diff --git a/atom/genStruct.js b/atom/genStruct.js
index b8abe8e..c62ac57 100644
--- a/atom/genStruct.js
+++ b/atom/genStruct.js
@@ -22,10 +22,10 @@ var atoms = {
 			['flags', 'int24'],
 			['createTime', 'TimeStamp32'],
 			['modifyTime', 'TimeStamp32'],
-			['timeScale', 'TimeStamp32'],
-			['duration', 'TimeStamp32'],
-			['preferredRate', 'int32'],
-			['preferredVolume', 'int16'],
+			['timeScale', 'int32'],
+			['duration', 'int32'],
+			['preferredRate', 'Fixed32'],
+			['preferredVolume', 'Fixed16'],
 			['_', '[10]byte'],
 			['matrix', '[9]int32'],
 			['previewTime', 'TimeStamp32'],
@@ -57,11 +57,11 @@ var atoms = {
 			['modifyTime', 'TimeStamp32'],
 			['trackId', 'int32'],
 			['_', '[4]byte'],
-			['duration', 'TimeStamp32'],
+			['duration', 'int32'],
 			['_', '[8]byte'],
 			['layer', 'int16'],
 			['alternateGroup', 'int16'],
-			['volume', 'int16'],
+			['volume', 'Fixed16'],
 			['_', '[2]byte'],
 			['matrix', '[9]int32'],
 			['trackWidth', 'Fixed32'],
@@ -96,8 +96,8 @@ var atoms = {
 		fields: [
 			['version', 'int8'],
 			['flags', 'int24'],
-			['createTime', 'int32'],
-			['modifyTime', 'int32'],
+			['createTime', 'TimeStamp32'],
+			['modifyTime', 'TimeStamp32'],
 			['timeScale', 'int32'],
 			['duration', 'int32'],
 			['language', 'int16'],
diff --git a/atom/otherStruct.go b/atom/otherStruct.go
index d384b42..c5507f9 100644
--- a/atom/otherStruct.go
+++ b/atom/otherStruct.go
@@ -20,11 +20,13 @@ func CreateAVCDecoderConfRecord(
 	PictureParamSet []byte,
 ) (self AVCDecoderConfRecord, err error) {
 	if len(SeqenceParamSet) < 4 {
-		err = fmt.Errorf("invalid SeqenceParamSet")
+		err = fmt.Errorf("invalid SeqenceParamSet data")
 		return
 	}
 	self.AVCProfileIndication = int(SeqenceParamSet[1])
 	self.AVCLevelIndication = int(SeqenceParamSet[3])
+	self.SeqenceParamSet = [][]byte{SeqenceParamSet}
+	self.PictureParamSet = [][]byte{PictureParamSet}
 	self.LengthSizeMinusOne = 3
 	return
 }
diff --git a/atom/reader.go b/atom/reader.go
index 28bd77d..afaea0a 100644
--- a/atom/reader.go
+++ b/atom/reader.go
@@ -45,7 +45,15 @@ func ReadFixed(r io.Reader, n int) (res Fixed, err error) {
 	if ui, err = ReadUInt(r, n); err != nil {
 		return
 	}
-	res = Fixed(ui)
+
+	if n == 2 {
+		res = Fixed(ui<<8)
+	} else if n == 4 {
+		res = Fixed(ui)
+	} else {
+		panic("only fixed32 and fixed16 is supported")
+	}
+
 	return
 }
 
diff --git a/atom/struct.go b/atom/struct.go
index 6606be2..848298d 100644
--- a/atom/struct.go
+++ b/atom/struct.go
@@ -73,10 +73,10 @@ type MovieHeader struct {
 	Flags             int
 	CreateTime        TimeStamp
 	ModifyTime        TimeStamp
-	TimeScale         TimeStamp
-	Duration          TimeStamp
-	PreferredRate     int
-	PreferredVolume   int
+	TimeScale         int
+	Duration          int
+	PreferredRate     Fixed
+	PreferredVolume   Fixed
 	Matrix            [9]int
 	PreviewTime       TimeStamp
 	PreviewDuration   TimeStamp
@@ -102,16 +102,16 @@ func ReadMovieHeader(r *io.LimitedReader) (res *MovieHeader, err error) {
 	if self.ModifyTime, err = ReadTimeStamp(r, 4); err != nil {
 		return
 	}
-	if self.TimeScale, err = ReadTimeStamp(r, 4); err != nil {
+	if self.TimeScale, err = ReadInt(r, 4); err != nil {
 		return
 	}
-	if self.Duration, err = ReadTimeStamp(r, 4); err != nil {
+	if self.Duration, err = ReadInt(r, 4); err != nil {
 		return
 	}
