diff --git a/box_types_3gpp.go b/box_types_3gpp.go
new file mode 100644
index 0000000..d19640c
--- /dev/null
+++ b/box_types_3gpp.go
@@ -0,0 +1,24 @@
+package mp4
+
+var udta3GppMetaBoxTypes = []BoxType{
+	StrToBoxType("titl"),
+	StrToBoxType("dscp"),
+	StrToBoxType("cprt"),
+	StrToBoxType("perf"),
+	StrToBoxType("auth"),
+	StrToBoxType("gnre"),
+}
+
+func init() {
+	for _, bt := range udta3GppMetaBoxTypes {
+		AddAnyTypeBoxDefEx(&Udta3GppString{}, bt, isUnderUdta, 0)
+	}
+}
+
+type Udta3GppString struct {
+	AnyTypeBox
+	FullBox  `mp4:"0,extend"`
+	Pad      bool    `mp4:"1,size=1,hidden"`
+	Language [3]byte `mp4:"2,size=5,iso639-2"` // ISO-639-2/T language code
+	Data     []byte  `mp4:"3,size=8,string"`
+}
diff --git a/box_types_3gpp_test.go b/box_types_3gpp_test.go
new file mode 100644
index 0000000..783ede9
--- /dev/null
+++ b/box_types_3gpp_test.go
@@ -0,0 +1,75 @@
+package mp4
+
+import (
+	"bytes"
+	"io"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestBoxTypes3GPP(t *testing.T) {
+	testCases := []struct {
+		name string
+		src  IImmutableBox
+		dst  IBox
+		bin  []byte
+		str  string
+		ctx  Context
+	}{
+		{
+			name: "udta 3gpp string",
+			src: &Udta3GppString{
+				AnyTypeBox: AnyTypeBox{Type: StrToBoxType("titl")},
+				Language:   [3]byte{0x5, 0xe, 0x7},
+				Data:       []byte("SING"),
+			},
+			dst: &Udta3GppString{
+				AnyTypeBox: AnyTypeBox{Type: StrToBoxType("titl")},
+			},
+			bin: []byte{
+				0,                // version
+				0x00, 0x00, 0x00, // flags
+				0x15, 0xc7, // language
+				0x53, 0x49, 0x4e, 0x47, // data
+			},
+			str: `Version=0 Flags=0x000000 Language="eng" Data="SING"`,
+			ctx: Context{UnderUdta: true},
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			// Marshal
+			buf := bytes.NewBuffer(nil)
+			n, err := Marshal(buf, tc.src, tc.ctx)
+			require.NoError(t, err)
+			assert.Equal(t, uint64(len(tc.bin)), n)
+			assert.Equal(t, tc.bin, buf.Bytes())
+
+			// Unmarshal
+			r := bytes.NewReader(tc.bin)
+			n, err = Unmarshal(r, uint64(len(tc.bin)), tc.dst, tc.ctx)
+			require.NoError(t, err)
+			assert.Equal(t, uint64(buf.Len()), n)
+			assert.Equal(t, tc.src, tc.dst)
+			s, err := r.Seek(0, io.SeekCurrent)
+			require.NoError(t, err)
+			assert.Equal(t, int64(buf.Len()), s)
+
+			// UnmarshalAny
+			dst, n, err := UnmarshalAny(bytes.NewReader(tc.bin), tc.src.GetType(), uint64(len(tc.bin)), tc.ctx)
+			require.NoError(t, err)
+			assert.Equal(t, uint64(buf.Len()), n)
+			assert.Equal(t, tc.src, dst)
+			s, err = r.Seek(0, io.SeekCurrent)
+			require.NoError(t, err)
+			assert.Equal(t, int64(buf.Len()), s)
+
+			// Stringify
+			str, err := Stringify(tc.src, tc.ctx)
+			require.NoError(t, err)
+			assert.Equal(t, tc.str, str)
+		})
+	}
+}
diff --git a/box_types.go b/box_types_iso14496_12.go
similarity index 85%
rename from box_types.go
rename to box_types_iso14496_12.go
index b077946..b3e46fd 100644
--- a/box_types.go
+++ b/box_types_iso14496_12.go
@@ -1,14 +1,12 @@
 package mp4
 
 import (
-	"bytes"
 	"errors"
 	"fmt"
 	"io"
 
 	"github.com/abema/go-mp4/bitio"
 	"github.com/abema/go-mp4/util"
-	"github.com/google/uuid"
 )
 
 /*************************** btrt ****************************/
@@ -468,129 +466,6 @@ func (*Emsg) GetType() BoxType {
 	return BoxTypeEmsg()
 }
 
-/*************************** esds ****************************/
-
-// https://developer.apple.com/library/content/documentation/QuickTime/QTFF/QTFFChap3/qtff3.html
-
-func BoxTypeEsds() BoxType { return StrToBoxType("esds") }
-
-func init() {
-	AddBoxDef(&Esds{}, 0)
-}
-
-const (
-	ESDescrTag            = 0x03
-	DecoderConfigDescrTag = 0x04
-	DecSpecificInfoTag    = 0x05
-	SLConfigDescrTag      = 0x06
-)
-
-// Esds is ES descripter box
-type Esds struct {
-	FullBox     `mp4:"0,extend"`
-	Descriptors []Descriptor `mp4:"1,array"`
-}
-
-// GetType returns the BoxType
-func (*Esds) GetType() BoxType {
-	return BoxTypeEsds()
-}
-
-type Descriptor struct {
-	BaseCustomFieldObject
-	Tag                     int8                     `mp4:"0,size=8"` // must be 0x03
-	Size                    uint32                   `mp4:"1,varint"`
-	ESDescriptor            *ESDescriptor            `mp4:"2,extend,opt=dynamic"`
-	DecoderConfigDescriptor *DecoderConfigDescriptor `mp4:"3,extend,opt=dynamic"`
-	Data                    []byte                   `mp4:"4,size=8,opt=dynamic,len=dynamic"`
-}
-
-// GetFieldLength returns length of dynamic field
-func (ds *Descriptor) GetFieldLength(name string, ctx Context) uint {
-	switch name {
-	case "Data":
-		return uint(ds.Size)
-	}
-	panic(fmt.Errorf("invalid name of dynamic-length field: boxType=esds fieldName=%s", name))
-}
-
-func (ds *Descriptor) IsOptFieldEnabled(name string, ctx Context) bool {
-	switch ds.Tag {
-	case ESDescrTag:
-		return name == "ESDescriptor"
-	case DecoderConfigDescrTag:
-		return name == "DecoderConfigDescriptor"
-	default:
-		return name == "Data"
-	}
-}
-
-// StringifyField returns field value as string
-func (ds *Descriptor) StringifyField(name string, indent string, depth int, ctx Context) (string, bool) {
-	switch name {
-	case "Tag":
-		switch ds.Tag {
-		case ESDescrTag:
-			return "ESDescr", true
-		case DecoderConfigDescrTag:
-			return "DecoderConfigDescr", true
-		case DecSpecificInfoTag:
-			return "DecSpecificInfo", true
-		case SLConfigDescrTag:
-			return "SLConfigDescr", true
-		default:
-			return "", false
-		}
-	default:
-		return "", false
-	}
-}
-
-type ESDescriptor struct {
-	BaseCustomFieldObject
-	ESID                 uint16 `mp4:"0,size=16"`
-	StreamDependenceFlag bool   `mp4:"1,size=1"`
-	UrlFlag              bool   `mp4:"2,size=1"`
-	OcrStreamFlag        bool   `mp4:"3,size=1"`
-	StreamPriority       int8   `mp4:"4,size=5"`
-	DependsOnESID        uint16 `mp4:"5,size=16,opt=dynamic"`
-	URLLength            uint8  `mp4:"6,size=8,opt=dynamic"`
-	URLString            []byte `mp4:"7,size=8,len=dynamic,opt=dynamic,string"`
-	OCRESID              uint16 `mp4:"8,size=16,opt=dynamic"`
-}
-
-func (esds *ESDescriptor) GetFieldLength(name string, ctx Context) uint {
-	switch name {
-	case "URLString":
-		return uint(esds.URLLength)
-	}
-	panic(fmt.Errorf("invalid name of dynamic-length field: boxType=ESDescriptor fieldName=%s", name))
-}
-
-func (esds *ESDescriptor) IsOptFieldEnabled(name string, ctx Context) bool {
-	switch name {
-	case "DependsOnESID":
-		return esds.StreamDependenceFlag
-	case "URLLength", "URLString":
-		return esds.UrlFlag
-	case "OCRESID":
-		return esds.OcrStreamFlag
-	default:
-		return false
-	}
-}
-
-type DecoderConfigDescriptor struct {
-	BaseCustomFieldObject
-	ObjectTypeIndication byte   `mp4:"0,size=8"`
-	StreamType           int8   `mp4:"1,size=6"`
-	UpStream             bool   `mp4:"2,size=1"`
-	Reserved             bool   `mp4:"3,size=1"`
-	BufferSizeDB         uint32 `mp4:"4,size=24"`
-	MaxBitrate           uint32 `mp4:"5,size=32"`
-	AvgBitrate           uint32 `mp4:"6,size=32"`
-}
-
 /*************************** fiel ****************************/
 
 func BoxTypeFiel() BoxType { return StrToBoxType("fiel") }
@@ -865,171 +740,6 @@ func (hvcc HvcC) GetFieldLength(name string, ctx Context) uint {
 	return 0
 }
 
