
@@ -220,13 +232,13 @@ func (r *DependencyDescriptorReader) readTemplateLayers() error {
 		if nextLayerIdc == nextTemporalLayer {
 			temporalId++
 			if temporalId >= MaxTemporalIds {
-				return errors.New("DependencyDescriptorReader: too many temporal layers")
+				return ErrDDReaderTooManyTemporalLayers
 			}
 		} else if nextLayerIdc == nextSpatialLayer {
 			spatialId++
 			temporalId = 0
 			if spatialId >= MaxSpatialIds {
-				return errors.New("DependencyDescriptorReader: too many spatial layers")
+				return ErrDDReaderTooManySpatialLayers
 			}
 		}
 
@@ -340,7 +352,7 @@ func (r *DependencyDescriptorReader) readFrameDependencyDefinition() error {
 
 	if templateIndex >= len(r.structure.Templates) {
 		r.buffer.Invalidate()
-		return errors.New("DependencyDescriptorReader: invalid template index")
+		return ErrDDReaderInvalidTemplateIndex
 	}
 
 	// Copy all the fields from the matching template
@@ -374,7 +386,7 @@ func (r *DependencyDescriptorReader) readFrameDependencyDefinition() error {
 		// then each spatial layer got one.
 		if r.descriptor.FrameDependencies.SpatialId >= len(r.structure.Resolutions) {
 			r.buffer.Invalidate()
-			return errors.New("DependencyDescriptorReader: invalid spatial layer, should be less than the number of resolutions")
+			return ErrDDReaderInvalidSpatialLayer
 		}
 		res := r.structure.Resolutions[r.descriptor.FrameDependencies.SpatialId]
 		r.descriptor.Resolution = &res
@@ -385,7 +397,7 @@ func (r *DependencyDescriptorReader) readFrameDependencyDefinition() error {
 
 func (r *DependencyDescriptorReader) readFrameDtis() error {
 	if len(r.descriptor.FrameDependencies.DecodeTargetIndications) != r.structure.NumDecodeTargets {
-		return errors.New("DependencyDescriptorReader: decode target indications length mismatch with structure num decode targets")
+		return ErrDDReaderNumDTIMismatch
 	}
 
 	for i := range r.descriptor.FrameDependencies.DecodeTargetIndications {
@@ -420,7 +432,7 @@ func (r *DependencyDescriptorReader) readFrameFdiffs() error {
 
 func (r *DependencyDescriptorReader) readFrameChains() error {
 	if len(r.descriptor.FrameDependencies.ChainDiffs) != r.structure.NumChains {
-		return errors.New("DependencyDescriptorReader: chain diffs length mismatch with structure num chains")
+		return ErrDDReaderNumChainDiffsMismatch
 	}
 
 	for i := range r.descriptor.FrameDependencies.ChainDiffs {