diff --git a/flac.go b/flac.go
index c370467..5032eae 100644
--- a/flac.go
+++ b/flac.go
@@ -34,12 +34,12 @@ func ReadFLACTags(r io.ReadSeeker) (Metadata, error) {
 		return nil, errors.New("expected 'fLaC'")
 	}
 
-	m := &metadataFLAC{
-		newMetadataVorbis(),
+	m := &MetadataFLAC{
+		NewMetadataVorbis(),
 	}
 
 	for {
-		last, err := m.readFLACMetadataBlock(r)
+		last, err := m.ReadFLACMetadataBlock(r)
 		if err != nil {
 			return nil, err
 		}
@@ -51,11 +51,11 @@ func ReadFLACTags(r io.ReadSeeker) (Metadata, error) {
 	return m, nil
 }
 
-type metadataFLAC struct {
-	*metadataVorbis
+type MetadataFLAC struct {
+	*MetadataVorbis
 }
 
-func (m *metadataFLAC) readFLACMetadataBlock(r io.ReadSeeker) (last bool, err error) {
+func (m *MetadataFLAC) ReadFLACMetadataBlock(r io.ReadSeeker) (last bool, err error) {
 	blockHeader, err := readBytes(r, 1)
 	if err != nil {
 		return
@@ -73,7 +73,7 @@ func (m *metadataFLAC) readFLACMetadataBlock(r io.ReadSeeker) (last bool, err er
 
 	switch blockType(blockHeader[0]) {
 	case vorbisCommentBlock:
-		err = m.readVorbisComment(r)
+		err = m.ReadVorbisComment(r)
 
 	case pictureBlock:
 		err = m.readPictureBlock(r)
@@ -84,6 +84,6 @@ func (m *metadataFLAC) readFLACMetadataBlock(r io.ReadSeeker) (last bool, err er
 	return
 }
 
-func (m *metadataFLAC) FileType() FileType {
+func (m *MetadataFLAC) FileType() FileType {
 	return FLAC
 }
diff --git a/ogg.go b/ogg.go
index f5c4770..ff23e8f 100644
--- a/ogg.go
+++ b/ogg.go
@@ -120,6 +120,9 @@ func (o *oggDemuxer) Read(r io.Reader) ([][]byte, error) {
 	var packets [][]byte
 	var p int
 	for _, s := range segmentTable {
+		if !continued && !bytes.HasPrefix(segmentsData, vorbisCommentPrefix) && !bytes.HasPrefix(segmentsData, opusTagsPrefix) {
+			return nil, fmt.Errorf("not a metadata segment")
+		}
 		packetBuf.Write(segmentsData[p : p+int(s)])
 		if s < 255 {
 			packets = append(packets, packetBuf.Bytes())
@@ -150,15 +153,15 @@ func ReadOGGTags(r io.Reader) (Metadata, error) {
 			switch {
 			case bytes.HasPrefix(b, vorbisCommentPrefix):
 				m := &metadataOGG{
-					newMetadataVorbis(),
+					NewMetadataVorbis(),
 				}
-				err = m.readVorbisComment(bytes.NewReader(b[len(vorbisCommentPrefix):]))
+				err = m.ReadVorbisComment(bytes.NewReader(b[len(vorbisCommentPrefix):]))
 				return m, err
 			case bytes.HasPrefix(b, opusTagsPrefix):
 				m := &metadataOGG{
-					newMetadataVorbis(),
+					NewMetadataVorbis(),
 				}
-				err = m.readVorbisComment(bytes.NewReader(b[len(opusTagsPrefix):]))
+				err = m.ReadVorbisComment(bytes.NewReader(b[len(opusTagsPrefix):]))
 				return m, err
 			}
 		}
@@ -166,7 +169,7 @@ func ReadOGGTags(r io.Reader) (Metadata, error) {
 }
 
 type metadataOGG struct {
-	*metadataVorbis
+	*MetadataVorbis
 }
 
 func (m *metadataOGG) FileType() FileType {
diff --git a/vorbis.go b/vorbis.go
index f1c6a19..1689229 100644
--- a/vorbis.go
+++ b/vorbis.go
@@ -15,18 +15,18 @@ import (
 	"time"
 )
 
-func newMetadataVorbis() *metadataVorbis {
-	return &metadataVorbis{
+func NewMetadataVorbis() *MetadataVorbis {
+	return &MetadataVorbis{
 		c: make(map[string]string),
 	}
 }
 
