diff --git a/demuxer.go b/demuxer.go
new file mode 100644
index 0000000..b6b18b9
--- /dev/null
+++ b/demuxer.go
@@ -0,0 +1,221 @@
+
+package ts
+
+import (
+	"io"
+	"bytes"
+	"fmt"
+	"github.com/nareix/mp4/isom"
+)
+
+type Demuxer struct {
+	R io.Reader
+
+	pat PAT
+	pmt *PMT
+	Tracks []*Track
+	TrackH264 *Track
+	TrackAAC *Track
+}
+
+// ParsePacket() (pid uint, counter int, isStart bool, pts, dst int64, isKeyFrame bool)
+// WritePayload(pid, pts, dts, isKeyFrame, payloads, isVideoFrame)
+
+func (self *Demuxer) TimeScale() int64 {
+	return PTS_HZ
+}
+
+func (self *Demuxer) ReadHeader() (err error) {
+	self.Tracks = []*Track{}
+	self.TrackH264 = nil
+	self.TrackAAC = nil
+
+	for {
+		if self.pmt != nil {
+			n := 0
+			for _, track := range(self.Tracks) {
+				if track.payloadReady {
+					n++
+				}
+			}
+			if n == len(self.Tracks) {
+				break
+			}
+		}
+
+		if err = self.readPacket(); err != nil {
+			return
+		}
+	}
+
+	return
+}
+
+func (self *Demuxer) ReadSample() (track *Track, err error) {
+	if len(self.Tracks) == 0 {
+		err = fmt.Errorf("no track")
+		return
+	}
+
+	for {
+		for _, _track := range(self.Tracks) {
+			if _track.payloadReady {
+				track = _track
+				return
+			}
+		}
+
+		if err = self.readPacket(); err != nil {
+			return
+		}
+	}
+}
+
+func (self *Demuxer) readPacket() (err error) {
+	var header TSHeader
+	var n int
+	var data [188]byte
+
+	if header, n, err = ReadTSPacket(self.R, data[:]); err != nil {
+		return
+	}
+	payload := data[:n]
+
+	if header.PID == 0 {
+		if self.pat, err = ReadPAT(bytes.NewReader(payload)); err != nil {
+			return
+		}
+	} else {
+		if self.pmt == nil {
+			for _, entry := range(self.pat.Entries) {
+				if entry.ProgramMapPID == header.PID {
+					self.pmt = new(PMT)
+					if *self.pmt, err = ReadPMT(bytes.NewReader(payload)); err != nil {
+						return
+					}
+					for _, info := range(self.pmt.ElementaryStreamInfos) {
+						track := &Track{}
+
+						track.demuxer = self
+						track.pid = info.ElementaryPID
+						switch info.StreamType {
+						case ElementaryStreamTypeH264:
+							track.Type = H264
+							self.TrackH264 = track
+							self.Tracks = append(self.Tracks, track)
+						case ElementaryStreamTypeAdtsAAC:
+							track.Type = AAC
+							self.TrackAAC = track
+							self.Tracks = append(self.Tracks, track)
+						}
+					}
+				}
+			}
+		} else {
+
+			for _, track := range(self.Tracks) {
+				if header.PID == track.pid {
+					if err = track.appendPacket(header, payload); err != nil {
+						return
+					}
+				}
+			}
+		}
+	}
+
+	return
+}
+
+func (self *Track) GetMPEG4AudioConfig() isom.MPEG4AudioConfig {
+	return self.mpeg4AudioConfig
+}
+
+func (self *Track) ReadSample() (pts int64, dts int64, isKeyFrame bool, data []byte, err error) {
+	for !self.payloadReady {
+		if err = self.demuxer.readPacket(); err != nil {
+			return
+		}
+	}
+
+	if self.Type == AAC {
+		var n int
+		if _, data, n, self.payload, err = isom.ReadADTSPayload(self.payload); err != nil {
+			return
+		}
+		pts = self.PTS
+		dts = pts
+		self.PTS += int64(PTS_HZ*n)/int64(self.mpeg4AudioConfig.SampleRate)
+		if len(self.payload) == 0 {
+			self.payloadReady = false
+		}
+	} else {
+		dts = int64(self.peshdr.DTS)
+		pts = int64(self.peshdr.PTS)
+		isKeyFrame = self.tshdr.RandomAccessIndicator
+		data = self.payload
+		self.payloadReady = false
+	}
+
+	if dts == 0 {
+		dts = pts
+	}
+	return
+}
+
+func (self *Track) appendPayload() (err error) {
+	self.payload = self.buf.Bytes()
+	if len(self.payload) == 0 {
+		err = fmt.Errorf("empty payload")
+		return
+	}
+
+	if self.Type == AAC {
+		if !self.mpeg4AudioConfig.IsValid() {
+			if self.mpeg4AudioConfig, _, _, _, err = isom.ReadADTSPayload(self.payload); err != nil {
+				return
+			}
+			self.mpeg4AudioConfig = self.mpeg4AudioConfig.Complete()
+			if !self.mpeg4AudioConfig.IsValid() {
+				err = fmt.Errorf("invalid MPEG4AudioConfig")
+				return
+			}
+		}
+		self.PTS = int64(self.peshdr.PTS)
+	}
+
+	self.payloadReady = true
+	return
+}
+
+func (self *Track) appendPacket(header TSHeader, payload []byte) (err error) {
+	r := bytes.NewReader(payload)
+	lr := &io.LimitedReader{R: r, N: int64(len(payload))}
+
+	if header.PayloadUnitStart && self.peshdr != nil && self.peshdr.DataLength == 0 {
+		if err = self.appendPayload(); err != nil {
+			return
+		}
+	}
+
+	if header.PayloadUnitStart {
+		self.payloadReady = false
+		self.buf = bytes.Buffer{}
+		if self.peshdr, err = ReadPESHeader(lr); err != nil {
+			return
+		}
+		self.tshdr = header
+	}
+
+	if _, err = io.CopyN(&self.buf, lr, lr.N); err != nil {
+		return
+	}
+
+	if self.buf.Len() == int(self.peshdr.DataLength) {
+		if err = self.appendPayload(); err != nil {
+			return
+		}
+	}
+
+	return
+}
+
diff --git a/muxer.go b/muxer.go
index 8da020f..f8a634b 100644
--- a/muxer.go
+++ b/muxer.go
@@ -6,23 +6,6 @@ import (
 	"io"
 )
 