-/*************************** ilst ****************************/
-
-func BoxTypeIlst() BoxType { return StrToBoxType("ilst") }
-func BoxTypeData() BoxType { return StrToBoxType("data") }
-
-var ilstMetaBoxTypes = []BoxType{
-	StrToBoxType("----"),
-	StrToBoxType("aART"),
-	StrToBoxType("akID"),
-	StrToBoxType("apID"),
-	StrToBoxType("atID"),
-	StrToBoxType("cmID"),
-	StrToBoxType("cnID"),
-	StrToBoxType("covr"),
-	StrToBoxType("cpil"),
-	StrToBoxType("cprt"),
-	StrToBoxType("desc"),
-	StrToBoxType("disk"),
-	StrToBoxType("egid"),
-	StrToBoxType("geID"),
-	StrToBoxType("gnre"),
-	StrToBoxType("pcst"),
-	StrToBoxType("pgap"),
-	StrToBoxType("plID"),
-	StrToBoxType("purd"),
-	StrToBoxType("purl"),
-	StrToBoxType("rtng"),
-	StrToBoxType("sfID"),
-	StrToBoxType("soaa"),
-	StrToBoxType("soal"),
-	StrToBoxType("soar"),
-	StrToBoxType("soco"),
-	StrToBoxType("sonm"),
-	StrToBoxType("sosn"),
-	StrToBoxType("stik"),
-	StrToBoxType("tmpo"),
-	StrToBoxType("trkn"),
-	StrToBoxType("tven"),
-	StrToBoxType("tves"),
-	StrToBoxType("tvnn"),
-	StrToBoxType("tvsh"),
-	StrToBoxType("tvsn"),
-	{0xA9, 'A', 'R', 'T'},
-	{0xA9, 'a', 'l', 'b'},
-	{0xA9, 'c', 'm', 't'},
-	{0xA9, 'c', 'o', 'm'},
-	{0xA9, 'd', 'a', 'y'},
-	{0xA9, 'g', 'e', 'n'},
-	{0xA9, 'g', 'r', 'p'},
-	{0xA9, 'n', 'a', 'm'},
-	{0xA9, 't', 'o', 'o'},
-	{0xA9, 'w', 'r', 't'},
-}
-
-func IsIlstMetaBoxType(boxType BoxType) bool {
-	for _, bt := range ilstMetaBoxTypes {
-		if boxType == bt {
-			return true
-		}
-	}
-	return false
-}
-
-func init() {
-	AddBoxDef(&Ilst{})
-	AddBoxDefEx(&Data{}, isUnderIlstMeta)
-	for _, bt := range ilstMetaBoxTypes {
-		AddAnyTypeBoxDefEx(&IlstMetaContainer{}, bt, isIlstMetaContainer)
-	}
-	AddAnyTypeBoxDefEx(&StringData{}, StrToBoxType("mean"), isUnderIlstFreeFormat)
-	AddAnyTypeBoxDefEx(&StringData{}, StrToBoxType("name"), isUnderIlstFreeFormat)
-}
-
-type Ilst struct {
-	Box
-}
-
-// GetType returns the BoxType
-func (*Ilst) GetType() BoxType {
-	return BoxTypeIlst()
-}
-
-type IlstMetaContainer struct {
-	AnyTypeBox
-}
-
-func isIlstMetaContainer(ctx Context) bool {
-	return ctx.UnderIlst && !ctx.UnderIlstMeta
-}
-
-const (
-	DataTypeBinary             = 0
-	DataTypeStringUTF8         = 1
-	DataTypeStringUTF16        = 2
-	DataTypeStringMac          = 3
-	DataTypeStringJPEG         = 14
-	DataTypeSignedIntBigEndian = 21
-	DataTypeFloat32BigEndian   = 22
-	DataTypeFloat64BigEndian   = 23
-)
-
-type Data struct {
-	Box
-	DataType uint32 `mp4:"0,size=32"`
-	DataLang uint32 `mp4:"1,size=32"`
-	Data     []byte `mp4:"2,size=8"`
-}
-
-// GetType returns the BoxType
-func (*Data) GetType() BoxType {
-	return BoxTypeData()
-}
-
-func isUnderIlstMeta(ctx Context) bool {
-	return ctx.UnderIlstMeta
-}
-
-// StringifyField returns field value as string
-func (data *Data) StringifyField(name string, indent string, depth int, ctx Context) (string, bool) {
-	switch name {
-	case "DataType":
-		switch data.DataType {
-		case DataTypeBinary:
-			return "BINARY", true
-		case DataTypeStringUTF8:
-			return "UTF8", true
-		case DataTypeStringUTF16:
-			return "UTF16", true
-		case DataTypeStringMac:
-			return "MAC_STR", true
-		case DataTypeStringJPEG:
-			return "JPEG", true
-		case DataTypeSignedIntBigEndian:
-			return "INT", true
-		case DataTypeFloat32BigEndian:
-			return "FLOAT32", true
-		case DataTypeFloat64BigEndian:
-			return "FLOAT64", true
-		}
-	case "Data":
-		switch data.DataType {
-		case DataTypeStringUTF8:
-			return fmt.Sprintf("\"%s\"", util.EscapeUnprintables(string(data.Data))), true
-		}
-	}
-	return "", false
-}
-
-type StringData struct {
-	AnyTypeBox
-	Data []byte `mp4:"0,size=8"`
-}
-
-// StringifyField returns field value as string
-func (sd *StringData) StringifyField(name string, indent string, depth int, ctx Context) (string, bool) {
-	if name == "Data" {
-		return fmt.Sprintf("\"%s\"", util.EscapeUnprintables(string(sd.Data))), true
-	}
-	return "", false
-}
-
-func isUnderIlstFreeFormat(ctx Context) bool {
-	return ctx.UnderIlstFreeMeta
-}
-
 /*************************** mdat ****************************/
 
 func BoxTypeMdat() BoxType { return StrToBoxType("mdat") }
@@ -1408,64 +1118,6 @@ func (mvhd *Mvhd) GetRateInt() int16 {
 	return int16(mvhd.Rate >> 16)
 }
 
-/*************************** pssh ****************************/
-
-func BoxTypePssh() BoxType { return StrToBoxType("pssh") }
-
-func init() {
-	AddBoxDef(&Pssh{}, 0, 1)
-}
-
-// Pssh is ISOBMFF pssh box type
-type Pssh struct {
-	FullBox  `mp4:"0,extend"`
-	SystemID [16]byte  `mp4:"1,size=8,uuid"`
-	KIDCount uint32    `mp4:"2,size=32,nver=0"`
-	KIDs     []PsshKID `mp4:"3,nver=0,len=dynamic,size=128"`
-	DataSize int32     `mp4:"4,size=32"`
-	Data     []byte    `mp4:"5,size=8,len=dynamic"`
-}
-
-type PsshKID struct {
-	KID [16]byte `mp4:"0,size=8,uuid"`
-}
-
-// GetFieldLength returns length of dynamic field
-func (pssh *Pssh) GetFieldLength(name string, ctx Context) uint {
-	switch name {
-	case "KIDs":
-		return uint(pssh.KIDCount)
-	case "Data":
-		return uint(pssh.DataSize)
-	}
-	panic(fmt.Errorf("invalid name of dynamic-length field: boxType=pssh fieldName=%s", name))
-}
-
-// StringifyField returns field value as string
-func (pssh *Pssh) StringifyField(name string, indent string, depth int, ctx Context) (string, bool) {
-	switch name {
-	case "KIDs":
-		buf := bytes.NewBuffer(nil)
-		buf.WriteString("[")
-		for i, e := range pssh.KIDs {
-			if i != 0 {
-				buf.WriteString(", ")
-			}
-			buf.WriteString(uuid.UUID(e.KID).String())
-		}
-		buf.WriteString("]")
-		return buf.String(), true
-
-	default:
-		return "", false
-	}
-}
-
-// GetType returns the BoxType
-func (*Pssh) GetType() BoxType {
-	return BoxTypePssh()
-}
-
 /*************************** saio ****************************/
 
 func BoxTypeSaio() BoxType { return StrToBoxType("saio") }
@@ -2325,48 +1977,6 @@ func (*Styp) GetType() BoxType {
 	return BoxTypeStyp()
 }
 
-/*************************** tenc ****************************/
-
-func BoxTypeTenc() BoxType { return StrToBoxType("tenc") }
-
-func init() {
-	AddBoxDef(&Tenc{}, 0, 1)
-}
-
-// Tenc is ISOBMFF tenc box type
-type Tenc struct {
-	FullBox                `mp4:"0,extend"`
-	Reserved               uint8    `mp4:"1,size=8,dec"`
-	DefaultCryptByteBlock  uint8    `mp4:"2,size=4,dec"` // always 0 on version 0
-	DefaultSkipByteBlock   uint8    `mp4:"3,size=4,dec"` // always 0 on version 0
-	DefaultIsProtected     uint8    `mp4:"4,size=8,dec"`
-	DefaultPerSampleIVSize uint8    `mp4:"5,size=8,dec"`
-	DefaultKID             [16]byte `mp4:"6,size=8,uuid"`
-	DefaultConstantIVSize  uint8    `mp4:"7,size=8,opt=dynamic,dec"`
-	DefaultConstantIV      []byte   `mp4:"8,size=8,opt=dynamic,len=dynamic"`
-}
-
-func (tenc *Tenc) IsOptFieldEnabled(name string, ctx Context) bool {
-	switch name {
-	case "DefaultConstantIVSize", "DefaultConstantIV":
-		return tenc.DefaultIsProtected == 1 && tenc.DefaultPerSampleIVSize == 0
-	}
-	return false
-}
-
-func (tenc *Tenc) GetFieldLength(name string, ctx Context) uint {
-	switch name {
-	case "DefaultConstantIV":
-		return uint(tenc.DefaultConstantIVSize)
-	}
-	panic(fmt.Errorf("invalid name of dynamic-length field: boxType=tenc fieldName=%s", name))
-}
-
-// GetType returns the BoxType
-func (*Tenc) GetType() BoxType {
-	return BoxTypeTenc()
-}
-
 /*************************** tfdt ****************************/
 
 func BoxTypeTfdt() BoxType { return StrToBoxType("tfdt") }
@@ -2787,20 +2397,8 @@ func (trun *Trun) GetSampleCompositionTimeOffset(index int) int64 {
 
 func BoxTypeUdta() BoxType { return StrToBoxType("udta") }
 
-var udta3GppMetaBoxTypes = []BoxType{
-	StrToBoxType("titl"),
-	StrToBoxType("dscp"),
-	StrToBoxType("cprt"),
-	StrToBoxType("perf"),
-	StrToBoxType("auth"),
-	StrToBoxType("gnre"),
-}
-
 func init() {
 	AddBoxDef(&Udta{})
-	for _, bt := range udta3GppMetaBoxTypes {
-		AddAnyTypeBoxDefEx(&Udta3GppString{}, bt, isUnderUdta, 0)
-	}
 }
 