-	if self.PreferredRate, err = ReadInt(r, 4); err != nil {
+	if self.PreferredRate, err = ReadFixed(r, 4); err != nil {
 		return
 	}
-	if self.PreferredVolume, err = ReadInt(r, 2); err != nil {
+	if self.PreferredVolume, err = ReadFixed(r, 2); err != nil {
 		return
 	}
 	if _, err = ReadDummy(r, 10); err != nil {
@@ -165,16 +165,16 @@ func WriteMovieHeader(w io.WriteSeeker, self *MovieHeader) (err error) {
 	if err = WriteTimeStamp(w, self.ModifyTime, 4); err != nil {
 		return
 	}
-	if err = WriteTimeStamp(w, self.TimeScale, 4); err != nil {
+	if err = WriteInt(w, self.TimeScale, 4); err != nil {
 		return
 	}
-	if err = WriteTimeStamp(w, self.Duration, 4); err != nil {
+	if err = WriteInt(w, self.Duration, 4); err != nil {
 		return
 	}
-	if err = WriteInt(w, self.PreferredRate, 4); err != nil {
+	if err = WriteFixed(w, self.PreferredRate, 4); err != nil {
 		return
 	}
-	if err = WriteInt(w, self.PreferredVolume, 2); err != nil {
+	if err = WriteFixed(w, self.PreferredVolume, 2); err != nil {
 		return
 	}
 	if err = WriteDummy(w, 10); err != nil {
@@ -277,10 +277,10 @@ type TrackHeader struct {
 	CreateTime     TimeStamp
 	ModifyTime     TimeStamp
 	TrackId        int
-	Duration       TimeStamp
+	Duration       int
 	Layer          int
 	AlternateGroup int
-	Volume         int
+	Volume         Fixed
 	Matrix         [9]int
 	TrackWidth     Fixed
 	TrackHeight    Fixed
@@ -307,7 +307,7 @@ func ReadTrackHeader(r *io.LimitedReader) (res *TrackHeader, err error) {
 	if _, err = ReadDummy(r, 4); err != nil {
 		return
 	}
-	if self.Duration, err = ReadTimeStamp(r, 4); err != nil {
+	if self.Duration, err = ReadInt(r, 4); err != nil {
 		return
 	}
 	if _, err = ReadDummy(r, 8); err != nil {
@@ -319,7 +319,7 @@ func ReadTrackHeader(r *io.LimitedReader) (res *TrackHeader, err error) {
 	if self.AlternateGroup, err = ReadInt(r, 2); err != nil {
 		return
 	}
-	if self.Volume, err = ReadInt(r, 2); err != nil {
+	if self.Volume, err = ReadFixed(r, 2); err != nil {
 		return
 	}
 	if _, err = ReadDummy(r, 2); err != nil {
@@ -364,7 +364,7 @@ func WriteTrackHeader(w io.WriteSeeker, self *TrackHeader) (err error) {
 	if err = WriteDummy(w, 4); err != nil {
 		return
 	}
-	if err = WriteTimeStamp(w, self.Duration, 4); err != nil {
+	if err = WriteInt(w, self.Duration, 4); err != nil {
 		return
 	}
 	if err = WriteDummy(w, 8); err != nil {
@@ -376,7 +376,7 @@ func WriteTrackHeader(w io.WriteSeeker, self *TrackHeader) (err error) {
 	if err = WriteInt(w, self.AlternateGroup, 2); err != nil {
 		return
 	}
-	if err = WriteInt(w, self.Volume, 2); err != nil {
+	if err = WriteFixed(w, self.Volume, 2); err != nil {
 		return
 	}
 	if err = WriteDummy(w, 2); err != nil {
@@ -530,8 +530,8 @@ func WriteMedia(w io.WriteSeeker, self *Media) (err error) {
 type MediaHeader struct {
 	Version    int
 	Flags      int
-	CreateTime int
-	ModifyTime int
+	CreateTime TimeStamp
+	ModifyTime TimeStamp
 	TimeScale  int
 	Duration   int
 	Language   int
@@ -547,10 +547,10 @@ func ReadMediaHeader(r *io.LimitedReader) (res *MediaHeader, err error) {
 	if self.Flags, err = ReadInt(r, 3); err != nil {
 		return
 	}
-	if self.CreateTime, err = ReadInt(r, 4); err != nil {
+	if self.CreateTime, err = ReadTimeStamp(r, 4); err != nil {
 		return
 	}
-	if self.ModifyTime, err = ReadInt(r, 4); err != nil {
+	if self.ModifyTime, err = ReadTimeStamp(r, 4); err != nil {
