move subfolders in pkg/

pkg/rtcpreceiver/rtcpreceiver.go

@@ -0,0 +1,93 @@
+// Package rtcpreceiver implements RTCP receiver reports.
+package rtcpreceiver
+
+import (
+	"math/rand"
+	"sync"
+
+	"github.com/pion/rtcp"
+
+	"github.com/aler9/gortsplib/pkg/base"
+)
+
+type frameRtpReq struct {
+	sequenceNumber uint16
+}
+
+type frameRtcpReq struct {
+	ssrc          uint32
+	ntpTimeMiddle uint32
+}
+
+type reportReq struct {
+	res chan []byte
+}
+
+// RtcpReceiver allows building RTCP receiver reports, by parsing
+// incoming frames.
+type RtcpReceiver struct {
+	mutex                sync.Mutex
+	publisherSSRC        uint32
+	receiverSSRC         uint32
+	sequenceNumberCycles uint16
+	lastSequenceNumber   uint16
+	lastSenderReport     uint32
+}
+
+// New allocates a RtcpReceiver.
+func New() *RtcpReceiver {
+	return &RtcpReceiver{
+		receiverSSRC: rand.Uint32(),
+	}
+}
+
+// OnFrame processes a RTP or RTCP frame and extract the data needed by RTCP receiver reports.
+func (rr *RtcpReceiver) OnFrame(streamType base.StreamType, buf []byte) {
+	rr.mutex.Lock()
+	defer rr.mutex.Unlock()
+
+	if streamType == base.StreamTypeRtp {
+		if len(buf) >= 3 {
+			// extract the sequence number of the first frame
+			sequenceNumber := uint16(uint16(buf[2])<<8 | uint16(buf[1]))
+
+			if sequenceNumber < rr.lastSequenceNumber {
+				rr.sequenceNumberCycles += 1
+			}
+			rr.lastSequenceNumber = sequenceNumber
+		}
+
+	} else {
+		// we can afford to unmarshal all RTCP frames
+		// since they are sent with a frequency much lower than the one of RTP frames
+		frames, err := rtcp.Unmarshal(buf)
+		if err == nil {
+			for _, frame := range frames {
+				if senderReport, ok := (frame).(*rtcp.SenderReport); ok {
+					rr.publisherSSRC = senderReport.SSRC
+					rr.lastSenderReport = uint32(senderReport.NTPTime >> 16)
+				}
+			}
+		}
+	}
+}
+
+// Report generates a RTCP receiver report.
+func (rr *RtcpReceiver) Report() []byte {
+	rr.mutex.Lock()
+	defer rr.mutex.Unlock()
+
+	report := &rtcp.ReceiverReport{
+		SSRC: rr.receiverSSRC,
+		Reports: []rtcp.ReceptionReport{
+			{
+				SSRC:               rr.publisherSSRC,
+				LastSequenceNumber: uint32(rr.sequenceNumberCycles)<<8 | uint32(rr.lastSequenceNumber),
+				LastSenderReport:   rr.lastSenderReport,
+			},
+		},
+	}
+
+	byts, _ := report.Marshal()
+	return byts
+}