 // Udta is ISOBMFF udta box type
@@ -2813,14 +2411,6 @@ func (*Udta) GetType() BoxType {
 	return BoxTypeUdta()
 }
 
-type Udta3GppString struct {
-	AnyTypeBox
-	FullBox  `mp4:"0,extend"`
-	Pad      bool    `mp4:"1,size=1,hidden"`
-	Language [3]byte `mp4:"2,size=5,iso639-2"` // ISO-639-2/T language code
-	Data     []byte  `mp4:"3,size=8,string"`
-}
-
 func isUnderUdta(ctx Context) bool {
 	return ctx.UnderUdta
 }
diff --git a/box_types_test.go b/box_types_iso14496_12_test.go
similarity index 87%
rename from box_types_test.go
rename to box_types_iso14496_12_test.go
index 1ce35f5..1973f3a 100644
--- a/box_types_test.go
+++ b/box_types_iso14496_12_test.go
@@ -10,7 +10,7 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func TestBoxTypes(t *testing.T) {
+func TestBoxTypesISO14496_12(t *testing.T) {
 	testCases := []struct {
 		name string
 		src  IImmutableBox
@@ -372,107 +372,6 @@ func TestBoxTypes(t *testing.T) {
 				`Id=43981 ` +
 				`MessageData="abema"`,
 		},
-		{
-			name: "esds",
-			src: &Esds{
-				FullBox: FullBox{
-					Version: 0,
-					Flags:   [3]byte{0x00, 0x00, 0x00},
-				},
-				Descriptors: []Descriptor{
-					{
-						Tag:  ESDescrTag,
-						Size: 0x1234567,
-						ESDescriptor: &ESDescriptor{
-							ESID:                 0x1234,
-							StreamDependenceFlag: true,
-							UrlFlag:              false,
-							OcrStreamFlag:        true,
-							StreamPriority:       0x03,
-							DependsOnESID:        0x2345,
-							OCRESID:              0x3456,
-						},
-					},
-					{
-						Tag:  ESDescrTag,
-						Size: 0x1234567,
-						ESDescriptor: &ESDescriptor{
-							ESID:                 0x1234,
-							StreamDependenceFlag: false,
-							UrlFlag:              true,
-							OcrStreamFlag:        false,
-							StreamPriority:       0x03,
-							URLLength:            11,
-							URLString:            []byte("http://hoge"),
-						},
-					},
-					{
-						Tag:  DecoderConfigDescrTag,
-						Size: 0x1234567,
-						DecoderConfigDescriptor: &DecoderConfigDescriptor{
-							ObjectTypeIndication: 0x12,
-							StreamType:           0x15,
-							UpStream:             true,
-							Reserved:             false,
-							BufferSizeDB:         0x123456,
-							MaxBitrate:           0x12345678,
-							AvgBitrate:           0x23456789,
-						},
-					},
-					{
-						Tag:  DecSpecificInfoTag,
-						Size: 0x03,
-						Data: []byte{0x11, 0x22, 0x33},
-					},
-					{
-						Tag:  SLConfigDescrTag,
-						Size: 0x05,
-						Data: []byte{0x11, 0x22, 0x33, 0x44, 0x55},
-					},
-				},
-			},
-			dst: &Esds{},
-			bin: []byte{
-				0,                // version
-				0x00, 0x00, 0x00, // flags
-				//
-				0x03,                   // tag
-				0x89, 0x8d, 0x8a, 0x67, // size (varint)
-				0x12, 0x34, // esid
-				0xa3,       // flags & streamPriority
-				0x23, 0x45, // dependsOnESID
-				0x34, 0x56, // ocresid
-				//
-				0x03,                   // tag
-				0x89, 0x8d, 0x8a, 0x67, // size (varint)
-				0x12, 0x34, // esid
-				0x43,                                                  // flags & streamPriority
-				11,                                                    // urlLength
-				'h', 't', 't', 'p', ':', '/', '/', 'h', 'o', 'g', 'e', // urlString
-				//
-				0x04,                   // tag
-				0x89, 0x8d, 0x8a, 0x67, // size (varint)
-				0x12,             // objectTypeIndication
-				0x56,             // streamType & upStream & reserved
-				0x12, 0x34, 0x56, // bufferSizeDB
-				0x12, 0x34, 0x56, 0x78, // maxBitrate
-				0x23, 0x45, 0x67, 0x89, // avgBitrate
-				//
-				0x05,                   // tag
-				0x80, 0x80, 0x80, 0x03, // size (varint)
-				0x11, 0x22, 0x33, // data
-				//
-				0x06,                   // tag
-				0x80, 0x80, 0x80, 0x05, // size (varint)
-				0x11, 0x22, 0x33, 0x44, 0x55, // data
-			},
-			str: `Version=0 Flags=0x000000 Descriptors=[` +
-				`{Tag=ESDescr Size=19088743 ESID=4660 StreamDependenceFlag=true UrlFlag=false OcrStreamFlag=true StreamPriority=3 DependsOnESID=9029 OCRESID=13398}, ` +
-				`{Tag=ESDescr Size=19088743 ESID=4660 StreamDependenceFlag=false UrlFlag=true OcrStreamFlag=false StreamPriority=3 URLLength=0xb URLString="http://hoge"}, ` +
-				`{Tag=DecoderConfigDescr Size=19088743 ObjectTypeIndication=0x12 StreamType=21 UpStream=true Reserved=false BufferSizeDB=1193046 MaxBitrate=305419896 AvgBitrate=591751049}, ` +
-				"{Tag=DecSpecificInfo Size=3 Data=[0x11, 0x22, 0x33]}, " +
-				"{Tag=SLConfigDescr Size=5 Data=[0x11, 0x22, 0x33, 0x44, 0x55]}]",
-		},
 		{
 			name: "fiel",
 			src: &Fiel{
@@ -665,148 +564,6 @@ func TestBoxTypes(t *testing.T) {
 				`{Completeness=false Reserved=false NaluType=0x27 NumNalus=1 Nalus=[{Length=11 NALUnit=[0x4e, 0x1, 0x5, 0xff, 0xff, 0xff, ` +
 				`0xa6, 0x2c, 0xa2, 0xde, 0x9]}]}]`,
 		},
-		{
-			name: "ilst",
-			src:  &Ilst{},
-			dst:  &Ilst{},
-			bin:  nil,
-			str:  ``,
-		},
-		{
-			name: "ilst meta container",
-			src: &IlstMetaContainer{
-				AnyTypeBox: AnyTypeBox{Type: StrToBoxType("----")},
-			},
-			dst: &IlstMetaContainer{
-				AnyTypeBox: AnyTypeBox{Type: StrToBoxType("----")},
-			},
-			bin: nil,
-			str: ``,
-			ctx: Context{UnderIlst: true},
-		},
-		{
-			name: "ilst data (binary)",
-			src:  &Data{DataType: 0, DataLang: 0x12345678, Data: []byte("foo")},
-			dst:  &Data{},
-			bin: []byte{
-				0x00, 0x00, 0x00, 0x00, // data type
-				0x12, 0x34, 0x56, 0x78, // data lang
-				0x66, 0x6f, 0x6f, // data
-			},
-			str: `DataType=BINARY DataLang=305419896 Data=[0x66, 0x6f, 0x6f]`,
-			ctx: Context{UnderIlstMeta: true},
-		},
-		{
-			name: "ilst data (utf8)",
-			src:  &Data{DataType: 1, DataLang: 0x12345678, Data: []byte("foo")},
-			dst:  &Data{},
-			bin: []byte{
-				0x00, 0x00, 0x00, 0x01, // data type
-				0x12, 0x34, 0x56, 0x78, // data lang
-				0x66, 0x6f, 0x6f, // data
-			},
-			str: `DataType=UTF8 DataLang=305419896 Data="foo"`,
-			ctx: Context{UnderIlstMeta: true},
-		},
-		{
-			name: "ilst data (utf8 escaped)",
-			src:  &Data{DataType: 1, DataLang: 0x12345678, Data: []byte{0x00, 'f', 'o', 'o'}},
-			dst:  &Data{},
-			bin: []byte{
-				0x00, 0x00, 0x00, 0x01, // data type
-				0x12, 0x34, 0x56, 0x78, // data lang
-				0x00, 0x66, 0x6f, 0x6f, // data
-			},
-			str: `DataType=UTF8 DataLang=305419896 Data=".foo"`,
-			ctx: Context{UnderIlstMeta: true},
-		},
-		{
-			name: "ilst data (utf16)",
-			src:  &Data{DataType: 2, DataLang: 0x12345678, Data: []byte("foo")},
-			dst:  &Data{},
-			bin: []byte{
-				0x00, 0x00, 0x00, 0x02, // data type
-				0x12, 0x34, 0x56, 0x78, // data lang
-				0x66, 0x6f, 0x6f, // data
-			},
-			str: `DataType=UTF16 DataLang=305419896 Data=[0x66, 0x6f, 0x6f]`,
-			ctx: Context{UnderIlstMeta: true},
-		},
-		{
-			name: "ilst data (mac string)",
-			src:  &Data{DataType: 3, DataLang: 0x12345678, Data: []byte("foo")},
-			dst:  &Data{},
-			bin: []byte{
-				0x00, 0x00, 0x00, 0x03, // data type
-				0x12, 0x34, 0x56, 0x78, // data lang
-				0x66, 0x6f, 0x6f, // data
-			},
-			str: `DataType=MAC_STR DataLang=305419896 Data=[0x66, 0x6f, 0x6f]`,
-			ctx: Context{UnderIlstMeta: true},
-		},
-		{
-			name: "ilst data (jpsg)",
-			src:  &Data{DataType: 14, DataLang: 0x12345678, Data: []byte("foo")},
-			dst:  &Data{},
-			bin: []byte{
-				0x00, 0x00, 0x00, 0x0e, // data type
-				0x12, 0x34, 0x56, 0x78, // data lang
-				0x66, 0x6f, 0x6f, // data
-			},
-			str: `DataType=JPEG DataLang=305419896 Data=[0x66, 0x6f, 0x6f]`,
-			ctx: Context{UnderIlstMeta: true},
-		},
-		{
-			name: "ilst data (int)",
-			src:  &Data{DataType: 21, DataLang: 0x12345678, Data: []byte("foo")},
