mirror of
https://github.com/hanzoai/livekit.git
synced 2026-10-30 18:29:34 +00:00
Raja SubramanianandGitHub
233190bd9a
* Add support for "abs-capture-time" extension. Currently, it is just passed through from publisher -> subscriber side. TODO: Need to store in sequencer and restore for retransmission. * abs-capture-time in retransmissions * clean up * fix test * more test fixes * more test fixes * more test fixes * log only when size is non-zero * log on both sides for debugging * add marshal/unmarshal * normalize abs capture time to SFU clock * comment out adding abs-capture-time from registered extensions
115 lines
4.0 KiB
Go
115 lines
4.0 KiB
Go
// Copyright 2024 LiveKit, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package abscapturetime
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import (
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"encoding/binary"
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"errors"
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"time"
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"github.com/livekit/mediatransportutil"
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)
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const (
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AbsCaptureTimeURI = "http://www.webrtc.org/experiments/rtp-hdrext/abs-capture-time"
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)
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var (
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errInvalidData = errors.New("invalid data")
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errTooSmall = errors.New("buffer too small")
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)
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// Reference: https://webrtc.googlesource.com/src/+/refs/heads/main/docs/native-code/rtp-hdrext/abs-capture-time/
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//
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// Data layout of the shortened version of abs-capture-time with a 1-byte header + 8 bytes of data:
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//
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// 0 1 2 3
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// 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
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | ID | len=7 | absolute capture timestamp (bit 0-23) |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | absolute capture timestamp (bit 24-55) |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | ... (56-63) |
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// +-+-+-+-+-+-+-+-+
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//
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//Data layout of the extended version of abs-capture-time with a 1-byte header + 16 bytes of data:
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//
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// 0 1 2 3
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// 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
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | ID | len=15| absolute capture timestamp (bit 0-23) |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | absolute capture timestamp (bit 24-55) |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | ... (56-63) | estimated capture clock offset (bit 0-23) |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | estimated capture clock offset (bit 24-55) |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | ... (56-63) |
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// +-+-+-+-+-+-+-+-+
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type AbsCaptureTime struct {
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absoluteCaptureTimestamp mediatransportutil.NtpTime
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estimatedCaptureClockOffset int64
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}
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func AbsCaptureTimeFromValue(absoluteCaptureTimestamp uint64, estimatedCaptureClockOffset int64) *AbsCaptureTime {
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return &AbsCaptureTime{
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absoluteCaptureTimestamp: mediatransportutil.NtpTime(absoluteCaptureTimestamp),
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estimatedCaptureClockOffset: estimatedCaptureClockOffset,
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}
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}
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func (a *AbsCaptureTime) Rewrite(offset time.Duration) error {
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if a.absoluteCaptureTimestamp == 0 {
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return errInvalidData
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}
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capturedAt := a.absoluteCaptureTimestamp.Time().Add(offset)
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a.absoluteCaptureTimestamp = mediatransportutil.ToNtpTime(capturedAt)
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a.estimatedCaptureClockOffset = 0
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return nil
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}
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func (a *AbsCaptureTime) Marshal() ([]byte, error) {
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if a.absoluteCaptureTimestamp == 0 {
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return nil, errInvalidData
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}
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size := 8
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if a.estimatedCaptureClockOffset != 0 {
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size += 8
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}
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marshalled := make([]byte, size)
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binary.BigEndian.PutUint64(marshalled, uint64(a.absoluteCaptureTimestamp))
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if a.estimatedCaptureClockOffset != 0 {
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binary.BigEndian.PutUint64(marshalled[8:], uint64(a.estimatedCaptureClockOffset))
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}
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return marshalled, nil
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}
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func (a *AbsCaptureTime) Unmarshal(marshalled []byte) error {
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if len(marshalled) < 8 {
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return errTooSmall
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}
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a.absoluteCaptureTimestamp = mediatransportutil.NtpTime(binary.BigEndian.Uint64(marshalled))
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if len(marshalled) >= 16 {
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a.estimatedCaptureClockOffset = int64(binary.BigEndian.Uint64(marshalled[8:]))
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}
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return nil
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}
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