 		return
 	}
 	if self.TimeScale, err = ReadInt(r, 4); err != nil {
@@ -581,10 +581,10 @@ func WriteMediaHeader(w io.WriteSeeker, self *MediaHeader) (err error) {
 	if err = WriteInt(w, self.Flags, 3); err != nil {
 		return
 	}
-	if err = WriteInt(w, self.CreateTime, 4); err != nil {
+	if err = WriteTimeStamp(w, self.CreateTime, 4); err != nil {
 		return
 	}
-	if err = WriteInt(w, self.ModifyTime, 4); err != nil {
+	if err = WriteTimeStamp(w, self.ModifyTime, 4); err != nil {
 		return
 	}
 	if err = WriteInt(w, self.TimeScale, 4); err != nil {
diff --git a/atom/writer.go b/atom/writer.go
index bdcba26..6ddbc96 100644
--- a/atom/writer.go
+++ b/atom/writer.go
@@ -34,7 +34,17 @@ func WriteInt(w io.Writer, val int, n int) (err error) {
 }
 
 func WriteFixed(w io.Writer, val Fixed, n int) (err error) {
-	return WriteUInt(w, uint(val), n)
+	var uval uint
+
+	if n == 2 {
+		uval = uint(val)>>8
+	} else if n == 4 {
+		uval = uint(val)
+	} else {
+		panic("only fixed32 and fixed16 is supported")
+	}
+
+	return WriteUInt(w, uval, n)
 }
 
 func WriteTimeStamp(w io.Writer, ts TimeStamp, n int) (err error) {
diff --git a/avcc.go b/avcc.go
deleted file mode 100644
index b7d1592..0000000
--- a/avcc.go
+++ /dev/null
@@ -1,17 +0,0 @@
-
-package mp4
-
-type Avcc struct {
-	Config []byte
-	W, H int
-	Fps int
-}
-
-// [dur][dur][dur][dur]
-
-// Duration() dur
-// FindKeyFrame(at) at, dur
-// Read(at) at, dur, buf
-// Write(at, buf, dur) at
-// RemoveAll()
-
diff --git a/example/read.go b/example/read.go
index 964a27b..3848402 100644
--- a/example/read.go
+++ b/example/read.go
@@ -13,14 +13,14 @@ func main() {
 	flag.Parse()
 
 	if *testconv {
-		if _, err := mp4.TestConvert(flag.Arg(0)); err != nil {
+		if err := mp4.TestConvert(flag.Arg(0)); err != nil {
 			log.Println(err)
 			return
 		}
 	}
 
 	if *testrewrite {
-		if _, err := mp4.TestRewrite(flag.Arg(0)); err != nil {
+		if err := mp4.TestRewrite(flag.Arg(0)); err != nil {
 			log.Println(err)
 			return
 		}
diff --git a/mp4.go b/mp4.go
deleted file mode 100644
index 723f798..0000000
--- a/mp4.go
+++ /dev/null
@@ -1,494 +0,0 @@
-
-package mp4
-
-import (
-	"./atom"
-	"os"
-	"io"
-	"log"
-	"encoding/hex"
-)
-
-type File struct {
-}
-
-func (self *File) AddAvcc(avcc *Avcc) {
-}
-
-func (self *File) AddMp4a(mp4a *Mp4a) {
-}
-
-func (self *File) GetAvcc() (avcc []*Avcc) {
-	return
-}
-
-func (self *File) GetMp4a() (mp4a []*Mp4a) {
-	return
-}
-
-func (self *File) Sync() {
-}
-
-func (self *File) Close() {
-}
-
-func analyzeSamples(sample *atom.SampleTable) {
-	log.Println("sample:")
-
-	log.Println("HasCompositionOffset", sample.CompositionOffset != nil)
-	log.Println("SampleCount", len(sample.SampleSize.Entries))
-	log.Println("ChunkCount", len(sample.ChunkOffset.Entries))
-
-	log.Println("SampleToChunkCount", len(sample.SampleToChunk.Entries))
-	log.Println("SampleToChunk[0]", sample.SampleToChunk.Entries[0])
-	log.Println("SampleToChunk[1]", sample.SampleToChunk.Entries[1])
-
-	log.Println("TimeToSampleCount", len(sample.TimeToSample.Entries))
-	log.Println("TimeToSample[0]", sample.TimeToSample.Entries[0])
-
-	if sample.SyncSample != nil {
-		log.Println("SyncSampleCount", len(sample.SyncSample.Entries))
-		for i, val := range sample.SyncSample.Entries {
-			if i < 5 {
-				log.Println("SyncSample", i, val)
-			}
-		}
-		log.Println("...")