-			dst:  &Data{},
-			bin: []byte{
-				0x00, 0x00, 0x00, 0x15, // data type
-				0x12, 0x34, 0x56, 0x78, // data lang
-				0x66, 0x6f, 0x6f, // data
-			},
-			str: `DataType=INT DataLang=305419896 Data=[0x66, 0x6f, 0x6f]`,
-			ctx: Context{UnderIlstMeta: true},
-		},
-		{
-			name: "ilst data (float32)",
-			src:  &Data{DataType: 22, DataLang: 0x12345678, Data: []byte("foo")},
-			dst:  &Data{},
-			bin: []byte{
-				0x00, 0x00, 0x00, 0x16, // data type
-				0x12, 0x34, 0x56, 0x78, // data lang
-				0x66, 0x6f, 0x6f, // data
-			},
-			str: `DataType=FLOAT32 DataLang=305419896 Data=[0x66, 0x6f, 0x6f]`,
-			ctx: Context{UnderIlstMeta: true},
-		},
-		{
-			name: "ilst data (float64)",
-			src:  &Data{DataType: 23, DataLang: 0x12345678, Data: []byte("foo")},
-			dst:  &Data{},
-			bin: []byte{
-				0x00, 0x00, 0x00, 0x17, // data type
-				0x12, 0x34, 0x56, 0x78, // data lang
-				0x66, 0x6f, 0x6f, // data
-			},
-			str: `DataType=FLOAT64 DataLang=305419896 Data=[0x66, 0x6f, 0x6f]`,
-			ctx: Context{UnderIlstMeta: true},
-		},
-		{
-			name: "ilst data (string)",
-			src: &StringData{
-				AnyTypeBox: AnyTypeBox{Type: StrToBoxType("mean")},
-				Data:       []byte{0x00, 'f', 'o', 'o'},
-			},
-			dst: &StringData{
-				AnyTypeBox: AnyTypeBox{Type: StrToBoxType("mean")},
-			},
-			bin: []byte{
-				0x00, 0x66, 0x6f, 0x6f, // data
-			},
-			str: `Data=".foo"`,
-			ctx: Context{UnderIlstFreeMeta: true},
-		},
 		{
 			name: "mdat",
 			src: &Mdat{
@@ -1105,67 +862,6 @@ func TestBoxTypes(t *testing.T) {
 				`PreDefined=[0, 0, 0, 0, 0, 0] ` +
 				`NextTrackID=2882400001`,
 		},
-		{
-			name: "pssh: version 0: no KIDs",
-			src: &Pssh{
-				FullBox: FullBox{
-					Version: 0,
-					Flags:   [3]byte{0x00, 0x00, 0x00},
-				},
-				SystemID: [16]byte{0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10},
-				DataSize: 5,
-				Data:     []byte{0x21, 0x22, 0x23, 0x24, 0x25},
-			},
-			dst: &Pssh{},
-			bin: []byte{
-				0,                // version
-				0x00, 0x00, 0x00, // flags
-				// system ID
-				0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10,
-				0x00, 0x00, 0x00, 0x05, // data size
-				0x21, 0x22, 0x23, 0x24, 0x25, // data
-			},
-			str: `Version=0 Flags=0x000000 ` +
-				`SystemID=01020304-0506-0708-090a-0b0c0d0e0f10 ` +
-				`DataSize=5 ` +
-				`Data=[0x21, 0x22, 0x23, 0x24, 0x25]`,
-		},
-		{
-			name: "pssh: version 1: with KIDs",
-			src: &Pssh{
-				FullBox: FullBox{
-					Version: 1,
-					Flags:   [3]byte{0x00, 0x00, 0x00},
-				},
-				SystemID: [16]byte{0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10},
-				KIDCount: 2,
-				KIDs: []PsshKID{
-					{KID: [16]byte{0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x10}},
-					{KID: [16]byte{0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x20}},
-				},
-				DataSize: 5,
-				Data:     []byte{0x21, 0x22, 0x23, 0x24, 0x25},
-			},
-			dst: &Pssh{},
-			bin: []byte{
-				1,                // version
-				0x00, 0x00, 0x00, // flags
-				// system ID
-				0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10,
-				0x00, 0x00, 0x00, 0x02, // KID count
-				// KIDs
-				0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x10,
-				0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x20,
-				0x00, 0x00, 0x00, 0x05, // data size
-				0x21, 0x22, 0x23, 0x24, 0x25, // data
-			},
-			str: `Version=1 Flags=0x000000 ` +
-				`SystemID=01020304-0506-0708-090a-0b0c0d0e0f10 ` +
-				`KIDCount=2 ` +
-				`KIDs=[11121314-1516-1718-191a-1b1c1d1e1f10, 21222324-2526-2728-292a-2b2c2d2e2f20] ` +
-				`DataSize=5 ` +
-				`Data=[0x21, 0x22, 0x23, 0x24, 0x25]`,
-		},
 		{
 			name: "saio: version 0: no aux info type",
 			src: &Saio{
@@ -2518,117 +2214,6 @@ func TestBoxTypes(t *testing.T) {
 			},
 			str: `MajorBrand="abem" MinorVersion=305419896 CompatibleBrands=[{CompatibleBrand="abcd"}, {CompatibleBrand="efgh"}]`,
 		},
-		{
-			name: "tenc: DefaultIsProtected=1 DefaultPerSampleIVSize=0",
-			src: &Tenc{
-				FullBox: FullBox{
-					Version: 1,
-					Flags:   [3]byte{0x00, 0x00, 0x00},
-				},
-				Reserved:               0x00,
-				DefaultCryptByteBlock:  0x0a,
-				DefaultSkipByteBlock:   0x0b,
-				DefaultIsProtected:     1,
-				DefaultPerSampleIVSize: 0,
-				DefaultKID: [16]byte{
-					0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
-					0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
-				},
-				DefaultConstantIVSize: 4,
-				DefaultConstantIV:     []byte{0x01, 0x23, 0x45, 0x67},
-			},
-			dst: &Tenc{},
-			bin: []byte{
-				1,                // version
-				0x00, 0x00, 0x00, // flags
-				0x00,       // reserved
-				0xab,       // default crypt byte block / default skip byte block
-				0x01, 0x00, // default is protected / default per sample iv size
-				0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, // default kid
-				0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
-				0x04,                   // default constant iv size
-				0x01, 0x23, 0x45, 0x67, // default constant iv
-			},
-			str: `Version=1 Flags=0x000000 ` +
-				`Reserved=0 ` +
-				`DefaultCryptByteBlock=10 ` +
-				`DefaultSkipByteBlock=11 ` +
-				`DefaultIsProtected=1 ` +
-				`DefaultPerSampleIVSize=0 ` +
-				`DefaultKID=01234567-89ab-cdef-0123-456789abcdef ` +
-				`DefaultConstantIVSize=4 ` +
-				`DefaultConstantIV=[0x1, 0x23, 0x45, 0x67]`,
-		},
-		{
-			name: "tenc: DefaultIsProtected=0 DefaultPerSampleIVSize=0",
-			src: &Tenc{
-				FullBox: FullBox{
-					Version: 1,
-					Flags:   [3]byte{0x00, 0x00, 0x00},
-				},
-				Reserved:               0x00,
-				DefaultCryptByteBlock:  0x0a,
-				DefaultSkipByteBlock:   0x0b,
-				DefaultIsProtected:     0,
-				DefaultPerSampleIVSize: 0,
-				DefaultKID: [16]byte{
-					0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
-					0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
-				},
-			},
-			dst: &Tenc{},
-			bin: []byte{
-				1,                // version
-				0x00, 0x00, 0x00, // flags
-				0x00,       // reserved
-				0xab,       // default crypt byte block / default skip byte block
-				0x00, 0x00, // default is protected / default per sample iv size
-				0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, // default kid
-				0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
-			},
-			str: `Version=1 Flags=0x000000 ` +
-				`Reserved=0 ` +
-				`DefaultCryptByteBlock=10 ` +
-				`DefaultSkipByteBlock=11 ` +
-				`DefaultIsProtected=0 ` +
-				`DefaultPerSampleIVSize=0 ` +
-				`DefaultKID=01234567-89ab-cdef-0123-456789abcdef`,
-		},
-		{
-			name: "tenc: DefaultIsProtected=1 DefaultPerSampleIVSize=1",
-			src: &Tenc{
-				FullBox: FullBox{
-					Version: 1,
-					Flags:   [3]byte{0x00, 0x00, 0x00},
-				},
-				Reserved:               0x00,
-				DefaultCryptByteBlock:  0x0a,
-				DefaultSkipByteBlock:   0x0b,
-				DefaultIsProtected:     1,
-				DefaultPerSampleIVSize: 1,
-				DefaultKID: [16]byte{
-					0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
-					0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
-				},
-			},
-			dst: &Tenc{},
-			bin: []byte{
-				1,                // version
-				0x00, 0x00, 0x00, // flags
-				0x00,       // reserved
-				0xab,       // default crypt byte block / default skip byte block
-				0x01, 0x01, // default is protected / default per sample iv size
-				0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, // default kid
-				0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
-			},
-			str: `Version=1 Flags=0x000000 ` +
-				`Reserved=0 ` +