-type Track struct {
-	SPS []byte
-	PPS []byte
-
-	PTS int64
-	TimeScale int64
-
-	writeSPS bool
-	spsHasWritten bool
-
-	mux *Muxer
-	streamId uint
-	tsw *TSWriter
-	dataBuf *iovec
-	cacheSize int
-}
-
 func (self *Track) setPCR() {
 	self.tsw.PCR = uint64(self.PTS)*PCR_HZ/uint64(self.TimeScale)
 }
diff --git a/reader.go b/reader.go
index 72e5e85..dfd01a6 100644
--- a/reader.go
+++ b/reader.go
@@ -96,89 +96,90 @@ func ReadTSHeader(r io.Reader) (self TSHeader, err error) {
 		if length, err = ReadUInt(r, 1); err != nil {
 			return
 		}
-		lr := &io.LimitedReader{R: r, N: int64(length)}
-		if flags, err = ReadUInt(lr, 1); err != nil {
-			return
-		}
-
-		if DebugReader {
-			fmt.Printf("ts: ext_flags %s\n", FieldsDumper{
-				Fields: []struct{
-					Length int
-					Desc string
-				}{
-					{1, "discontinuity_indicator"},
-					{1, "random_access_indicator"},
-					{1, "elementary_stream_priority_indicator"},
-					{1, "pcr_flag"},
-					{1, "opcr_flag"},
-					{1, "splicing_point_flag"},
-					{1, "transport_private_data_flag"},
-					{1, "adaptation_field_extension_flag"},
-				},
-				Val: flags,
-				Length: 8,
-			})
-		}
-
-		// random_access_indicator
-		if flags & 0x40 != 0 {
-			self.RandomAccessIndicator = true
-		}
-
-		// PCR
-		if flags & 0x10 != 0 {
-			var v uint64
-			if v, err = ReadUInt64(lr, 6); err != nil {
+		if length > 0 {
+			lr := &io.LimitedReader{R: r, N: int64(length)}
+			if flags, err = ReadUInt(lr, 1); err != nil {
 				return
 			}
-			// clock is 27MHz
-			self.PCR = UIntToPCR(v)
+
 			if DebugReader {
-				fmt.Printf("ts: PCR %d %f\n", self.PCR, float64(self.PCR)/PCR_HZ)
-			}
-		}
-
-		// OPCR
-		if flags & 0x08 != 0 {
-			var v uint64
-			if v, err = ReadUInt64(lr, 6); err != nil {
-				return
-			}
-			self.OPCR = UIntToPCR(v)
-		}
-
-		// Splice countdown
-		if flags & 0x04 != 0 {
-			if _, err = ReadUInt(lr, 1); err != nil {
-				return
-			}
-		}
-
-		// Transport private data
-		if flags & 0x02 != 0 {
-			var length uint
-			if length, err = ReadUInt(lr, 1); err != nil {
-				return
+				fmt.Printf("ts: ext_flags %s\n", FieldsDumper{
+					Fields: []struct{
+						Length int
+						Desc string
+					}{
+						{1, "discontinuity_indicator"},
+						{1, "random_access_indicator"},
+						{1, "elementary_stream_priority_indicator"},
+						{1, "pcr_flag"},
+						{1, "opcr_flag"},
+						{1, "splicing_point_flag"},
+						{1, "transport_private_data_flag"},
+						{1, "adaptation_field_extension_flag"},
+					},
+					Val: flags,
+					Length: 8,
+				})
 			}
 