-	} else {
-		log.Println("NoSyncSample")
-	}
-}
-
-func changeMoov(moov *atom.Movie) {
-	header := moov.Header
-
-	header.CreateTime = atom.TimeStamp(0)
-	header.ModifyTime = atom.TimeStamp(0)
-
-	if true {
-		//log.Println("moov: ", header.CreateTime, header.TimeScale, header.Duration)
-		log.Println("moov: ", header.PreferredRate, header.PreferredVolume)
-		//log.Println("moov: ", header.PreviewTime, header.PreviewDuration)
-		//log.Println("moov: ", header.PosterTime)
-		//log.Println("moov: ", header.SelectionTime, header.SelectionDuration)
-		//log.Println("moov: ", header.CurrentTime)
-		//log.Println("moov: ", header.NextTrackId)
-		//log.Println("moov: ", header.Matrix)
-	}
-
-	for i, track := range moov.Tracks {
-		if true {
-			log.Println("track", i, ":", track.Header.TrackId)
-			log.Println("track", i, ":", track.Header.Duration)
-			//log.Println("track", i, ":", track.Header.Layer, track.Header.AlternateGroup)
-			log.Println("track", i, ":", track.Header.Volume)
-			log.Println("track", i, ":", track.Header.TrackWidth, track.Header.TrackHeight)
-			log.Println("track", i, ":", track.Header.Matrix)
-		}
-
-		media := track.Media
-		if true {
-			log.Println("mediaHeader", media.Header)
-			log.Println("media.hdlr", media.Handler)
-		}
-
-		if minf := media.Info; minf != nil {
-
-			if true {
-				log.Println("minf.video", minf.Video)
-			}
-
-			if sample := minf.Sample; sample != nil {
-				analyzeSamples(sample)
-
-				if desc := sample.SampleDesc; desc != nil {
-
-					if avc1Desc := desc.Avc1Desc; avc1Desc != nil {
-						if conf := avc1Desc.Conf; conf != nil {
-							if true {
-								//log.Println("avc1", hex.Dump(conf.Data))
-								log.Println("avc1desc", conf)
-								//avcconf, _ := atom.ReadAVCDecoderConfRecord(bytes.NewReader(conf.Data))
-								//log.Println("avcconf", avcconf)
-							}
-						}
-					}
-
-					if mp4a := desc.Mp4aDesc; mp4a != nil {
-						if conf := mp4a.Conf; conf != nil {
-							if false {
-							log.Println("mp4a", hex.Dump(conf.Data))
-						}
-						}
-					}
-
-				}
-			}
-		}
-
-	}
-
-}
-
-type Sample struct {
-	Time int
-	Data []byte
-	Sync bool
-}
-
-func readSamples(vsample *atom.SampleTable, mdat io.ReadSeeker, out chan<- Sample) {
-	sampleToChunkIdx := 0
-	chunkIdx := 0
-	nextChunkIdx := 0
-	samplesPerChunk := 0
-
-	updateSamplesPerChunk := func() {
-		chunkIdx = vsample.SampleToChunk.Entries[sampleToChunkIdx].FirstChunk-1
-		samplesPerChunk = vsample.SampleToChunk.Entries[sampleToChunkIdx].SamplesPerChunk
-		sampleToChunkIdx++
-		if sampleToChunkIdx < len(vsample.SampleToChunk.Entries) {
-			nextChunkIdx = vsample.SampleToChunk.Entries[sampleToChunkIdx].FirstChunk-1
-		} else {
-			nextChunkIdx = -1
-		}
-	}
-	updateSamplesPerChunk()
-
-	timeToSampleIdx := 0
-	timeToSampleCount := 0
-	sampleTime := 0
-
-	sampleIdx := 0
-	sampleNr := len(vsample.SampleSize.Entries)
-
-	syncSampleIdx := 0
-	syncSample := vsample.SyncSample.Entries;
-
-	for sampleIdx < sampleNr {
-		if chunkIdx == nextChunkIdx {
-			updateSamplesPerChunk()
-		}
