diff --git a/pkg/formats/mpegts/reader_test.go b/pkg/formats/mpegts/reader_test.go
index 373be37..936679d 100644
--- a/pkg/formats/mpegts/reader_test.go
+++ b/pkg/formats/mpegts/reader_test.go
@@ -10,6 +10,7 @@ import (
 	"github.com/asticode/go-astits"
 	"github.com/stretchr/testify/require"
 
+	"github.com/bluenviron/mediacommon/pkg/codecs/h264"
 	"github.com/bluenviron/mediacommon/pkg/codecs/h265"
 	"github.com/bluenviron/mediacommon/pkg/codecs/mpeg4audio"
 )
@@ -59,6 +60,7 @@ var casesReadWriter = []struct {
 				30 * 90000,
 				30 * 90000,
 				[][]byte{
+					{byte(h265.NALUType_AUD_NUT) << 1, 1, 0x50}, // AUD
 					testH265SPS, // SPS
 					testH265PPS, // PPS
 					{byte(h265.NALUType_CRA_NUT) << 1},
@@ -68,6 +70,7 @@ var casesReadWriter = []struct {
 				30*90000 + 2*90000,
 				30*90000 + 1*90000,
 				[][]byte{
+					{byte(h265.NALUType_AUD_NUT) << 1, 1, 0x50}, // AUD
 					{byte(h265.NALUType_TRAIL_N) << 1},
 				},
 			},
@@ -99,8 +102,8 @@ var casesReadWriter = []struct {
 			},
 			{ // PES
 				AdaptationField: &astits.PacketAdaptationField{
-					Length:                88,
-					StuffingLength:        81,
+					Length:                81,
+					StuffingLength:        74,
 					RandomAccessIndicator: true,
 					HasPCR:                true,
 					PCR:                   &astits.ClockReference{Base: 2691000},
@@ -114,22 +117,23 @@ var casesReadWriter = []struct {
 				Payload: []byte{
 					0x00, 0x00, 0x01, 0xe0, 0x00, 0x00, 0x80, 0x80,
 					0x05, 0x21, 0x00, 0xa5, 0x65, 0xc1, 0x00, 0x00,
-					0x00, 0x01, 0x42, 0x01, 0x01, 0x02, 0x20, 0x00,
-					0x00, 0x03, 0x00, 0xb0, 0x00, 0x00, 0x03, 0x00,
-					0x00, 0x03, 0x00, 0x7b, 0xa0, 0x07, 0x82, 0x00,
-					0x88, 0x7d, 0xb6, 0x71, 0x8b, 0x92, 0x44, 0x80,
-					0x53, 0x88, 0x88, 0x92, 0xcf, 0x24, 0xa6, 0x92,
-					0x72, 0xc9, 0x12, 0x49, 0x22, 0xdc, 0x91, 0xaa,
-					0x48, 0xfc, 0xa2, 0x23, 0xff, 0x00, 0x01, 0x00,
-					0x01, 0x6a, 0x02, 0x02, 0x02, 0x01, 0x00, 0x00,
-					0x00, 0x01, 0x44, 0x01, 0xc0, 0x25, 0x2f, 0x05,
-					0x32, 0x40, 0x00, 0x00, 0x00, 0x01, 0x2a,
+					0x00, 0x01, 0x46, 0x01, 0x50, 0x00, 0x00, 0x00,
+					0x01, 0x42, 0x01, 0x01, 0x02, 0x20, 0x00, 0x00,
+					0x03, 0x00, 0xb0, 0x00, 0x00, 0x03, 0x00, 0x00,
+					0x03, 0x00, 0x7b, 0xa0, 0x07, 0x82, 0x00, 0x88,
+					0x7d, 0xb6, 0x71, 0x8b, 0x92, 0x44, 0x80, 0x53,
+					0x88, 0x88, 0x92, 0xcf, 0x24, 0xa6, 0x92, 0x72,
+					0xc9, 0x12, 0x49, 0x22, 0xdc, 0x91, 0xaa, 0x48,
+					0xfc, 0xa2, 0x23, 0xff, 0x00, 0x01, 0x00, 0x01,
