hls: send PCR once, at the beginning of every TS segment

bluenviron · Aug 14, 2021 · 93b1433 · 93b1433
1 parent 2d71e69
commit 93b1433
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Showing 2 changed files with 39 additions and 25 deletions.
diff --git a/internal/hls/muxer.go b/internal/hls/muxer.go
@@ -34,14 +34,14 @@ type Muxer struct {
  h264SPS []byte
  h264PPS []byte
  aacConfig rtpaac.MPEG4AudioConfig
- startPCR time.Time
  videoDTSEst *h264.DTSEstimator
  audioAUCount int
  tsCurrent *tsFile
  tsQueue []*tsFile
  tsByName map[string]*tsFile
  tsDeleteCount int
  mutex sync.RWMutex
+ startPCR time.Time
  startPTS time.Duration
 }
 
@@ -82,7 +82,6 @@ func NewMuxer(
  h264SPS: h264SPS,
  h264PPS: h264PPS,
  aacConfig: aacConfig,
- startPCR: time.Now(),
  videoDTSEst: h264.NewDTSEstimator(),
  tsCurrent: newTSFile(videoTrack, audioTrack),
  tsByName: make(map[string]*tsFile),
@@ -122,11 +121,10 @@ func (m *Muxer) WriteH264(pts time.Duration, nalus [][]byte) error {
  if idrPresent &&
  m.tsCurrent.firstPacketWritten &&
  m.tsCurrent.duration() >= m.hlsSegmentDuration {
- if m.tsCurrent != nil {
- m.tsCurrent.close()
- }
+ m.tsCurrent.close()
 
  m.tsCurrent = newTSFile(m.videoTrack, m.audioTrack)
+ m.tsCurrent.setStartPCR(m.startPCR)
 
  m.tsByName[m.tsCurrent.name] = m.tsCurrent
  m.tsQueue = append(m.tsQueue, m.tsCurrent)
@@ -136,11 +134,12 @@ func (m *Muxer) WriteH264(pts time.Duration, nalus [][]byte) error {
  m.tsDeleteCount++
  }
  } else if !m.tsCurrent.firstPacketWritten {
+ m.startPCR = time.Now()
  m.startPTS = pts
+ m.tsCurrent.setStartPCR(m.startPCR)
  }
 
  pts = pts + ptsOffset - m.startPTS
- m.tsCurrent.setPCR(time.Since(m.startPCR))
  err := m.tsCurrent.writeH264(
  m.h264SPS,
  m.h264PPS,
@@ -164,13 +163,13 @@ func (m *Muxer) WriteAAC(pts time.Duration, aus [][]byte) error {
  if m.audioAUCount >= segmentMinAUCount &&
  m.tsCurrent.firstPacketWritten &&
  m.tsCurrent.duration() >= m.hlsSegmentDuration {
-
- if m.tsCurrent != nil {
- m.tsCurrent.close()
- }
+ m.tsCurrent.close()
 
  m.audioAUCount = 0
+
  m.tsCurrent = newTSFile(m.videoTrack, m.audioTrack)
+ m.tsCurrent.setStartPCR(m.startPCR)
+
  m.tsByName[m.tsCurrent.name] = m.tsCurrent
  m.tsQueue = append(m.tsQueue, m.tsCurrent)
  if len(m.tsQueue) > m.hlsSegmentCount {
@@ -179,7 +178,9 @@ func (m *Muxer) WriteAAC(pts time.Duration, aus [][]byte) error {
  m.tsDeleteCount++
  }
  } else if !m.tsCurrent.firstPacketWritten {
+ m.startPCR = time.Now()
  m.startPTS = pts
+ m.tsCurrent.setStartPCR(m.startPCR)
  }
  } else {
  if !m.tsCurrent.firstPacketWritten {
@@ -192,8 +193,6 @@ func (m *Muxer) WriteAAC(pts time.Duration, aus [][]byte) error {
  for i, au := range aus {
  auPTS := pts + time.Duration(i)*1000*time.Second/time.Duration(m.aacConfig.SampleRate)
 
