playback: support serving tracks with any time scale

internal/playback/muxer.go

@@ -1,7 +1,9 @@
 package playback
 
+import "github.com/bluenviron/mediacommon/pkg/formats/fmp4"
+
 type muxer interface {
-	writeInit(init []byte)
+	writeInit(init *fmp4.Init)
 	setTrack(trackID int)
 	writeSample(dts int64, ptsOffset int32, isNonSyncSample bool, payload []byte) error
 	writeFinalDTS(dts int64)

internal/playback/muxer_fmp4.go

@@ -8,13 +8,16 @@ import (
 	"github.com/bluenviron/mediacommon/pkg/formats/fmp4/seekablebuffer"
 )
 
-var partSize = durationGoToMp4(1*time.Second, fmp4Timescale)
+const (
+	partSize = 1 * time.Second
+)
 
 type muxerFMP4Track struct {
-	id       int
-	firstDTS int64
-	lastDTS  int64
-	samples  []*fmp4.PartSample
+	id        int
+	timeScale uint32
+	firstDTS  int64
+	lastDTS   int64
+	samples   []*fmp4.PartSample
 }
 
 func findTrack(tracks []*muxerFMP4Track, id int) *muxerFMP4Track {
@@ -29,26 +32,29 @@ func findTrack(tracks []*muxerFMP4Track, id int) *muxerFMP4Track {
 type muxerFMP4 struct {
 	w io.Writer
 
-	init               []byte
+	init               *fmp4.Init
 	nextSequenceNumber uint32
 	tracks             []*muxerFMP4Track
 	curTrack           *muxerFMP4Track
 	outBuf             seekablebuffer.Buffer
 }
 
-func (w *muxerFMP4) writeInit(init []byte) {
+func (w *muxerFMP4) writeInit(init *fmp4.Init) {
 	w.init = init
+
+	w.tracks = make([]*muxerFMP4Track, len(init.Tracks))
+
+	for i, track := range init.Tracks {
+		w.tracks[i] = &muxerFMP4Track{
+			id:        track.ID,
+			timeScale: track.TimeScale,
+			firstDTS:  -1,
+		}
+	}
 }
 
 func (w *muxerFMP4) setTrack(trackID int) {
 	w.curTrack = findTrack(w.tracks, trackID)
-	if w.curTrack == nil {
-		w.curTrack = &muxerFMP4Track{
-			id:       trackID,
-			firstDTS: -1,
-		}
-		w.tracks = append(w.tracks, w.curTrack)
-	}
 }
 
 func (w *muxerFMP4) writeSample(dts int64, ptsOffset int32, isNonSyncSample bool, payload []byte) error {
@@ -75,7 +81,9 @@ func (w *muxerFMP4) writeSample(dts int64, ptsOffset int32, isNonSyncSample bool
 		})
 		w.curTrack.lastDTS = dts
 
-		if (w.curTrack.lastDTS - w.curTrack.firstDTS) > int64(partSize) {
+		partSizeMP4 := durationGoToMp4(partSize, w.curTrack.timeScale)
+
+		if (w.curTrack.lastDTS - w.curTrack.firstDTS) > partSizeMP4 {
 			err := w.innerFlush(false)
 			if err != nil {
 				return err
@@ -141,11 +149,18 @@ func (w *muxerFMP4) innerFlush(final bool) error {
 		w.nextSequenceNumber++
 
 		if w.init != nil {
-			_, err := w.w.Write(w.init)
+			err := w.init.Marshal(&w.outBuf)
+			if err != nil {
+				return err
+			}
+
+			_, err = w.w.Write(w.outBuf.Bytes())
 			if err != nil {
 				return err
 			}
+
 			w.init = nil
+			w.outBuf.Reset()
 		}
 
 		err := part.Marshal(&w.outBuf)

internal/playback/on_get.go

@@ -9,6 +9,7 @@ import (
 	"strconv"
 	"time"
 
+	"github.com/bluenviron/mediacommon/pkg/formats/fmp4"
 	"github.com/bluenviron/mediamtx/internal/conf"
 	"github.com/bluenviron/mediamtx/internal/logger"
 	"github.com/gin-gonic/gin"
@@ -48,7 +49,7 @@ func seekAndMux(
 	m muxer,
 ) error {
 	if recordFormat == conf.RecordFormatFMP4 {
-		var firstInit []byte
+		var firstInit *fmp4.Init
 		var segmentEnd time.Time
 
 		err := func() error {
@@ -67,7 +68,7 @@ func seekAndMux(
 
 			segmentStartOffset := start.Sub(segments[0].Start)
 
-			segmentMaxElapsed, err := segmentFMP4SeekAndMuxParts(f, segmentStartOffset, duration, m)
+			segmentMaxElapsed, err := segmentFMP4SeekAndMuxParts(f, segmentStartOffset, duration, firstInit, m)
 			if err != nil {
 				return err
 			}
@@ -99,7 +100,7 @@ func seekAndMux(
 
 				segmentStartOffset := seg.Start.Sub(start)
 
-				segmentMaxElapsed, err := segmentFMP4WriteParts(f, segmentStartOffset, duration, m)
+				segmentMaxElapsed, err := segmentFMP4WriteParts(f, segmentStartOffset, duration, firstInit, m)
 				if err != nil {
 					return err
 				}

internal/playback/on_list.go

@@ -9,6 +9,7 @@ import (
 	"os"
 	"time"
 
+	"github.com/bluenviron/mediacommon/pkg/formats/fmp4"
 	"github.com/bluenviron/mediamtx/internal/conf"
 	"github.com/gin-gonic/gin"
 )
@@ -27,7 +28,7 @@ type listEntry struct {
 func computeDurationAndConcatenate(recordFormat conf.RecordFormat, segments []*Segment) ([]listEntry, error) {
 	if recordFormat == conf.RecordFormatFMP4 {
 		out := []listEntry{}
-		var prevInit []byte
+		var prevInit *fmp4.Init
 
 		for _, seg := range segments {
 			err := func() error {
@@ -47,7 +48,7 @@ func computeDurationAndConcatenate(recordFormat conf.RecordFormat, segments []*S
 					return err
 				}
 
-				maxDuration, err := segmentFMP4ReadMaxDuration(f)
+				maxDuration, err := segmentFMP4ReadMaxDuration(f, init)
 				if err != nil {
 					return err
 				}