+					0x6a, 0x02, 0x02, 0x02, 0x01, 0x00, 0x00, 0x00,
+					0x01, 0x44, 0x01, 0xc0, 0x25, 0x2f, 0x05, 0x32,
+					0x40, 0x00, 0x00, 0x00, 0x01, 0x2a,
 				},
 			},
 			{ // PES
 				AdaptationField: &astits.PacketAdaptationField{
-					Length:         159,
-					StuffingLength: 158,
+					Length:         152,
+					StuffingLength: 151,
 				},
 				Header: astits.PacketHeader{
 					ContinuityCounter:         1,
@@ -141,7 +145,8 @@ var casesReadWriter = []struct {
 				Payload: []byte{
 					0x00, 0x00, 0x01, 0xe0, 0x00, 0x00, 0x80, 0xc0,
 					0x0a, 0x31, 0x00, 0xaf, 0xe4, 0x01, 0x11, 0x00,
-					0xab, 0x24, 0xe1, 0x00, 0x00, 0x00, 0x01, 0x00,
+					0xab, 0x24, 0xe1, 0x00, 0x00, 0x00, 0x01, 0x46,
+					0x01, 0x50, 0x00, 0x00, 0x00, 0x01, 0x00,
 				},
 			},
 		},
@@ -157,6 +162,7 @@ var casesReadWriter = []struct {
 				30 * 90000,
 				30 * 90000,
 				[][]byte{
+					{byte(h264.NALUTypeAccessUnitDelimiter), 240}, // AUD
 					testH264SPS, // SPS
 					{8},         // PPS
 					{5},         // IDR
@@ -166,6 +172,7 @@ var casesReadWriter = []struct {
 				30*90000 + 2*90000,
 				30*90000 + 1*90000,
 				[][]byte{
+					{byte(h264.NALUTypeAccessUnitDelimiter), 240}, // AUD
 					{1}, // non-IDR
 				},
 			},
@@ -197,8 +204,8 @@ var casesReadWriter = []struct {
 			},
 			{ // PES
 				AdaptationField: &astits.PacketAdaptationField{
-					Length:                130,
-					StuffingLength:        123,
+					Length:                124,
+					StuffingLength:        117,
 					RandomAccessIndicator: true,
 					HasPCR:                true,
 					PCR:                   &astits.ClockReference{Base: 2691000},
@@ -212,17 +219,18 @@ var casesReadWriter = []struct {
 				Payload: []byte{
 					0x00, 0x00, 0x01, 0xe0, 0x00, 0x00, 0x80, 0x80,
 					0x05, 0x21, 0x00, 0xa5, 0x65, 0xc1, 0x00, 0x00,
-					0x00, 0x01, 0x67, 0x42, 0xc0, 0x28, 0xd9, 0x00,
-					0x78, 0x02, 0x27, 0xe5, 0x84, 0x00, 0x00, 0x03,
-					0x00, 0x04, 0x00, 0x00, 0x03, 0x00, 0xf0, 0x3c,
-					0x60, 0xc9, 0x20, 0x00, 0x00, 0x00, 0x01, 0x08,
-					0x00, 0x00, 0x00, 0x01, 0x05,
+					0x00, 0x01, 0x09, 0xf0, 0x00, 0x00, 0x00, 0x01,
+					0x67, 0x42, 0xc0, 0x28, 0xd9, 0x00, 0x78, 0x02,
+					0x27, 0xe5, 0x84, 0x00, 0x00, 0x03, 0x00, 0x04,
+					0x00, 0x00, 0x03, 0x00, 0xf0, 0x3c, 0x60, 0xc9,
+					0x20, 0x00, 0x00, 0x00, 0x01, 0x08, 0x00, 0x00,
+					0x00, 0x01, 0x05,
 				},
 			},
 			{ // PES
 				AdaptationField: &astits.PacketAdaptationField{
-					Length:         159,