-				`DefaultCryptByteBlock=10 ` +
-				`DefaultSkipByteBlock=11 ` +
-				`DefaultIsProtected=1 ` +
-				`DefaultPerSampleIVSize=1 ` +
-				`DefaultKID=01234567-89ab-cdef-0123-456789abcdef`,
-		},
 		{
 			name: "tfdt: version 0",
 			src: &Tfdt{
@@ -3108,25 +2693,6 @@ func TestBoxTypes(t *testing.T) {
 			bin:  nil,
 			str:  ``,
 		},
-		{
-			name: "udta 3gpp string",
-			src: &Udta3GppString{
-				AnyTypeBox: AnyTypeBox{Type: StrToBoxType("titl")},
-				Language:   [3]byte{0x5, 0xe, 0x7},
-				Data:       []byte("SING"),
-			},
-			dst: &Udta3GppString{
-				AnyTypeBox: AnyTypeBox{Type: StrToBoxType("titl")},
-			},
-			bin: []byte{
-				0,                // version
-				0x00, 0x00, 0x00, // flags
-				0x15, 0xc7, // language
-				0x53, 0x49, 0x4e, 0x47, // data
-			},
-			str: `Version=0 Flags=0x000000 Language="eng" Data="SING"`,
-			ctx: Context{UnderUdta: true},
-		},
 		{
 			name: "vmhd",
 			src: &Vmhd{
diff --git a/box_types_iso14496_14.go b/box_types_iso14496_14.go
new file mode 100644
index 0000000..fe9880c
--- /dev/null
+++ b/box_types_iso14496_14.go
@@ -0,0 +1,126 @@
+package mp4
+
+import "fmt"
+
+/*************************** esds ****************************/
+
+// https://developer.apple.com/library/content/documentation/QuickTime/QTFF/QTFFChap3/qtff3.html
+
+func BoxTypeEsds() BoxType { return StrToBoxType("esds") }
+
+func init() {
+	AddBoxDef(&Esds{}, 0)
+}
+
+const (
+	ESDescrTag            = 0x03
+	DecoderConfigDescrTag = 0x04
+	DecSpecificInfoTag    = 0x05
+	SLConfigDescrTag      = 0x06
+)
+
+// Esds is ES descripter box
+type Esds struct {
+	FullBox     `mp4:"0,extend"`
+	Descriptors []Descriptor `mp4:"1,array"`
+}
+
+// GetType returns the BoxType
+func (*Esds) GetType() BoxType {
+	return BoxTypeEsds()
+}
+
+type Descriptor struct {
+	BaseCustomFieldObject
+	Tag                     int8                     `mp4:"0,size=8"` // must be 0x03
+	Size                    uint32                   `mp4:"1,varint"`
+	ESDescriptor            *ESDescriptor            `mp4:"2,extend,opt=dynamic"`
+	DecoderConfigDescriptor *DecoderConfigDescriptor `mp4:"3,extend,opt=dynamic"`
+	Data                    []byte                   `mp4:"4,size=8,opt=dynamic,len=dynamic"`
+}
+
+// GetFieldLength returns length of dynamic field
+func (ds *Descriptor) GetFieldLength(name string, ctx Context) uint {
+	switch name {
+	case "Data":
+		return uint(ds.Size)
+	}
+	panic(fmt.Errorf("invalid name of dynamic-length field: boxType=esds fieldName=%s", name))
+}
+
+func (ds *Descriptor) IsOptFieldEnabled(name string, ctx Context) bool {
+	switch ds.Tag {
+	case ESDescrTag:
+		return name == "ESDescriptor"
+	case DecoderConfigDescrTag:
+		return name == "DecoderConfigDescriptor"
+	default:
+		return name == "Data"
+	}
+}
+
+// StringifyField returns field value as string
+func (ds *Descriptor) StringifyField(name string, indent string, depth int, ctx Context) (string, bool) {
+	switch name {
+	case "Tag":
+		switch ds.Tag {
+		case ESDescrTag:
+			return "ESDescr", true
+		case DecoderConfigDescrTag:
+			return "DecoderConfigDescr", true
+		case DecSpecificInfoTag:
+			return "DecSpecificInfo", true
+		case SLConfigDescrTag:
+			return "SLConfigDescr", true
+		default:
+			return "", false
+		}
+	default:
+		return "", false
+	}
+}
+
+type ESDescriptor struct {
+	BaseCustomFieldObject
+	ESID                 uint16 `mp4:"0,size=16"`
+	StreamDependenceFlag bool   `mp4:"1,size=1"`
+	UrlFlag              bool   `mp4:"2,size=1"`
+	OcrStreamFlag        bool   `mp4:"3,size=1"`
+	StreamPriority       int8   `mp4:"4,size=5"`
+	DependsOnESID        uint16 `mp4:"5,size=16,opt=dynamic"`
+	URLLength            uint8  `mp4:"6,size=8,opt=dynamic"`
+	URLString            []byte `mp4:"7,size=8,len=dynamic,opt=dynamic,string"`
+	OCRESID              uint16 `mp4:"8,size=16,opt=dynamic"`
+}
+
+func (esds *ESDescriptor) GetFieldLength(name string, ctx Context) uint {
+	switch name {
+	case "URLString":
+		return uint(esds.URLLength)
+	}
+	panic(fmt.Errorf("invalid name of dynamic-length field: boxType=ESDescriptor fieldName=%s", name))
+}
+
+func (esds *ESDescriptor) IsOptFieldEnabled(name string, ctx Context) bool {
+	switch name {
+	case "DependsOnESID":
+		return esds.StreamDependenceFlag
+	case "URLLength", "URLString":
+		return esds.UrlFlag
+	case "OCRESID":
+		return esds.OcrStreamFlag
+	default:
+		return false
+	}
+}
+
+type DecoderConfigDescriptor struct {
+	BaseCustomFieldObject
+	ObjectTypeIndication byte   `mp4:"0,size=8"`
+	StreamType           int8   `mp4:"1,size=6"`
+	UpStream             bool   `mp4:"2,size=1"`
+	Reserved             bool   `mp4:"3,size=1"`
+	BufferSizeDB         uint32 `mp4:"4,size=24"`
+	MaxBitrate           uint32 `mp4:"5,size=32"`
+	AvgBitrate           uint32 `mp4:"6,size=32"`
+}
diff --git a/box_types_iso14496_14_test.go b/box_types_iso14496_14_test.go
new file mode 100644
index 0000000..51e2ba1
--- /dev/null
+++ b/box_types_iso14496_14_test.go
@@ -0,0 +1,157 @@
+package mp4
+
+import (
+	"bytes"
+	"io"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestBoxTypesISO14496_14(t *testing.T) {
+	testCases := []struct {
+		name string
+		src  IImmutableBox
+		dst  IBox
+		bin  []byte
+		str  string
+		ctx  Context
+	}{
+		{
+			name: "esds",
+			src: &Esds{
+				FullBox: FullBox{
+					Version: 0,
+					Flags:   [3]byte{0x00, 0x00, 0x00},
+				},
+				Descriptors: []Descriptor{
+					{
+						Tag:  ESDescrTag,
+						Size: 0x1234567,
+						ESDescriptor: &ESDescriptor{
+							ESID:                 0x1234,
+							StreamDependenceFlag: true,
+							UrlFlag:              false,
+							OcrStreamFlag:        true,
+							StreamPriority:       0x03,
+							DependsOnESID:        0x2345,
+							OCRESID:              0x3456,
+						},
+					},
+					{
+						Tag:  ESDescrTag,
+						Size: 0x1234567,
+						ESDescriptor: &ESDescriptor{
+							ESID:                 0x1234,
+							StreamDependenceFlag: false,
+							UrlFlag:              true,
+							OcrStreamFlag:        false,
+							StreamPriority:       0x03,
+							URLLength:            11,
+							URLString:            []byte("http://hoge"),
+						},
+					},
+					{
+						Tag:  DecoderConfigDescrTag,
+						Size: 0x1234567,
+						DecoderConfigDescriptor: &DecoderConfigDescriptor{
+							ObjectTypeIndication: 0x12,
+							StreamType:           0x15,
+							UpStream:             true,
+							Reserved:             false,
+							BufferSizeDB:         0x123456,
+							MaxBitrate:           0x12345678,
+							AvgBitrate:           0x23456789,
+						},
+					},
+					{
+						Tag:  DecSpecificInfoTag,
+						Size: 0x03,
+						Data: []byte{0x11, 0x22, 0x33},
+					},
+					{
+						Tag:  SLConfigDescrTag,
+						Size: 0x05,
+						Data: []byte{0x11, 0x22, 0x33, 0x44, 0x55},
+					},
+				},
+			},
+			dst: &Esds{},
+			bin: []byte{
+				0,                // version
+				0x00, 0x00, 0x00, // flags
+				//
+				0x03,                   // tag
+				0x89, 0x8d, 0x8a, 0x67, // size (varint)
+				0x12, 0x34, // esid
+				0xa3,       // flags & streamPriority
+				0x23, 0x45, // dependsOnESID
+				0x34, 0x56, // ocresid
+				//
+				0x03,                   // tag
+				0x89, 0x8d, 0x8a, 0x67, // size (varint)
+				0x12, 0x34, // esid
+				0x43,                                                  // flags & streamPriority
+				11,                                                    // urlLength
+				'h', 't', 't', 'p', ':', '/', '/', 'h', 'o', 'g', 'e', // urlString
+				//
+				0x04,                   // tag
+				0x89, 0x8d, 0x8a, 0x67, // size (varint)