-		sampleOffset := vsample.ChunkOffset.Entries[chunkIdx]
-		for i := 0; i < samplesPerChunk; i++ {
-			sampleSize := vsample.SampleSize.Entries[sampleIdx]
-
-			mdat.Seek(int64(sampleOffset), 0)
-			data := make([]byte, sampleSize)
-			mdat.Read(data)
-
-			var sync bool
-			if syncSampleIdx < len(syncSample) && syncSample[syncSampleIdx]-1 == sampleIdx {
-				sync = true
-				syncSampleIdx++
-			}
-
-			out <- Sample{
-				Time: sampleTime,
-				Data: data,
-				Sync: sync,
-			}
-
-			sampleOffset += sampleSize
-			sampleIdx++
-
-			sampleTime += vsample.TimeToSample.Entries[timeToSampleIdx].Duration
-			timeToSampleCount++
-			if timeToSampleCount == vsample.TimeToSample.Entries[timeToSampleIdx].Count {
-				timeToSampleCount = 0
-				timeToSampleIdx++
-			}
-		}
-		chunkIdx++
-	}
-
-	close(out)
-}
-
-func rewrite(moov *atom.Movie, mdat io.ReadSeeker, outfile io.WriteSeeker) (err error) {
-	var vtrack *atom.Track
-	var vsample *atom.SampleTable
-
-	for _, track := range moov.Tracks {
-		media := track.Media
-		if minf := media.Info; minf != nil {
-			if sample := minf.Sample; sample != nil {
-				if desc := sample.SampleDesc; desc != nil {
-					if avc1Desc := desc.Avc1Desc; avc1Desc != nil {
-						if conf := avc1Desc.Conf; conf != nil {
-							vtrack = track
-							vsample = sample
-						}
-					}
-				}
-			}
-		}
-	}
-
-	sampleCh := make(chan Sample)
-	go readSamples(vsample, mdat, sampleCh)
-
-	log.Println("avc1Desc.conf", vsample.SampleDesc.Avc1Desc.Conf)
-
-	newsample := &atom.SampleTable{
-		SampleDesc: &atom.SampleDesc{
-			Avc1Desc: &atom.Avc1Desc{
-				Conf: vsample.SampleDesc.Avc1Desc.Conf,
-			},
-		},
-		TimeToSample: &atom.TimeToSample{},
-		SampleToChunk: &atom.SampleToChunk{
-			Entries: []atom.SampleToChunkEntry{
-				{
-					FirstChunk: 1,
-					SampleDescId: 1,
-				},
-			},
-		},
-		SampleSize: &atom.SampleSize{},
-		ChunkOffset: &atom.ChunkOffset{
-			Entries: []int{8},
-		},
-		SyncSample: &atom.SyncSample{},
-	}
-	sampleToChunk := &newsample.SampleToChunk.Entries[0]
-
-	var timeToSample *atom.TimeToSampleEntry
-
-	mdatWriter, _ := atom.WriteAtomHeader(outfile, "mdat")
-
-	for sampleIdx := 1; ; sampleIdx++ {
-		if sample, ok := <-sampleCh; ok {
-			if sampleIdx < 10 {
-				log.Println(
-					sampleIdx,
-					"sampleTime", float32(sample.Time)/float32(vtrack.Media.Header.TimeScale)/60.0,
-					"len", len(sample.Data),
-					//"timeToSampleIdx", timeToSampleIdx,
-				)
-			}
-
-			sampleSize := len(sample.Data)
-			sampleDuration := 1000
-			mdatWriter.Write(sample.Data)
-
-			if sample.Sync {
-				newsample.SyncSample.Entries = append(newsample.SyncSample.Entries, sampleIdx)
-			}
-
-			if timeToSample != nil && sampleDuration != timeToSample.Duration {
-				newsample.TimeToSample.Entries = append(newsample.TimeToSample.Entries, *timeToSample)
-				timeToSample = nil
-			}
-			if timeToSample == nil {
-				timeToSample = &atom.TimeToSampleEntry{
-					Duration: sampleDuration,
-				}
-			}
-			timeToSample.Count++
-
-			sampleToChunk.SamplesPerChunk++
-
-			newsample.SampleSize.Entries = append(newsample.SampleSize.Entries, sampleSize)
