hls muxer: fix bad computation of pts

internal/hls/muxer_ts_generator.go

@@ -11,9 +11,6 @@ import (
 )
 
 const (
-	// an offset between PCR and PTS/DTS is needed to avoid PCR > PTS
-	pcrOffset = 500 * time.Millisecond
-
 	segmentMinAUCount = 100
 )
 
@@ -108,11 +105,11 @@ func (m *muxerTSGenerator) writeH264(pts time.Duration, nalus [][]byte) error {
 		m.startPCR = now
 		m.currentSegment = newMuxerTSSegment(now, m.hlsSegmentMaxSize,
 			m.videoTrack, m.writer.WriteData)
-		m.startPTS = pts
 		m.videoDTSEst = h264.NewDTSEstimator()
-		pts = pcrOffset
+		m.startPTS = pts
+		pts = 0
 	} else {
-		pts = pts - m.startPTS + pcrOffset
+		pts -= m.startPTS
 
 		// switch segment
 		if idrPresent &&
@@ -125,7 +122,7 @@ func (m *muxerTSGenerator) writeH264(pts time.Duration, nalus [][]byte) error {
 		}
 	}
 
-	dts := m.videoDTSEst.Feed(pts-m.startPTS) + pcrOffset
+	dts := m.videoDTSEst.Feed(pts)
 
 	// prepend an AUD. This is required by video.js and iOS
 	filteredNALUs := [][]byte{
@@ -156,7 +153,8 @@ func (m *muxerTSGenerator) writeH264(pts time.Duration, nalus [][]byte) error {
 		return err
 	}
 
-	err = m.currentSegment.writeH264(now.Sub(m.startPCR), dts, pts, idrPresent, enc)
+	err = m.currentSegment.writeH264(now.Sub(m.startPCR), dts,
+		pts, idrPresent, enc)
 	if err != nil {
 		if m.currentSegment.buf.Len() > 0 {
 			m.streamPlaylist.pushSegment(m.currentSegment)
@@ -178,9 +176,9 @@ func (m *muxerTSGenerator) writeAAC(pts time.Duration, aus [][]byte) error {
 			m.currentSegment = newMuxerTSSegment(now, m.hlsSegmentMaxSize,
 				m.videoTrack, m.writer.WriteData)
 			m.startPTS = pts
-			pts = pcrOffset
+			pts = 0
 		} else {
-			pts = pts - m.startPTS + pcrOffset
+			pts -= m.startPTS
 
 			// switch segment
 			if m.currentSegment.audioAUCount >= segmentMinAUCount &&
@@ -198,7 +196,7 @@ func (m *muxerTSGenerator) writeAAC(pts time.Duration, aus [][]byte) error {
 			return nil
 		}
 
-		pts = pts - m.startPTS + pcrOffset
+		pts -= m.startPTS
 	}
 
 	pkts := make([]*aac.ADTSPacket, len(aus))

internal/hls/muxer_ts_segment.go

@@ -11,6 +11,11 @@ import (
 	"github.com/asticode/go-astits"
 )
 
+const (
+	// an offset between PCR and PTS/DTS is needed to avoid PCR > PTS
+	pcrOffset = 500 * time.Millisecond
+)
+
 type muxerTSSegment struct {
 	hlsSegmentMaxSize uint64
 	videoTrack        *gortsplib.TrackH264
@@ -93,11 +98,11 @@ func (t *muxerTSSegment) writeH264(
 
 	if dts == pts {
 		oh.PTSDTSIndicator = astits.PTSDTSIndicatorOnlyPTS
-		oh.PTS = &astits.ClockReference{Base: int64(pts.Seconds() * 90000)}
+		oh.PTS = &astits.ClockReference{Base: int64((pts + pcrOffset).Seconds() * 90000)}
 	} else {
 		oh.PTSDTSIndicator = astits.PTSDTSIndicatorBothPresent
-		oh.DTS = &astits.ClockReference{Base: int64(dts.Seconds() * 90000)}
-		oh.PTS = &astits.ClockReference{Base: int64(pts.Seconds() * 90000)}
+		oh.DTS = &astits.ClockReference{Base: int64((dts + pcrOffset).Seconds() * 90000)}
+		oh.PTS = &astits.ClockReference{Base: int64((pts + pcrOffset).Seconds() * 90000)}
 	}
 
 	_, err := t.writeData(&astits.MuxerData{
@@ -152,7 +157,7 @@ func (t *muxerTSSegment) writeAAC(
 				OptionalHeader: &astits.PESOptionalHeader{
 					MarkerBits:      2,
 					PTSDTSIndicator: astits.PTSDTSIndicatorOnlyPTS,
-					PTS:             &astits.ClockReference{Base: int64(pts.Seconds() * 90000)},
+					PTS:             &astits.ClockReference{Base: int64((pts + pcrOffset).Seconds() * 90000)},
 				},
 				PacketLength: uint16(len(enc) + 8),
 				StreamID:     192, // audio