+				0x12,             // objectTypeIndication
+				0x56,             // streamType & upStream & reserved
+				0x12, 0x34, 0x56, // bufferSizeDB
+				0x12, 0x34, 0x56, 0x78, // maxBitrate
+				0x23, 0x45, 0x67, 0x89, // avgBitrate
+				//
+				0x05,                   // tag
+				0x80, 0x80, 0x80, 0x03, // size (varint)
+				0x11, 0x22, 0x33, // data
+				//
+				0x06,                   // tag
+				0x80, 0x80, 0x80, 0x05, // size (varint)
+				0x11, 0x22, 0x33, 0x44, 0x55, // data
+			},
+			str: `Version=0 Flags=0x000000 Descriptors=[` +
+				`{Tag=ESDescr Size=19088743 ESID=4660 StreamDependenceFlag=true UrlFlag=false OcrStreamFlag=true StreamPriority=3 DependsOnESID=9029 OCRESID=13398}, ` +
+				`{Tag=ESDescr Size=19088743 ESID=4660 StreamDependenceFlag=false UrlFlag=true OcrStreamFlag=false StreamPriority=3 URLLength=0xb URLString="http://hoge"}, ` +
+				`{Tag=DecoderConfigDescr Size=19088743 ObjectTypeIndication=0x12 StreamType=21 UpStream=true Reserved=false BufferSizeDB=1193046 MaxBitrate=305419896 AvgBitrate=591751049}, ` +
+				"{Tag=DecSpecificInfo Size=3 Data=[0x11, 0x22, 0x33]}, " +
+				"{Tag=SLConfigDescr Size=5 Data=[0x11, 0x22, 0x33, 0x44, 0x55]}]",
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			// Marshal
+			buf := bytes.NewBuffer(nil)
+			n, err := Marshal(buf, tc.src, tc.ctx)
+			require.NoError(t, err)
+			assert.Equal(t, uint64(len(tc.bin)), n)
+			assert.Equal(t, tc.bin, buf.Bytes())
+
+			// Unmarshal
+			r := bytes.NewReader(tc.bin)
+			n, err = Unmarshal(r, uint64(len(tc.bin)), tc.dst, tc.ctx)
+			require.NoError(t, err)
+			assert.Equal(t, uint64(buf.Len()), n)
+			assert.Equal(t, tc.src, tc.dst)
+			s, err := r.Seek(0, io.SeekCurrent)
+			require.NoError(t, err)
+			assert.Equal(t, int64(buf.Len()), s)
+
+			// UnmarshalAny
+			dst, n, err := UnmarshalAny(bytes.NewReader(tc.bin), tc.src.GetType(), uint64(len(tc.bin)), tc.ctx)
+			require.NoError(t, err)
+			assert.Equal(t, uint64(buf.Len()), n)
+			assert.Equal(t, tc.src, dst)
+			s, err = r.Seek(0, io.SeekCurrent)
+			require.NoError(t, err)
+			assert.Equal(t, int64(buf.Len()), s)
+
+			// Stringify
+			str, err := Stringify(tc.src, tc.ctx)
+			require.NoError(t, err)
+			assert.Equal(t, tc.str, str)
+		})
+	}
+}
diff --git a/box_types_iso23001_7.go b/box_types_iso23001_7.go
new file mode 100644
index 0000000..766c348
--- /dev/null
+++ b/box_types_iso23001_7.go
@@ -0,0 +1,108 @@
+package mp4
+
+import (
+	"bytes"
+	"fmt"
+
+	"github.com/google/uuid"
+)
+
+/*************************** pssh ****************************/
+
+func BoxTypePssh() BoxType { return StrToBoxType("pssh") }
+
+func init() {
+	AddBoxDef(&Pssh{}, 0, 1)
+}
+
+// Pssh is ISOBMFF pssh box type
+type Pssh struct {
+	FullBox  `mp4:"0,extend"`
+	SystemID [16]byte  `mp4:"1,size=8,uuid"`
+	KIDCount uint32    `mp4:"2,size=32,nver=0"`
+	KIDs     []PsshKID `mp4:"3,nver=0,len=dynamic,size=128"`
+	DataSize int32     `mp4:"4,size=32"`
+	Data     []byte    `mp4:"5,size=8,len=dynamic"`
+}
+
+type PsshKID struct {
+	KID [16]byte `mp4:"0,size=8,uuid"`
+}
+
+// GetFieldLength returns length of dynamic field
+func (pssh *Pssh) GetFieldLength(name string, ctx Context) uint {
+	switch name {
+	case "KIDs":
+		return uint(pssh.KIDCount)
+	case "Data":
+		return uint(pssh.DataSize)
+	}
+	panic(fmt.Errorf("invalid name of dynamic-length field: boxType=pssh fieldName=%s", name))
+}
+
+// StringifyField returns field value as string
+func (pssh *Pssh) StringifyField(name string, indent string, depth int, ctx Context) (string, bool) {
+	switch name {
+	case "KIDs":
+		buf := bytes.NewBuffer(nil)
+		buf.WriteString("[")
+		for i, e := range pssh.KIDs {
+			if i != 0 {
+				buf.WriteString(", ")
+			}
+			buf.WriteString(uuid.UUID(e.KID).String())
+		}
+		buf.WriteString("]")
+		return buf.String(), true
+
+	default:
+		return "", false
+	}
+}
+
+// GetType returns the BoxType
+func (*Pssh) GetType() BoxType {
+	return BoxTypePssh()
+}
+
+/*************************** tenc ****************************/
+
+func BoxTypeTenc() BoxType { return StrToBoxType("tenc") }
+
+func init() {
+	AddBoxDef(&Tenc{}, 0, 1)
+}
+
+// Tenc is ISOBMFF tenc box type
+type Tenc struct {
+	FullBox                `mp4:"0,extend"`
+	Reserved               uint8    `mp4:"1,size=8,dec"`
+	DefaultCryptByteBlock  uint8    `mp4:"2,size=4,dec"` // always 0 on version 0
+	DefaultSkipByteBlock   uint8    `mp4:"3,size=4,dec"` // always 0 on version 0
+	DefaultIsProtected     uint8    `mp4:"4,size=8,dec"`
+	DefaultPerSampleIVSize uint8    `mp4:"5,size=8,dec"`
+	DefaultKID             [16]byte `mp4:"6,size=8,uuid"`
+	DefaultConstantIVSize  uint8    `mp4:"7,size=8,opt=dynamic,dec"`
+	DefaultConstantIV      []byte   `mp4:"8,size=8,opt=dynamic,len=dynamic"`
+}
+
+func (tenc *Tenc) IsOptFieldEnabled(name string, ctx Context) bool {
+	switch name {
+	case "DefaultConstantIVSize", "DefaultConstantIV":
+		return tenc.DefaultIsProtected == 1 && tenc.DefaultPerSampleIVSize == 0
+	}
+	return false
+}
+
+func (tenc *Tenc) GetFieldLength(name string, ctx Context) uint {
+	switch name {
+	case "DefaultConstantIV":
+		return uint(tenc.DefaultConstantIVSize)
+	}
+	panic(fmt.Errorf("invalid name of dynamic-length field: boxType=tenc fieldName=%s", name))
+}
+
+// GetType returns the BoxType
+func (*Tenc) GetType() BoxType {
+	return BoxTypeTenc()
+}
diff --git a/box_types_iso23001_7_test.go b/box_types_iso23001_7_test.go
new file mode 100644
index 0000000..7270e09
--- /dev/null
+++ b/box_types_iso23001_7_test.go
@@ -0,0 +1,228 @@
+package mp4
+
+import (
+	"bytes"
+	"io"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestBoxTypesISO23001_7(t *testing.T) {
+	testCases := []struct {
+		name string
+		src  IImmutableBox
+		dst  IBox
+		bin  []byte
+		str  string
+		ctx  Context
+	}{
+		{
+			name: "pssh: version 0: no KIDs",
+			src: &Pssh{
+				FullBox: FullBox{
+					Version: 0,
+					Flags:   [3]byte{0x00, 0x00, 0x00},
+				},
+				SystemID: [16]byte{0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10},
+				DataSize: 5,
+				Data:     []byte{0x21, 0x22, 0x23, 0x24, 0x25},
+			},
+			dst: &Pssh{},
+			bin: []byte{
+				0,                // version
+				0x00, 0x00, 0x00, // flags
+				// system ID
+				0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10,
+				0x00, 0x00, 0x00, 0x05, // data size
+				0x21, 0x22, 0x23, 0x24, 0x25, // data
+			},
+			str: `Version=0 Flags=0x000000 ` +
+				`SystemID=01020304-0506-0708-090a-0b0c0d0e0f10 ` +
+				`DataSize=5 ` +
+				`Data=[0x21, 0x22, 0x23, 0x24, 0x25]`,
+		},
+		{
+			name: "pssh: version 1: with KIDs",
+			src: &Pssh{
+				FullBox: FullBox{
+					Version: 1,
+					Flags:   [3]byte{0x00, 0x00, 0x00},
+				},
+				SystemID: [16]byte{0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10},
+				KIDCount: 2,
+				KIDs: []PsshKID{
+					{KID: [16]byte{0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x10}},
+					{KID: [16]byte{0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x20}},
+				},
+				DataSize: 5,
+				Data:     []byte{0x21, 0x22, 0x23, 0x24, 0x25},
+			},
+			dst: &Pssh{},
+			bin: []byte{
+				1,                // version
+				0x00, 0x00, 0x00, // flags
+				// system ID
+				0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10,
+				0x00, 0x00, 0x00, 0x02, // KID count
+				// KIDs
+				0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x10,
+				0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x20,
+				0x00, 0x00, 0x00, 0x05, // data size
+				0x21, 0x22, 0x23, 0x24, 0x25, // data
+			},
+			str: `Version=1 Flags=0x000000 ` +
