Recalc gap of sequence number after forcing rollover. (#2880)

pkg/sfu/buffer/buffer.go

@@ -827,9 +827,9 @@ func (b *Buffer) getExtPacket(rtpPacket *rtp.Packet, arrivalTime int64, flowStat
 		} else {
 			// vp8 with DependencyDescriptor enabled, use the TID from the descriptor
 			vp8Packet.TID = uint8(ep.Temporal)
-			ep.Spatial = InvalidLayerSpatial // vp8 don't have spatial scalability, reset to invalid
 		}
 		ep.Payload = vp8Packet
+		ep.Spatial = InvalidLayerSpatial // vp8 don't have spatial scalability, reset to invalid
 
 	case "video/vp9":
 		if ep.DependencyDescriptor == nil {
@@ -849,6 +849,7 @@ func (b *Buffer) getExtPacket(rtpPacket *rtp.Packet, arrivalTime int64, flowStat
 
 	case "video/h264":
 		ep.KeyFrame = IsH264KeyFrame(rtpPacket.Payload)
+		ep.Spatial = InvalidLayerSpatial // h.264 don't have spatial scalability, reset to invalid
 
 	case "video/av1":
 		ep.KeyFrame = IsAV1KeyFrame(rtpPacket.Payload)

pkg/sfu/buffer/rtpstats_receiver.go

@@ -227,7 +227,7 @@ func (r *RTPStatsReceiver) Update(
 		gapTS := int64(resTS.ExtendedVal - resTS.PreExtendedHighest)
 
 		// it is possible that sequence number has rolled over too
-		if gapSN < 0 && gapTS > 0 {
+		if gapSN < 0 && gapTS > 0 && payloadSize > 0 {
 			// not possible to know how many cycles of sequence number roll over could have happened,
 			// use 1 to ensure that it at least does not go backwards
 			resSN = r.sequenceNumber.Rollover(sequenceNumber, 1)
@@ -240,6 +240,7 @@ func (r *RTPStatsReceiver) Update(
 				"forcing sequence number rollover", nil,
 				getLoggingFields()...,
 			)
+			gapSN = int64(resSN.ExtendedVal - resSN.PreExtendedHighest)
 		}
 	}