-					StuffingLength: 158,
+					Length:         153,
+					StuffingLength: 152,
 				},
 				Header: astits.PacketHeader{
 					ContinuityCounter:         1,
@@ -234,7 +242,8 @@ var casesReadWriter = []struct {
 				Payload: []byte{
 					0x00, 0x00, 0x01, 0xe0, 0x00, 0x00, 0x80, 0xc0,
 					0x0a, 0x31, 0x00, 0xaf, 0xe4, 0x01, 0x11, 0x00,
-					0xab, 0x24, 0xe1, 0x00, 0x00, 0x00, 0x01, 0x01,
+					0xab, 0x24, 0xe1, 0x00, 0x00, 0x00, 0x01, 0x09,
+					0xf0, 0x00, 0x00, 0x00, 0x01, 0x01,
 				},
 			},
 		},
diff --git a/pkg/formats/mpegts/writer.go b/pkg/formats/mpegts/writer.go
index 7e4a0d9..41db8ed 100644
--- a/pkg/formats/mpegts/writer.go
+++ b/pkg/formats/mpegts/writer.go
@@ -9,6 +9,7 @@ import (
 	"github.com/asticode/go-astits"
 
 	"github.com/bluenviron/mediacommon/pkg/codecs/h264"
+	"github.com/bluenviron/mediacommon/pkg/codecs/h265"
 	"github.com/bluenviron/mediacommon/pkg/codecs/mpeg1audio"
 	"github.com/bluenviron/mediacommon/pkg/codecs/mpeg4audio"
 	"github.com/bluenviron/mediacommon/pkg/codecs/mpeg4video"
@@ -89,6 +90,8 @@ func NewWriter(
 }
 
 // WriteH26x writes a H26x access unit.
+//
+// Deprecated: replaced by WriteH264 and WriteH265.
 func (w *Writer) WriteH26x(
 	track *Track,
 	pts int64,
@@ -96,6 +99,50 @@ func (w *Writer) WriteH26x(
 	randomAccess bool,
 	au [][]byte,
 ) error {
+	if _, ok := track.Codec.(*CodecH265); ok {
+		return w.WriteH265(track, pts, dts, randomAccess, au)
+	}
+	return w.WriteH264(track, pts, dts, randomAccess, au)
+}
+
+// WriteH264 writes a H264 access unit.
+func (w *Writer) WriteH264(
+	track *Track,
+	pts int64,
+	dts int64,
+	randomAccess bool,
+	au [][]byte,
+) error {
+	// prepend an AUD. This is required by video.js, iOS, QuickTime
+	if h264.NALUType(au[0][0]&0x1F) != h264.NALUTypeAccessUnitDelimiter {
+		au = append([][]byte{
+			{byte(h264.NALUTypeAccessUnitDelimiter), 240},
+		}, au...)
+	}
+
+	enc, err := h264.AnnexBMarshal(au)
+	if err != nil {
+		return err
+	}
+
+	return w.writeVideo(track, pts, dts, randomAccess, enc)
+}
+
+// WriteH265 writes a H265 access unit.
+func (w *Writer) WriteH265(
+	track *Track,
+	pts int64,
+	dts int64,
+	randomAccess bool,
+	au [][]byte,
+) error {
+	// prepend an AUD. This is required by video.js, iOS, QuickTime
+	if h265.NALUType(au[0][0]>>1) != h265.NALUType_AUD_NUT {
+		au = append([][]byte{
+			{byte(h265.NALUType_AUD_NUT) << 1, 1, 0x50},
+		}, au...)
+	}
+
 	enc, err := h264.AnnexBMarshal(au)
 	if err != nil {
 		return err