muxer: prepend prefix to segments

This is needed to prevent usage of cached segments from previous muxing
sessions

muxer.go

@@ -2,6 +2,8 @@ package gohlslib
 
 import (
 	"bytes"
+	"crypto/rand"
+	"encoding/hex"
 	"fmt"
 	"net/http"
 	"time"
@@ -14,6 +16,18 @@ import (
 	"github.com/bluenviron/gohlslib/pkg/storage"
 )
 
+// a prefix is needed to prevent usage of cached segments
+// from previous muxing sessions.
+func generatePrefix() (string, error) {
+	var buf [6]byte
+	_, err := rand.Read(buf[:])
+	if err != nil {
+		return "", err
+	}
+
+	return hex.EncodeToString(buf[:]), nil
+}
+
 // MuxerVariant is a muxer variant.
 type MuxerVariant int
 
@@ -68,6 +82,7 @@ type Muxer struct {
 	// private
 	//
 
+	prefix         string
 	storageFactory storage.Factory
 	server         *muxerServer
 	segmenter      muxerSegmenter
@@ -120,18 +135,24 @@ func (m *Muxer) Start() error {
 		}
 	}
 
+	var err error
+	m.prefix, err = generatePrefix()
+	if err != nil {
+		return err
+	}
+
 	if m.Directory != "" {
 		m.storageFactory = storage.NewFactoryDisk(m.Directory)
 	} else {
 		m.storageFactory = storage.NewFactoryRAM()
 	}
 
-	var err error
 	m.server, err = newMuxerServer(
 		m.Variant,
 		m.SegmentCount,
 		m.VideoTrack,
 		m.AudioTrack,
+		m.prefix,
 		m.storageFactory,
 	)
 	if err != nil {
@@ -144,8 +165,9 @@ func (m *Muxer) Start() error {
 			m.SegmentMaxSize,
 			m.VideoTrack,
 			m.AudioTrack,
+			m.prefix,
 			m.storageFactory,
-			m.server.onSegmentFinalized,
+			m.server.publishSegment,
 		)
 	} else {
 		m.segmenter = newMuxerSegmenterFMP4(
@@ -155,9 +177,10 @@ func (m *Muxer) Start() error {
 			m.SegmentMaxSize,
 			m.VideoTrack,
 			m.AudioTrack,
+			m.prefix,
 			m.storageFactory,
-			m.server.onSegmentFinalized,
-			m.server.onPartFinalized,
+			m.server.publishSegment,
+			m.server.publishPart,
 		)
 	}
 

muxer_part.go

@@ -9,8 +9,8 @@ import (
 	"github.com/bluenviron/mediacommon/pkg/formats/fmp4"
 )
 
-func fmp4PartName(id uint64) string {
-	return "part" + strconv.FormatUint(id, 10)
+func partName(prefix string, id uint64) string {
+	return prefix + "_part" + strconv.FormatUint(id, 10) + ".mp4"
 }
 
 type muxerPart struct {
@@ -21,6 +21,7 @@ type muxerPart struct {
 	id                  uint64
 	storage             storage.Part
 
+	name                string
 	isIndependent       bool
 	videoSamples        []*fmp4.PartSample
 	audioSamples        []*fmp4.PartSample
@@ -36,6 +37,7 @@ func newMuxerPart(
 	videoTrack *Track,
 	audioTrack *Track,
 	audioTrackTimeScale uint32,
+	prefix string,
 	id uint64,
 	storage storage.Part,
 ) *muxerPart {
@@ -46,6 +48,7 @@ func newMuxerPart(
 		audioTrackTimeScale: audioTrackTimeScale,
 		id:                  id,
 		storage:             storage,
+		name:                partName(prefix, id),
 	}
 
 	if videoTrack == nil {
@@ -55,8 +58,8 @@ func newMuxerPart(
 	return p
 }
 
-func (p *muxerPart) name() string {
-	return fmp4PartName(p.id)
+func (p *muxerPart) getName() string {
+	return p.name
 }
 
 func (p *muxerPart) reader() (io.ReadCloser, error) {

muxer_segment.go

@@ -3,9 +3,17 @@ package gohlslib
 import (
 	"fmt"
 	"io"
+	"strconv"
 	"time"
 )
 
+func segmentName(prefix string, id uint64, mp4 bool) string {
+	if mp4 {
+		return prefix + "_seg" + strconv.FormatUint(id, 10) + ".mp4"
+	}
+	return prefix + "_seg" + strconv.FormatUint(id, 10) + ".ts"
+}
+
 type muxerSegment interface {
 	close()
 	getName() string

muxer_segment_fmp4.go

@@ -3,7 +3,6 @@ package gohlslib
 import (
 	"fmt"
 	"io"
-	"strconv"
 	"time"
 