-		} else {
-			break
-		}
-	}
-
-	if timeToSample != nil {
-		newsample.TimeToSample.Entries = append(newsample.TimeToSample.Entries, *timeToSample)
-	}
-
-	mdatWriter.Close()
-
-	newmoov := &atom.Movie{}
-	newmoov.Header = &atom.MovieHeader{
-		TimeScale: moov.Header.TimeScale,
-		Duration: moov.Header.Duration,
-		PreferredRate: moov.Header.PreferredRate,
-		PreferredVolume: moov.Header.PreferredVolume,
-		Matrix: [9]int{0x10000, 0, 0, 0, 0x10000, 0, 0, 0, 0x40000000},
-	}
-
-	newtrack := &atom.Track{
-		Header: &atom.TrackHeader{
-			Flags: 0x0001, // enabled
-			Duration: vtrack.Header.Duration,
-			Volume: vtrack.Header.Volume,
-			Matrix: [9]int{0x10000, 0, 0, 0, 0x10000, 0, 0, 0, 0x40000000},
-			//TrackWidth: vtrack.Header.TrackWidth,
-			//TrackHeight: vtrack.Header.TrackHeight,
-			TrackId: 1,
-		},
-
-		Media: &atom.Media{
-			Header: &atom.MediaHeader{
-				TimeScale: vtrack.Media.Header.TimeScale,
-				Duration: vtrack.Media.Header.Duration,
-			},
-			Info: &atom.MediaInfo{
-				Video: &atom.VideoMediaInfo{
-					Flags: 0x000001,
-				},
-				Sample: newsample,
-			},
-			Handler: &atom.HandlerRefer{
-				SubType: "vide",
-				Name: "Video Media Handler",
-			},
-		},
-	}
-	newmoov.Tracks = append(newmoov.Tracks, newtrack)
-
-	atom.WriteMovie(outfile, newmoov)
-
-	return
-}
-
-func TestRewrite(filename string) (file *File, err error) {
-	var infile *os.File
-	if infile, err = os.Open(filename); err != nil {
-		return
-	}
-
-	var finfo os.FileInfo
-	if finfo, err = infile.Stat(); err != nil {
-		return
-	}
-	lr := &io.LimitedReader{R: infile, N: finfo.Size()}
-
-	var moov *atom.Movie
-	mdatOffset := int64(-1)
-
-	for lr.N > 0 {
-		var ar *io.LimitedReader
-
-		var cc4 string
-		if ar, cc4, err = atom.ReadAtomHeader(lr, ""); err != nil {
-			return
-		}
-		log.Println("cc4", cc4)
-
-		if cc4 == "moov" {
-			if moov, err = atom.ReadMovie(ar); err != nil {
-				return
-			}
-		} else if cc4 == "mdat" {
-			mdatOffset, _ = infile.Seek(0, 1)
-			break
-		}
-
-		if _, err = atom.ReadDummy(lr, int(ar.N)); err != nil {
-			return
-		}
-	}
-
-	if mdatOffset == -1 {
-		log.Println("mdat not found")
-		return
-	}
-
-	outfileName := filename+".out.mp4"
-	var outfile *os.File
-	if outfile, err = os.Create(outfileName); err != nil {
-		return
-	}
-
-	if err = rewrite(moov, infile, outfile); err != nil {
-		return
-	}
-
-	if err = outfile.Close(); err != nil {
-		return
-	}
-	log.Println("output file", outfileName, "saved")
-
-	return
-}
-
-func TestConvert(filename string) (file *File, err error) {
-	var osfile *os.File
-	if osfile, err = os.Open(filename); err != nil {
-		return
-	}
-
-	var finfo os.FileInfo
-	if finfo, err = osfile.Stat(); err != nil {
-		return
-	}
-	log.Println("filesize", finfo.Size())
-
-	lr := &io.LimitedReader{R: osfile, N: finfo.Size()}
-
-	var outfile *os.File
-	if outfile, err = os.Create(filename+".out.mp4"); err != nil {
-		return
-	}
-
-	for lr.N > 0 {
-		var ar *io.LimitedReader
-
-		var cc4 string
-		if ar, cc4, err = atom.ReadAtomHeader(lr, ""); err != nil {
