diff --git a/internal/hls/fmp4/part.go b/internal/hls/fmp4/part.go
index 7ff3de59..d82facdf 100644
--- a/internal/hls/fmp4/part.go
+++ b/internal/hls/fmp4/part.go
@@ -6,6 +6,7 @@ import (
 
 	gomp4 "github.com/abema/go-mp4"
 	"github.com/aler9/gortsplib"
+	"github.com/aler9/gortsplib/pkg/h264"
 )
 
 func durationGoToMp4(v time.Duration, timescale time.Duration) int64 {
@@ -77,7 +78,7 @@ func generatePartVideoTraf(
 
 		trun.Entries = append(trun.Entries, gomp4.TrunEntry{
 			SampleDuration:                uint32(durationGoToMp4(e.Duration(), videoTimescale)),
-			SampleSize:                    uint32(len(e.AVCC)),
+			SampleSize:                    uint32(len(e.avcc)),
 			SampleFlags:                   flags,
 			SampleCompositionTimeOffsetV1: int32(durationGoToMp4(off, videoTimescale)),
 		})
@@ -208,6 +209,14 @@ func GeneratePart(
 	var videoTrun *gomp4.Trun
 	var videoTrunOffset int
 	if videoTrack != nil {
+		for _, e := range videoSamples {
+			var err error
+			e.avcc, err = h264.AVCCMarshal(e.NALUs)
+			if err != nil {
+				return nil, err
+			}
+		}
+
 		var err error
 		videoTrun, videoTrunOffset, err = generatePartVideoTraf(
 			w, trackID, videoSamples)
@@ -240,7 +249,7 @@ func GeneratePart(
 
 	if videoTrack != nil {
 		for _, e := range videoSamples {
-			dataSize += len(e.AVCC)
+			dataSize += len(e.avcc)
 		}
 		videoDataSize = dataSize
 	}
@@ -256,7 +265,7 @@ func GeneratePart(
 
 	if videoTrack != nil {
 		for _, e := range videoSamples {
-			pos += copy(mdat.Data[pos:], e.AVCC)
+			pos += copy(mdat.Data[pos:], e.avcc)
 		}
 	}
 
diff --git a/internal/hls/fmp4/videosample.go b/internal/hls/fmp4/videosample.go
index a28e0205..4f7416da 100644
--- a/internal/hls/fmp4/videosample.go
+++ b/internal/hls/fmp4/videosample.go
@@ -13,9 +13,10 @@ type VideoSample struct {
 	NALUs      [][]byte
 	PTS        time.Duration
 	DTS        time.Duration
-	AVCC       []byte
 	IDRPresent bool
 	Next       *VideoSample
+
+	avcc []byte
 }
 
 // Duration returns the sample duration.
diff --git a/internal/hls/muxer_variant_fmp4_segment.go b/internal/hls/muxer_variant_fmp4_segment.go
index c53baa63..ebfa8569 100644
--- a/internal/hls/muxer_variant_fmp4_segment.go
+++ b/internal/hls/muxer_variant_fmp4_segment.go
@@ -131,16 +131,17 @@ func (s *muxerVariantFMP4Segment) finalize(
 }
 
 func (s *muxerVariantFMP4Segment) writeH264(sample *fmp4.VideoSample, adjustedPartDuration time.Duration) error {
-	size := uint64(len(sample.AVCC))
-
+	size := uint64(0)
+	for _, nalu := range sample.NALUs {
+		size += uint64(len(nalu))
+	}
 	if (s.size + size) > s.segmentMaxSize {
 		return fmt.Errorf("reached maximum segment size")
 	}
+	s.size += size
 
 	s.currentPart.writeH264(sample)
 
-	s.size += size
-
 	// switch part
 	if s.lowLatency &&
 		s.currentPart.duration() >= adjustedPartDuration {
@@ -164,15 +165,13 @@ func (s *muxerVariantFMP4Segment) writeH264(sample *fmp4.VideoSample, adjustedPa
 
 func (s *muxerVariantFMP4Segment) writeAAC(sample *fmp4.AudioSample, adjustedPartDuration time.Duration) error {
 	size := uint64(len(sample.AU))
-
 	if (s.size + size) > s.segmentMaxSize {
 		return fmt.Errorf("reached maximum segment size")
 	}
+	s.size += size
 
 	s.currentPart.writeAAC(sample)
 
-	s.size += size
-
 	// switch part
 	if s.lowLatency && s.videoTrack == nil &&
 		s.currentPart.duration() >= adjustedPartDuration {
diff --git a/internal/hls/muxer_variant_fmp4_segmenter.go b/internal/hls/muxer_variant_fmp4_segmenter.go
index a241ba76..4f809f46 100644
--- a/internal/hls/muxer_variant_fmp4_segmenter.go
+++ b/internal/hls/muxer_variant_fmp4_segmenter.go
@@ -141,15 +141,9 @@ func (m *muxerVariantFMP4Segmenter) writeH264(pts time.Duration, nalus [][]byte)
 		return nil
 	}
 
-	avcc, err := h264.AVCCMarshal(nalus)
-	if err != nil {
-		return err
-	}
-
 	return m.writeH264Entry(&fmp4.VideoSample{
 		PTS:        pts,
 		NALUs:      nalus,
-		AVCC:       avcc,
 		IDRPresent: idrPresent,
 	})
 }