+				`SystemID=01020304-0506-0708-090a-0b0c0d0e0f10 ` +
+				`KIDCount=2 ` +
+				`KIDs=[11121314-1516-1718-191a-1b1c1d1e1f10, 21222324-2526-2728-292a-2b2c2d2e2f20] ` +
+				`DataSize=5 ` +
+				`Data=[0x21, 0x22, 0x23, 0x24, 0x25]`,
+		},
+		{
+			name: "tenc: DefaultIsProtected=1 DefaultPerSampleIVSize=0",
+			src: &Tenc{
+				FullBox: FullBox{
+					Version: 1,
+					Flags:   [3]byte{0x00, 0x00, 0x00},
+				},
+				Reserved:               0x00,
+				DefaultCryptByteBlock:  0x0a,
+				DefaultSkipByteBlock:   0x0b,
+				DefaultIsProtected:     1,
+				DefaultPerSampleIVSize: 0,
+				DefaultKID: [16]byte{
+					0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
+					0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
+				},
+				DefaultConstantIVSize: 4,
+				DefaultConstantIV:     []byte{0x01, 0x23, 0x45, 0x67},
+			},
+			dst: &Tenc{},
+			bin: []byte{
+				1,                // version
+				0x00, 0x00, 0x00, // flags
+				0x00,       // reserved
+				0xab,       // default crypt byte block / default skip byte block
+				0x01, 0x00, // default is protected / default per sample iv size
+				0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, // default kid
+				0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
+				0x04,                   // default constant iv size
+				0x01, 0x23, 0x45, 0x67, // default constant iv
+			},
+			str: `Version=1 Flags=0x000000 ` +
+				`Reserved=0 ` +
+				`DefaultCryptByteBlock=10 ` +
+				`DefaultSkipByteBlock=11 ` +
+				`DefaultIsProtected=1 ` +
+				`DefaultPerSampleIVSize=0 ` +
+				`DefaultKID=01234567-89ab-cdef-0123-456789abcdef ` +
+				`DefaultConstantIVSize=4 ` +
+				`DefaultConstantIV=[0x1, 0x23, 0x45, 0x67]`,
+		},
+		{
+			name: "tenc: DefaultIsProtected=0 DefaultPerSampleIVSize=0",
+			src: &Tenc{
+				FullBox: FullBox{
+					Version: 1,
+					Flags:   [3]byte{0x00, 0x00, 0x00},
+				},
+				Reserved:               0x00,
+				DefaultCryptByteBlock:  0x0a,
+				DefaultSkipByteBlock:   0x0b,
+				DefaultIsProtected:     0,
+				DefaultPerSampleIVSize: 0,
+				DefaultKID: [16]byte{
+					0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
+					0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
+				},
+			},
+			dst: &Tenc{},
+			bin: []byte{
+				1,                // version
+				0x00, 0x00, 0x00, // flags
+				0x00,       // reserved
+				0xab,       // default crypt byte block / default skip byte block
+				0x00, 0x00, // default is protected / default per sample iv size
+				0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, // default kid
+				0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
+			},
+			str: `Version=1 Flags=0x000000 ` +
+				`Reserved=0 ` +
+				`DefaultCryptByteBlock=10 ` +
+				`DefaultSkipByteBlock=11 ` +
+				`DefaultIsProtected=0 ` +
+				`DefaultPerSampleIVSize=0 ` +
+				`DefaultKID=01234567-89ab-cdef-0123-456789abcdef`,
+		},
+		{
+			name: "tenc: DefaultIsProtected=1 DefaultPerSampleIVSize=1",
+			src: &Tenc{
+				FullBox: FullBox{
+					Version: 1,
+					Flags:   [3]byte{0x00, 0x00, 0x00},
+				},
+				Reserved:               0x00,
+				DefaultCryptByteBlock:  0x0a,
+				DefaultSkipByteBlock:   0x0b,
+				DefaultIsProtected:     1,
+				DefaultPerSampleIVSize: 1,
+				DefaultKID: [16]byte{
+					0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
+					0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
+				},
+			},
+			dst: &Tenc{},
+			bin: []byte{
+				1,                // version
+				0x00, 0x00, 0x00, // flags
+				0x00,       // reserved
+				0xab,       // default crypt byte block / default skip byte block
+				0x01, 0x01, // default is protected / default per sample iv size
+				0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, // default kid
+				0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
+			},
+			str: `Version=1 Flags=0x000000 ` +
+				`Reserved=0 ` +
+				`DefaultCryptByteBlock=10 ` +
+				`DefaultSkipByteBlock=11 ` +
+				`DefaultIsProtected=1 ` +
+				`DefaultPerSampleIVSize=1 ` +
+				`DefaultKID=01234567-89ab-cdef-0123-456789abcdef`,
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			// Marshal
+			buf := bytes.NewBuffer(nil)
+			n, err := Marshal(buf, tc.src, tc.ctx)
+			require.NoError(t, err)
+			assert.Equal(t, uint64(len(tc.bin)), n)
+			assert.Equal(t, tc.bin, buf.Bytes())
+
+			// Unmarshal
+			r := bytes.NewReader(tc.bin)
+			n, err = Unmarshal(r, uint64(len(tc.bin)), tc.dst, tc.ctx)
+			require.NoError(t, err)
+			assert.Equal(t, uint64(buf.Len()), n)
+			assert.Equal(t, tc.src, tc.dst)
+			s, err := r.Seek(0, io.SeekCurrent)
+			require.NoError(t, err)
+			assert.Equal(t, int64(buf.Len()), s)
+
+			// UnmarshalAny
+			dst, n, err := UnmarshalAny(bytes.NewReader(tc.bin), tc.src.GetType(), uint64(len(tc.bin)), tc.ctx)
+			require.NoError(t, err)
+			assert.Equal(t, uint64(buf.Len()), n)
+			assert.Equal(t, tc.src, dst)
+			s, err = r.Seek(0, io.SeekCurrent)
+			require.NoError(t, err)
+			assert.Equal(t, int64(buf.Len()), s)
+
+			// Stringify
+			str, err := Stringify(tc.src, tc.ctx)
+			require.NoError(t, err)
+			assert.Equal(t, tc.str, str)
+		})
+	}
+}
diff --git a/box_types_metadata.go b/box_types_metadata.go
new file mode 100644
index 0000000..a56145e
--- /dev/null
+++ b/box_types_metadata.go
@@ -0,0 +1,172 @@
+package mp4
+
+import (
+	"fmt"
+
+	"github.com/abema/go-mp4/util"
+)
+
+/*************************** ilst ****************************/
+
+func BoxTypeIlst() BoxType { return StrToBoxType("ilst") }
+func BoxTypeData() BoxType { return StrToBoxType("data") }
+
+var ilstMetaBoxTypes = []BoxType{
+	StrToBoxType("----"),
+	StrToBoxType("aART"),
+	StrToBoxType("akID"),
+	StrToBoxType("apID"),
+	StrToBoxType("atID"),
+	StrToBoxType("cmID"),
+	StrToBoxType("cnID"),
+	StrToBoxType("covr"),
+	StrToBoxType("cpil"),
+	StrToBoxType("cprt"),
+	StrToBoxType("desc"),
+	StrToBoxType("disk"),
+	StrToBoxType("egid"),
+	StrToBoxType("geID"),
+	StrToBoxType("gnre"),
+	StrToBoxType("pcst"),
+	StrToBoxType("pgap"),
+	StrToBoxType("plID"),
+	StrToBoxType("purd"),
+	StrToBoxType("purl"),
+	StrToBoxType("rtng"),
+	StrToBoxType("sfID"),
+	StrToBoxType("soaa"),
+	StrToBoxType("soal"),
+	StrToBoxType("soar"),
+	StrToBoxType("soco"),
+	StrToBoxType("sonm"),
+	StrToBoxType("sosn"),
+	StrToBoxType("stik"),
+	StrToBoxType("tmpo"),
+	StrToBoxType("trkn"),
+	StrToBoxType("tven"),
+	StrToBoxType("tves"),
+	StrToBoxType("tvnn"),
+	StrToBoxType("tvsh"),
+	StrToBoxType("tvsn"),
+	{0xA9, 'A', 'R', 'T'},
+	{0xA9, 'a', 'l', 'b'},
+	{0xA9, 'c', 'm', 't'},
+	{0xA9, 'c', 'o', 'm'},
+	{0xA9, 'd', 'a', 'y'},
+	{0xA9, 'g', 'e', 'n'},
+	{0xA9, 'g', 'r', 'p'},
+	{0xA9, 'n', 'a', 'm'},
+	{0xA9, 't', 'o', 'o'},
+	{0xA9, 'w', 'r', 't'},
+}
+
+func IsIlstMetaBoxType(boxType BoxType) bool {
+	for _, bt := range ilstMetaBoxTypes {
+		if boxType == bt {
+			return true
+		}
+	}
+	return false
+}
+
+func init() {
+	AddBoxDef(&Ilst{})
+	AddBoxDefEx(&Data{}, isUnderIlstMeta)
+	for _, bt := range ilstMetaBoxTypes {
+		AddAnyTypeBoxDefEx(&IlstMetaContainer{}, bt, isIlstMetaContainer)
+	}
+	AddAnyTypeBoxDefEx(&StringData{}, StrToBoxType("mean"), isUnderIlstFreeFormat)
+	AddAnyTypeBoxDefEx(&StringData{}, StrToBoxType("name"), isUnderIlstFreeFormat)
+}
+
+type Ilst struct {
+	Box
+}
+
+// GetType returns the BoxType
+func (*Ilst) GetType() BoxType {
+	return BoxTypeIlst()
+}
+
+type IlstMetaContainer struct {
+	AnyTypeBox
+}
+
+func isIlstMetaContainer(ctx Context) bool {
+	return ctx.UnderIlst && !ctx.UnderIlstMeta
+}
+
+const (
+	DataTypeBinary             = 0