 	"github.com/bluenviron/gohlslib/pkg/storage"
@@ -18,8 +17,9 @@ type muxerSegmentFMP4 struct {
 	videoTrack          *Track
 	audioTrack          *Track
 	audioTrackTimeScale uint32
+	prefix              string
 	genPartID           func() uint64
-	onPartFinalized     func(*muxerPart)
+	publishPart         func(*muxerPart)
 
 	name        string
 	storage     storage.File
@@ -38,9 +38,10 @@ func newMuxerSegmentFMP4(
 	videoTrack *Track,
 	audioTrack *Track,
 	audioTrackTimeScale uint32,
+	prefix string,
 	factory storage.Factory,
 	genPartID func() uint64,
-	onPartFinalized func(*muxerPart),
+	publishPart func(*muxerPart),
 ) (*muxerSegmentFMP4, error) {
 	s := &muxerSegmentFMP4{
 		lowLatency:          lowLatency,
@@ -51,13 +52,14 @@ func newMuxerSegmentFMP4(
 		videoTrack:          videoTrack,
 		audioTrack:          audioTrack,
 		audioTrackTimeScale: audioTrackTimeScale,
+		prefix:              prefix,
 		genPartID:           genPartID,
-		onPartFinalized:     onPartFinalized,
-		name:                "seg" + strconv.FormatUint(id, 10),
+		publishPart:         publishPart,
+		name:                segmentName(prefix, id, true),
 	}
 
 	var err error
-	s.storage, err = factory.NewFile(s.name + ".mp4")
+	s.storage, err = factory.NewFile(s.name)
 	if err != nil {
 		return nil, err
 	}
@@ -67,6 +69,7 @@ func newMuxerSegmentFMP4(
 		s.videoTrack,
 		s.audioTrack,
 		s.audioTrackTimeScale,
+		prefix,
 		s.genPartID(),
 		s.storage.NewPart(),
 	)
@@ -101,7 +104,7 @@ func (s *muxerSegmentFMP4) finalize(nextDTS time.Duration) error {
 			return err
 		}
 
-		s.onPartFinalized(s.currentPart)
+		s.publishPart(s.currentPart)
 		s.parts = append(s.parts, s.currentPart)
 	}
 	s.currentPart = nil
@@ -135,13 +138,14 @@ func (s *muxerSegmentFMP4) writeVideo(
 		}
 
 		s.parts = append(s.parts, s.currentPart)
-		s.onPartFinalized(s.currentPart)
+		s.publishPart(s.currentPart)
 
 		s.currentPart = newMuxerPart(
 			nextDTS,
 			s.videoTrack,
 			s.audioTrack,
 			s.audioTrackTimeScale,
+			s.prefix,
 			s.genPartID(),
 			s.storage.NewPart(),
 		)
@@ -172,13 +176,14 @@ func (s *muxerSegmentFMP4) writeAudio(
 		}
 
 		s.parts = append(s.parts, s.currentPart)
-		s.onPartFinalized(s.currentPart)
+		s.publishPart(s.currentPart)
 
 		s.currentPart = newMuxerPart(
 			nextAudioSampleDTS,
 			s.videoTrack,
 			s.audioTrack,
 			s.audioTrackTimeScale,
+			s.prefix,
 			s.genPartID(),
 			s.storage.NewPart(),
 		)

muxer_segment_mpegts.go

@@ -4,7 +4,6 @@ import (
 	"bufio"
 	"fmt"
 	"io"
-	"strconv"
 	"time"
 
 	"github.com/bluenviron/gohlslib/pkg/storage"
@@ -42,6 +41,7 @@ func newMuxerSegmentMPEGTS(
 	writerAudioTrack *mpegts.Track,
 	switchableWriter *switchableWriter,
 	writer *mpegts.Writer,
+	prefix string,
 	factory storage.Factory,
 ) (*muxerSegmentMPEGTS, error) {
 	t := &muxerSegmentMPEGTS{
@@ -50,11 +50,11 @@ func newMuxerSegmentMPEGTS(
 		writerAudioTrack: writerAudioTrack,
 		writer:           writer,
 		startNTP:         startNTP,
-		name:             "seg" + strconv.FormatUint(id, 10),
+		name:             segmentName(prefix, id, false),
 	}
 
 	var err error
-	t.storage, err = factory.NewFile(t.name + ".ts")
+	t.storage, err = factory.NewFile(t.name)
 	if err != nil {
 		return nil, err
 	}