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server/vendor/github.com/pion/rtp/abscapturetimeextension.go

@@ -0,0 +1,106 @@
+// SPDX-FileCopyrightText: 2023 The Pion community <https://pion.ly>
+// SPDX-License-Identifier: MIT
+
+package rtp
+
+import (
+	"encoding/binary"
+	"time"
+)
+
+const (
+	absCaptureTimeExtensionSize         = 8
+	absCaptureTimeExtendedExtensionSize = 16
+)
+
+// AbsCaptureTimeExtension is a extension payload format in
+// http://www.webrtc.org/experiments/rtp-hdrext/abs-capture-time
+// 0                   1                   2                   3
+// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+// |  ID   | len=7 |     absolute capture timestamp (bit 0-23)     |
+// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+// |             absolute capture timestamp (bit 24-55)            |
+// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+// |  ... (56-63)  |
+// +-+-+-+-+-+-+-+-+
+type AbsCaptureTimeExtension struct {
+	Timestamp                   uint64
+	EstimatedCaptureClockOffset *int64
+}
+
+// Marshal serializes the members to buffer.
+func (t AbsCaptureTimeExtension) Marshal() ([]byte, error) {
+	if t.EstimatedCaptureClockOffset != nil {
+		buf := make([]byte, 16)
+		binary.BigEndian.PutUint64(buf[0:8], t.Timestamp)
+		binary.BigEndian.PutUint64(buf[8:16], uint64(*t.EstimatedCaptureClockOffset))
+		return buf, nil
+	}
+	buf := make([]byte, 8)
+	binary.BigEndian.PutUint64(buf[0:8], t.Timestamp)
+	return buf, nil
+}
+
+// Unmarshal parses the passed byte slice and stores the result in the members.
+func (t *AbsCaptureTimeExtension) Unmarshal(rawData []byte) error {
+	if len(rawData) < absCaptureTimeExtensionSize {
+		return errTooSmall
+	}
+	t.Timestamp = binary.BigEndian.Uint64(rawData[0:8])
+	if len(rawData) >= absCaptureTimeExtendedExtensionSize {
+		offset := int64(binary.BigEndian.Uint64(rawData[8:16]))
+		t.EstimatedCaptureClockOffset = &offset
+	}
+	return nil
+}
+
+// CaptureTime produces the estimated time.Time represented by this extension.
+func (t AbsCaptureTimeExtension) CaptureTime() time.Time {
+	return toTime(t.Timestamp)
+}
+
+// EstimatedCaptureClockOffsetDuration produces the estimated time.Duration represented by this extension.
+func (t AbsCaptureTimeExtension) EstimatedCaptureClockOffsetDuration() *time.Duration {
+	if t.EstimatedCaptureClockOffset == nil {
+		return nil
+	}
+	offset := *t.EstimatedCaptureClockOffset
+	negative := false
+	if offset < 0 {
+		offset = -offset
+		negative = true
+	}
+	duration := time.Duration(offset/(1<<32))*time.Second + time.Duration((offset&0xFFFFFFFF)*1e9/(1<<32))*time.Nanosecond
+	if negative {
+		duration = -duration
+	}
+	return &duration
+}
+
+// NewAbsCaptureTimeExtension makes new AbsCaptureTimeExtension from time.Time.
+func NewAbsCaptureTimeExtension(captureTime time.Time) *AbsCaptureTimeExtension {
+	return &AbsCaptureTimeExtension{
+		Timestamp: toNtpTime(captureTime),
+	}
+}
+
+// NewAbsCaptureTimeExtensionWithCaptureClockOffset makes new AbsCaptureTimeExtension from time.Time and a clock offset.
+func NewAbsCaptureTimeExtensionWithCaptureClockOffset(captureTime time.Time, captureClockOffset time.Duration) *AbsCaptureTimeExtension {
+	ns := captureClockOffset.Nanoseconds()
+	negative := false
+	if ns < 0 {
+		ns = -ns
+		negative = true
+	}
+	lsb := (ns / 1e9) & 0xFFFFFFFF
+	msb := (((ns % 1e9) * (1 << 32)) / 1e9) & 0xFFFFFFFF
+	offset := (lsb << 32) | msb
+	if negative {
+		offset = -offset
+	}
+	return &AbsCaptureTimeExtension{
+		Timestamp:                   toNtpTime(captureTime),
+		EstimatedCaptureClockOffset: &offset,
+	}
+}