+	DataTypeStringUTF8         = 1
+	DataTypeStringUTF16        = 2
+	DataTypeStringMac          = 3
+	DataTypeStringJPEG         = 14
+	DataTypeSignedIntBigEndian = 21
+	DataTypeFloat32BigEndian   = 22
+	DataTypeFloat64BigEndian   = 23
+)
+
+type Data struct {
+	Box
+	DataType uint32 `mp4:"0,size=32"`
+	DataLang uint32 `mp4:"1,size=32"`
+	Data     []byte `mp4:"2,size=8"`
+}
+
+// GetType returns the BoxType
+func (*Data) GetType() BoxType {
+	return BoxTypeData()
+}
+
+func isUnderIlstMeta(ctx Context) bool {
+	return ctx.UnderIlstMeta
+}
+
+// StringifyField returns field value as string
+func (data *Data) StringifyField(name string, indent string, depth int, ctx Context) (string, bool) {
+	switch name {
+	case "DataType":
+		switch data.DataType {
+		case DataTypeBinary:
+			return "BINARY", true
+		case DataTypeStringUTF8:
+			return "UTF8", true
+		case DataTypeStringUTF16:
+			return "UTF16", true
+		case DataTypeStringMac:
+			return "MAC_STR", true
+		case DataTypeStringJPEG:
+			return "JPEG", true
+		case DataTypeSignedIntBigEndian:
+			return "INT", true
+		case DataTypeFloat32BigEndian:
+			return "FLOAT32", true
+		case DataTypeFloat64BigEndian:
+			return "FLOAT64", true
+		}
+	case "Data":
+		switch data.DataType {
+		case DataTypeStringUTF8:
+			return fmt.Sprintf("\"%s\"", util.EscapeUnprintables(string(data.Data))), true
+		}
+	}
+	return "", false
+}
+
+type StringData struct {
+	AnyTypeBox
+	Data []byte `mp4:"0,size=8"`
+}
+
+// StringifyField returns field value as string
+func (sd *StringData) StringifyField(name string, indent string, depth int, ctx Context) (string, bool) {
+	if name == "Data" {
+		return fmt.Sprintf("\"%s\"", util.EscapeUnprintables(string(sd.Data))), true
+	}
+	return "", false
+}
+
+func isUnderIlstFreeFormat(ctx Context) bool {
+	return ctx.UnderIlstFreeMeta
+}
diff --git a/box_types_metadata_test.go b/box_types_metadata_test.go
new file mode 100644
index 0000000..ebce386
--- /dev/null
+++ b/box_types_metadata_test.go
@@ -0,0 +1,198 @@
+package mp4
+
+import (
+	"bytes"
+	"io"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestBoxTypesMetadata(t *testing.T) {
+	testCases := []struct {
+		name string
+		src  IImmutableBox
+		dst  IBox
+		bin  []byte
+		str  string
+		ctx  Context
+	}{
+		{
+			name: "ilst",
+			src:  &Ilst{},
+			dst:  &Ilst{},
+			bin:  nil,
+			str:  ``,
+		},
+		{
+			name: "ilst meta container",
+			src: &IlstMetaContainer{
+				AnyTypeBox: AnyTypeBox{Type: StrToBoxType("----")},
+			},
+			dst: &IlstMetaContainer{
+				AnyTypeBox: AnyTypeBox{Type: StrToBoxType("----")},
+			},
+			bin: nil,
+			str: ``,
+			ctx: Context{UnderIlst: true},
+		},
+		{
+			name: "ilst data (binary)",
+			src:  &Data{DataType: 0, DataLang: 0x12345678, Data: []byte("foo")},
+			dst:  &Data{},
+			bin: []byte{
+				0x00, 0x00, 0x00, 0x00, // data type
+				0x12, 0x34, 0x56, 0x78, // data lang
+				0x66, 0x6f, 0x6f, // data
+			},
+			str: `DataType=BINARY DataLang=305419896 Data=[0x66, 0x6f, 0x6f]`,
+			ctx: Context{UnderIlstMeta: true},
+		},
+		{
+			name: "ilst data (utf8)",
+			src:  &Data{DataType: 1, DataLang: 0x12345678, Data: []byte("foo")},
+			dst:  &Data{},
+			bin: []byte{
+				0x00, 0x00, 0x00, 0x01, // data type
+				0x12, 0x34, 0x56, 0x78, // data lang
+				0x66, 0x6f, 0x6f, // data
+			},
+			str: `DataType=UTF8 DataLang=305419896 Data="foo"`,
+			ctx: Context{UnderIlstMeta: true},
+		},
+		{
+			name: "ilst data (utf8 escaped)",
+			src:  &Data{DataType: 1, DataLang: 0x12345678, Data: []byte{0x00, 'f', 'o', 'o'}},
+			dst:  &Data{},
+			bin: []byte{
+				0x00, 0x00, 0x00, 0x01, // data type
+				0x12, 0x34, 0x56, 0x78, // data lang
+				0x00, 0x66, 0x6f, 0x6f, // data
+			},
+			str: `DataType=UTF8 DataLang=305419896 Data=".foo"`,
+			ctx: Context{UnderIlstMeta: true},
+		},
+		{
+			name: "ilst data (utf16)",
+			src:  &Data{DataType: 2, DataLang: 0x12345678, Data: []byte("foo")},
+			dst:  &Data{},
+			bin: []byte{
+				0x00, 0x00, 0x00, 0x02, // data type
+				0x12, 0x34, 0x56, 0x78, // data lang
+				0x66, 0x6f, 0x6f, // data
+			},
+			str: `DataType=UTF16 DataLang=305419896 Data=[0x66, 0x6f, 0x6f]`,
+			ctx: Context{UnderIlstMeta: true},
+		},
+		{
+			name: "ilst data (mac string)",
+			src:  &Data{DataType: 3, DataLang: 0x12345678, Data: []byte("foo")},
+			dst:  &Data{},
+			bin: []byte{
+				0x00, 0x00, 0x00, 0x03, // data type
+				0x12, 0x34, 0x56, 0x78, // data lang
+				0x66, 0x6f, 0x6f, // data
+			},
+			str: `DataType=MAC_STR DataLang=305419896 Data=[0x66, 0x6f, 0x6f]`,
+			ctx: Context{UnderIlstMeta: true},
+		},
+		{
+			name: "ilst data (jpsg)",
+			src:  &Data{DataType: 14, DataLang: 0x12345678, Data: []byte("foo")},
+			dst:  &Data{},
+			bin: []byte{
+				0x00, 0x00, 0x00, 0x0e, // data type
+				0x12, 0x34, 0x56, 0x78, // data lang
+				0x66, 0x6f, 0x6f, // data
+			},
+			str: `DataType=JPEG DataLang=305419896 Data=[0x66, 0x6f, 0x6f]`,
+			ctx: Context{UnderIlstMeta: true},
+		},
+		{
+			name: "ilst data (int)",
+			src:  &Data{DataType: 21, DataLang: 0x12345678, Data: []byte("foo")},
+			dst:  &Data{},
+			bin: []byte{
+				0x00, 0x00, 0x00, 0x15, // data type
+				0x12, 0x34, 0x56, 0x78, // data lang
+				0x66, 0x6f, 0x6f, // data
+			},
+			str: `DataType=INT DataLang=305419896 Data=[0x66, 0x6f, 0x6f]`,
+			ctx: Context{UnderIlstMeta: true},
+		},
+		{
+			name: "ilst data (float32)",
+			src:  &Data{DataType: 22, DataLang: 0x12345678, Data: []byte("foo")},
+			dst:  &Data{},
+			bin: []byte{
+				0x00, 0x00, 0x00, 0x16, // data type
+				0x12, 0x34, 0x56, 0x78, // data lang
+				0x66, 0x6f, 0x6f, // data
+			},
+			str: `DataType=FLOAT32 DataLang=305419896 Data=[0x66, 0x6f, 0x6f]`,
+			ctx: Context{UnderIlstMeta: true},
+		},
+		{
+			name: "ilst data (float64)",
+			src:  &Data{DataType: 23, DataLang: 0x12345678, Data: []byte("foo")},
+			dst:  &Data{},
+			bin: []byte{
+				0x00, 0x00, 0x00, 0x17, // data type
+				0x12, 0x34, 0x56, 0x78, // data lang
+				0x66, 0x6f, 0x6f, // data
+			},
+			str: `DataType=FLOAT64 DataLang=305419896 Data=[0x66, 0x6f, 0x6f]`,
+			ctx: Context{UnderIlstMeta: true},
+		},
+		{
+			name: "ilst data (string)",
+			src: &StringData{
+				AnyTypeBox: AnyTypeBox{Type: StrToBoxType("mean")},
+				Data:       []byte{0x00, 'f', 'o', 'o'},
+			},
+			dst: &StringData{
+				AnyTypeBox: AnyTypeBox{Type: StrToBoxType("mean")},
+			},
+			bin: []byte{
+				0x00, 0x66, 0x6f, 0x6f, // data
+			},
+			str: `Data=".foo"`,
+			ctx: Context{UnderIlstFreeMeta: true},
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			// Marshal
+			buf := bytes.NewBuffer(nil)
+			n, err := Marshal(buf, tc.src, tc.ctx)
+			require.NoError(t, err)
+			assert.Equal(t, uint64(len(tc.bin)), n)
+			assert.Equal(t, tc.bin, buf.Bytes())
+
+			// Unmarshal
+			r := bytes.NewReader(tc.bin)
+			n, err = Unmarshal(r, uint64(len(tc.bin)), tc.dst, tc.ctx)
+			require.NoError(t, err)
+			assert.Equal(t, uint64(buf.Len()), n)
+			assert.Equal(t, tc.src, tc.dst)
+			s, err := r.Seek(0, io.SeekCurrent)
+			require.NoError(t, err)
+			assert.Equal(t, int64(buf.Len()), s)
+
+			// UnmarshalAny
+			dst, n, err := UnmarshalAny(bytes.NewReader(tc.bin), tc.src.GetType(), uint64(len(tc.bin)), tc.ctx)
+			require.NoError(t, err)
+			assert.Equal(t, uint64(buf.Len()), n)
+			assert.Equal(t, tc.src, dst)
+			s, err = r.Seek(0, io.SeekCurrent)
+			require.NoError(t, err)
+			assert.Equal(t, int64(buf.Len()), s)
+
+			// Stringify
+			str, err := Stringify(tc.src, tc.ctx)
+			require.NoError(t, err)
+			assert.Equal(t, tc.str, str)
+		})
+	}
+}