-			b := make([]byte, length)
-			if _, err = lr.Read(b); err != nil {
-				return
-			}
-		}
-
-		// Adaptation extension
-		if lr.N > 0 {
-			if DebugReader {
-				// rubish
-				fmt.Println("ts: skip", lr.N)
+			// random_access_indicator
+			if flags & 0x40 != 0 {
+				self.RandomAccessIndicator = true
 			}
 
-			if err = ReadDummy(lr, int(lr.N)); err != nil {
-				return
+			// PCR
+			if flags & 0x10 != 0 {
+				var v uint64
+				if v, err = ReadUInt64(lr, 6); err != nil {
+					return
+				}
+				// clock is 27MHz
+				self.PCR = UIntToPCR(v)
+				if DebugReader {
+					fmt.Printf("ts: PCR %d %f\n", self.PCR, float64(self.PCR)/PCR_HZ)
+				}
 			}
 
+			// OPCR
+			if flags & 0x08 != 0 {
+				var v uint64
+				if v, err = ReadUInt64(lr, 6); err != nil {
+					return
+				}
+				self.OPCR = UIntToPCR(v)
+			}
+
+			// Splice countdown
+			if flags & 0x04 != 0 {
+				if _, err = ReadUInt(lr, 1); err != nil {
+					return
+				}
+			}
+
+			// Transport private data
+			if flags & 0x02 != 0 {
+				var length uint
+				if length, err = ReadUInt(lr, 1); err != nil {
+					return
+				}
+
+				b := make([]byte, length)
+				if _, err = lr.Read(b); err != nil {
+					return
+				}
+			}
+
+			// Adaptation extension
+			if lr.N > 0 {
+				if DebugReader {
+					// rubish
+					fmt.Println("ts: skip", lr.N)
+				}
+
+				if err = ReadDummy(lr, int(lr.N)); err != nil {
+					return
+				}
+			}
 		}
 	}
 
diff --git a/track.go b/track.go
new file mode 100644
index 0000000..a83aa4c
--- /dev/null
+++ b/track.go
@@ -0,0 +1,39 @@
+
+package ts
+
+import (
+	"bytes"
+	"github.com/nareix/mp4/isom"
+)
+
+type Track struct {
+	SPS []byte
+	PPS []byte
+
+	Type int
+
+	pid uint
+	PTS int64
+	TimeScale int64
+
+	mpeg4AudioConfig isom.MPEG4AudioConfig
+	buf bytes.Buffer
+	payload []byte
+	peshdr *PESHeader
+	tshdr TSHeader
+	spsHasWritten bool
+	payloadReady bool
+
+	demuxer *Demuxer
+	mux *Muxer
+	streamId uint
+	tsw *TSWriter
+	dataBuf *iovec
+	cacheSize int
+}
+
+const (
+	H264 = 1
+	AAC = 2
+)
+