From bb8c02b9f0fd7286df2dce36b6927fe2a60bce48 Mon Sep 17 00:00:00 2001
From: Alessandro Ros <aler9.dev@gmail.com>
Date: Sat, 7 Oct 2023 17:36:57 +0200
Subject: [PATCH] fix 'fragment sequence discontinuity' warning when reading
 record segments with VLC (#2476)

---
 go.mod                     |  2 +-
 go.sum                     |  4 ++--
 internal/record/agent.go   | 13 +++++++------
 internal/record/part.go    | 20 ++++++++++++--------
 internal/record/segment.go |  6 ++++--
 5 files changed, 26 insertions(+), 19 deletions(-)

diff --git a/go.mod b/go.mod
index 98f69b5a..66ae78b8 100644
--- a/go.mod
+++ b/go.mod
@@ -9,7 +9,7 @@ require (
 	github.com/aler9/writerseeker v1.1.0
 	github.com/bluenviron/gohlslib v1.0.3
 	github.com/bluenviron/gortsplib/v4 v4.2.0
-	github.com/bluenviron/mediacommon v1.4.1-0.20231007133411-92ec4e147f89
+	github.com/bluenviron/mediacommon v1.4.1-0.20231007152904-4c7d799a3253
 	github.com/datarhei/gosrt v0.5.4
 	github.com/fsnotify/fsnotify v1.6.0
 	github.com/gin-gonic/gin v1.9.1
diff --git a/go.sum b/go.sum
index b30e6fc1..81d7a437 100644
--- a/go.sum
+++ b/go.sum
@@ -16,8 +16,8 @@ github.com/bluenviron/gohlslib v1.0.3 h1:FMHevlIrrZ67uzCXmlTSGflsfYREEtHb8L9BDyf
 github.com/bluenviron/gohlslib v1.0.3/go.mod h1:R/aIsSxLI61N0CVMjtcHqJouK6+Ddd5YIihcCr7IFIw=
 github.com/bluenviron/gortsplib/v4 v4.2.0 h1:EbIMqkFxFo/iG5Hkld+Flew9R8ORKnuxlgUyFdpd5Rk=
 github.com/bluenviron/gortsplib/v4 v4.2.0/go.mod h1:wz9d4Tn2qS/mexc+BnvNeWzlNOpyaHzNK6SXxtg4mfM=
-github.com/bluenviron/mediacommon v1.4.1-0.20231007133411-92ec4e147f89 h1:IEicF/CpzU78BJ95v0XwTWL5D2Kr2grlpe5jnuhbRN8=
-github.com/bluenviron/mediacommon v1.4.1-0.20231007133411-92ec4e147f89/go.mod h1:Ij/kE1LEucSjryNBVTyPL/gBI0d6/Css3f5PyrM957w=
+github.com/bluenviron/mediacommon v1.4.1-0.20231007152904-4c7d799a3253 h1:r98CMlefqn1U/mYHifWD9Udb52E8axvjUkv70FJV2qQ=
+github.com/bluenviron/mediacommon v1.4.1-0.20231007152904-4c7d799a3253/go.mod h1:Ij/kE1LEucSjryNBVTyPL/gBI0d6/Css3f5PyrM957w=
 github.com/bytedance/sonic v1.5.0/go.mod h1:ED5hyg4y6t3/9Ku1R6dU/4KyJ48DZ4jPhfY1O2AihPM=
 github.com/bytedance/sonic v1.9.1 h1:6iJ6NqdoxCDr6mbY8h18oSO+cShGSMRGCEo7F2h0x8s=
 github.com/bytedance/sonic v1.9.1/go.mod h1:i736AoUSYt75HyZLoJW9ERYxcy6eaN6h4BZXU064P/U=
diff --git a/internal/record/agent.go b/internal/record/agent.go
index baaa637a..5ce1c2e3 100644
--- a/internal/record/agent.go
+++ b/internal/record/agent.go
@@ -114,12 +114,13 @@ type Agent struct {
 	onSegmentComplete func(string)
 	parent            logger.Writer
 