-type metadataVorbis struct {
+type MetadataVorbis struct {
 	c map[string]string // the vorbis comments
 	p *Picture
 }
 
-func (m *metadataVorbis) readVorbisComment(r io.Reader) error {
+func (m *MetadataVorbis) ReadVorbisComment(r io.Reader) error {
 	vendorLen, err := readUint32LittleEndian(r)
 	if err != nil {
 		return err
@@ -70,7 +70,7 @@ func (m *metadataVorbis) readVorbisComment(r io.Reader) error {
 	return nil
 }
 
-func (m *metadataVorbis) readPictureBlock(r io.Reader) error {
+func (m *MetadataVorbis) readPictureBlock(r io.Reader) error {
 	b, err := readInt(r, 4)
 	if err != nil {
 		return err
@@ -156,11 +156,11 @@ func parseComment(c string) (k, v string, err error) {
 	return
 }
 
-func (m *metadataVorbis) Format() Format {
+func (m *MetadataVorbis) Format() Format {
 	return VORBIS
 }
 
-func (m *metadataVorbis) Raw() map[string]interface{} {
+func (m *MetadataVorbis) Raw() map[string]interface{} {
 	raw := make(map[string]interface{}, len(m.c))
 	for k, v := range m.c {
 		raw[k] = v
@@ -168,11 +168,11 @@ func (m *metadataVorbis) Raw() map[string]interface{} {
 	return raw
 }
 
-func (m *metadataVorbis) Title() string {
+func (m *MetadataVorbis) Title() string {
 	return m.c["title"]
 }
 
-func (m *metadataVorbis) Artist() string {
+func (m *MetadataVorbis) Artist() string {
 	// ARTIST
 	// The artist generally considered responsible for the work. In popular music
 	// this is usually the performing band or singer. For classical music it would
@@ -180,17 +180,17 @@ func (m *metadataVorbis) Artist() string {
 	return m.c["artist"]
 }
 
-func (m *metadataVorbis) Album() string {
+func (m *MetadataVorbis) Album() string {
 	return m.c["album"]
 }
 
-func (m *metadataVorbis) AlbumArtist() string {
+func (m *MetadataVorbis) AlbumArtist() string {
 	// This field isn't actually included in the standard, though
 	// it is commonly assigned to albumartist.
 	return m.c["albumartist"]
 }
 
-func (m *metadataVorbis) Composer() string {
+func (m *MetadataVorbis) Composer() string {
 	if m.c["composer"] != "" {
 		return m.c["composer"]
 	}
@@ -205,11 +205,11 @@ func (m *metadataVorbis) Composer() string {
 	return m.c["artist"]
 }
 
-func (m *metadataVorbis) Genre() string {
+func (m *MetadataVorbis) Genre() string {
 	return m.c["genre"]
 }
 
-func (m *metadataVorbis) Year() int {
+func (m *MetadataVorbis) Year() int {
 	var dateFormat string
 
 	// The date need to follow the international standard https://en.wikipedia.org/wiki/ISO_8601
@@ -236,31 +236,31 @@ func (m *metadataVorbis) Year() int {
 	return t.Year()
 }
 
-func (m *metadataVorbis) Track() (int, int) {
+func (m *MetadataVorbis) Track() (int, int) {
 	x, _ := strconv.Atoi(m.c["tracknumber"])
 	// https://wiki.xiph.org/Field_names
 	n, _ := strconv.Atoi(m.c["tracktotal"])
 	return x, n
 }
 
-func (m *metadataVorbis) Disc() (int, int) {
+func (m *MetadataVorbis) Disc() (int, int) {
 	// https://wiki.xiph.org/Field_names
 	x, _ := strconv.Atoi(m.c["discnumber"])
 	n, _ := strconv.Atoi(m.c["disctotal"])
 	return x, n
 }
 
-func (m *metadataVorbis) Lyrics() string {
+func (m *MetadataVorbis) Lyrics() string {
 	return m.c["lyrics"]
 }
 
-func (m *metadataVorbis) Comment() string {
+func (m *MetadataVorbis) Comment() string {
 	if m.c["comment"] != "" {
 		return m.c["comment"]
 	}
 	return m.c["description"]
 }
 
-func (m *metadataVorbis) Picture() *Picture {
+func (m *MetadataVorbis) Picture() *Picture {
 	return m.p
 }