- m.audioAUCount++
- m.tsCurrent.setPCR(time.Since(m.startPCR))
  err := m.tsCurrent.writeAAC(
  m.aacConfig.SampleRate,
  m.aacConfig.ChannelCount,
@@ -202,6 +201,8 @@ func (m *Muxer) WriteAAC(pts time.Duration, aus [][]byte) error {
  if err != nil {
  return err
  }
+
+ m.audioAUCount++
  }
 
  return nil

diff --git a/internal/hls/tsfile.go b/internal/hls/tsfile.go
@@ -18,10 +18,10 @@ type tsFile struct {
  name string
  buf *multiAccessBuffer
  mux *astits.Muxer
- pcr time.Duration
  firstPacketWritten bool
  minPTS time.Duration
  maxPTS time.Duration
+ startPCR time.Time
 }
 
 func newTSFile(videoTrack *gortsplib.Track, audioTrack *gortsplib.Track) *tsFile {
@@ -69,8 +69,8 @@ func (t *tsFile) duration() time.Duration {
  return t.maxPTS - t.minPTS
 }
 
-func (t *tsFile) setPCR(pcr time.Duration) {
- t.pcr = pcr
+func (t *tsFile) setStartPCR(startPCR time.Time) {
+ t.startPCR = startPCR
 }
 
 func (t *tsFile) newReader() io.Reader {
@@ -81,7 +81,6 @@ func (t *tsFile) writeH264(
  h264SPS []byte, h264PPS []byte,
  dts time.Duration, pts time.Duration, isIDR bool, nalus [][]byte) error {
  if !t.firstPacketWritten {
- t.firstPacketWritten = true
  t.minPTS = pts
  t.maxPTS = pts
  } else {
@@ -115,17 +114,30 @@ func (t *tsFile) writeH264(
  filteredNALUs = append(filteredNALUs, nalu)
  }
 
+ var af *astits.PacketAdaptationField
+
+ if isIDR {
+ if af == nil {
+ af = &astits.PacketAdaptationField{}
+ }
+ af.RandomAccessIndicator = true
+ }
+
+ if !t.firstPacketWritten {
+ t.firstPacketWritten = true
+ if af == nil {
+ af = &astits.PacketAdaptationField{}
+ }
+ af.HasPCR = true
+ pcr := time.Since(t.startPCR)
+ af.PCR = &astits.ClockReference{Base: int64(pcr.Seconds() * 90000)}
+ }
+
  enc, err := h264.EncodeAnnexB(filteredNALUs)
  if err != nil {
  return err
  }
 
- af := &astits.PacketAdaptationField{
- RandomAccessIndicator: isIDR,
- HasPCR: true,
- PCR: &astits.ClockReference{Base: int64(t.pcr.Seconds() * 90000)},
- }
-
  _, err = t.mux.WriteData(&astits.MuxerData{
  PID: 256,
  AdaptationField: af,
@@ -148,7 +160,6 @@ func (t *tsFile) writeH264(
 func (t *tsFile) writeAAC(sampleRate int, channelCount int, pts time.Duration, au []byte) error {
  if t.videoTrack == nil {
  if !t.firstPacketWritten {
- t.firstPacketWritten = true
  t.minPTS = pts
  t.maxPTS = pts
  } else {
@@ -176,9 +187,11 @@ func (t *tsFile) writeAAC(sampleRate int, channelCount int, pts time.Duration, a
  RandomAccessIndicator: true,
  }
 
- if t.videoTrack == nil {
+ if t.videoTrack == nil && !t.firstPacketWritten {
+ t.firstPacketWritten = true
  af.HasPCR = true
- af.PCR = &astits.ClockReference{Base: int64(t.pcr.Seconds() * 90000)}
+ pcr := time.Since(t.startPCR)
+ af.PCR = &astits.ClockReference{Base: int64(pcr.Seconds() * 90000)}
  }
 
  _, err = t.mux.WriteData(&astits.MuxerData{