-	ctx            context.Context
-	ctxCancel      func()
-	writer         *asyncwriter.Writer
-	tracks         []*track
-	hasVideo       bool
-	currentSegment *segment
+	ctx                context.Context
+	ctxCancel          func()
+	writer             *asyncwriter.Writer
+	tracks             []*track
+	hasVideo           bool
+	currentSegment     *segment
+	nextSequenceNumber uint32
 
 	done chan struct{}
 }
diff --git a/internal/record/part.go b/internal/record/part.go
index a9dd6ec5..32b7e9fd 100644
--- a/internal/record/part.go
+++ b/internal/record/part.go
@@ -12,7 +12,7 @@ import (
 	"github.com/bluenviron/mediamtx/internal/logger"
 )
 
-func writePart(f io.Writer, partTracks map[*track]*fmp4.PartTrack) error {
+func writePart(f io.Writer, sequenceNumber uint32, partTracks map[*track]*fmp4.PartTrack) error {
 	fmp4PartTracks := make([]*fmp4.PartTrack, len(partTracks))
 	i := 0
 	for _, partTrack := range partTracks {
@@ -21,7 +21,8 @@ func writePart(f io.Writer, partTracks map[*track]*fmp4.PartTrack) error {
 	}
 
 	part := &fmp4.Part{
-		Tracks: fmp4PartTracks,
+		SequenceNumber: sequenceNumber,
+		Tracks:         fmp4PartTracks,
 	}
 
 	var ws writerseeker.WriterSeeker
@@ -35,8 +36,9 @@ func writePart(f io.Writer, partTracks map[*track]*fmp4.PartTrack) error {
 }
 
 type part struct {
-	s        *segment
-	startDTS time.Duration
+	s              *segment
+	sequenceNumber uint32
+	startDTS       time.Duration
 
 	partTracks map[*track]*fmp4.PartTrack
 	endDTS     time.Duration
@@ -44,12 +46,14 @@ type part struct {
 
 func newPart(
 	s *segment,
+	sequenceNumber uint32,
 	startDTS time.Duration,
 ) *part {
 	return &part{
-		s:          s,
-		startDTS:   startDTS,
-		partTracks: make(map[*track]*fmp4.PartTrack),
+		s:              s,
+		startDTS:       startDTS,
+		sequenceNumber: sequenceNumber,
+		partTracks:     make(map[*track]*fmp4.PartTrack),
 	}
 }
 
@@ -77,7 +81,7 @@ func (p *part) close() error {
 		p.s.f = f
 	}
 
-	return writePart(p.s.f, p.partTracks)
+	return writePart(p.s.f, p.sequenceNumber, p.partTracks)
 }
 
 func (p *part) record(track *track, sample *sample) error {
diff --git a/internal/record/segment.go b/internal/record/segment.go
index 06c527ed..224a1471 100644
--- a/internal/record/segment.go
+++ b/internal/record/segment.go
@@ -76,7 +76,8 @@ func (s *segment) close() error {
 
 func (s *segment) record(track *track, sample *sample) error {
 	if s.curPart == nil {
-		s.curPart = newPart(s, sample.dts)
+		s.curPart = newPart(s, s.r.nextSequenceNumber, sample.dts)
+		s.r.nextSequenceNumber++
 	} else if s.curPart.duration() >= s.r.partDuration {
 		err := s.curPart.close()
 		s.curPart = nil
@@ -85,7 +86,8 @@ func (s *segment) record(track *track, sample *sample) error {
 			return err
 		}
 
-		s.curPart = newPart(s, sample.dts)
+		s.curPart = newPart(s, s.r.nextSequenceNumber, sample.dts)
+		s.r.nextSequenceNumber++
 	}
 
 	return s.curPart.record(track, sample)