-			return
-		}
-
-		if cc4 == "moov" {
-
-			curPos, _ := outfile.Seek(0, 1)
-			origSize := ar.N+8
-			var moov *atom.Movie
-			if moov, err = atom.ReadMovie(ar); err != nil {
-				return
-			}
-			changeMoov(moov)
-			if err = atom.WriteMovie(outfile, moov); err != nil {
-				return
-			}
-			curPosAfterRead, _ := outfile.Seek(0, 1)
-			bytesWritten := curPosAfterRead - curPos
-
-			log.Println("regen moov", "tracks nr", len(moov.Tracks),
-				"origSize", origSize, "bytesWritten", bytesWritten,
-			)
-
-			padSize := origSize - bytesWritten - 8
-			aw, _ := atom.WriteAtomHeader(outfile, "free")
-			atom.WriteDummy(outfile, int(padSize))
-			aw.Close()
-
-		} else {
-
-			var outcc4 string
-			if cc4 != "mdat" {
-				outcc4 = "free"
-			} else {
-				outcc4 = "mdat"
-			}
-			var aw *atom.Writer
-			if aw, err = atom.WriteAtomHeader(outfile, outcc4); err != nil {
-				return
-			}
-			log.Println("copy", cc4)
-			if _, err = io.CopyN(aw, ar, ar.N); err != nil {
-				return
-			}
-			if err = aw.Close(); err != nil {
-				return
-			}
-		}
-
-		//log.Println("atom", cc4, "left", lr.N)
-		//atom.ReadDummy(ar, int(ar.N))
-	}
-
-	if err = outfile.Close(); err != nil {
-		return
-	}
-
-	return
-}
-
-func Create(filename string) (file *File, err error) {
-	return
-}
-
diff --git a/mp4a.go b/mp4a.go
deleted file mode 100644
index 614a430..0000000
--- a/mp4a.go
+++ /dev/null
@@ -1,15 +0,0 @@
-
-package mp4
-
-type Mp4a struct {
-	Config []byte
-	SampleRate int
-	Channels int
-}
-
-// [dur][dur][dur][dur]
-
-// Read()
-// Write(i, buf, dur)
-// RemoveAll()
-
diff --git a/writer.go b/writer.go
new file mode 100644
index 0000000..6d60d2c
--- /dev/null
+++ b/writer.go
@@ -0,0 +1,156 @@
+
+package mp4
+
+import (
+	"./atom"
+	"io"
+)
+
+type SimpleH264Writer struct {
+	W io.WriteSeeker
+
+	TimeScale int
+	SPS []byte
+	PPS []byte
+
+	duration int
+
+	sample *atom.SampleTable
+	sampleToChunk *atom.SampleToChunkEntry
+	sampleIdx int
+	timeToSample *atom.TimeToSampleEntry
+
+	mdatWriter *atom.Writer
+}
+
+func (self *SimpleH264Writer) prepare() (err error) {
+	if self.mdatWriter, err = atom.WriteAtomHeader(self.W, "mdat"); err != nil {
+		return
+	}
+
+	self.sampleIdx = 1
+
+	self.sample = &atom.SampleTable{
+		SampleDesc: &atom.SampleDesc{
+			Avc1Desc: &atom.Avc1Desc{
+				Conf: &atom.Avc1Conf{},
+			},
+		},
+		TimeToSample: &atom.TimeToSample{},
+		SampleToChunk: &atom.SampleToChunk{
+			Entries: []atom.SampleToChunkEntry{
+				{
+					FirstChunk: 1,
+					SampleDescId: 1,
+				},
+			},
+		},
+		SampleSize: &atom.SampleSize{},
+		ChunkOffset: &atom.ChunkOffset{
+			Entries: []int{8},
+		},
+		SyncSample: &atom.SyncSample{},
+	}
+	self.sampleToChunk = &self.sample.SampleToChunk.Entries[0]
+
+	return
+}
+
+func (self *SimpleH264Writer) WriteSample(sync bool, duration int, data []byte) (err error) {
+	if self.mdatWriter == nil {
+		if err = self.prepare(); err != nil {
+			return
+		}
+	}
+
+	if _, err = self.mdatWriter.Write(data); err != nil {
+		return
+	}
+
+	if sync {
+		self.sample.SyncSample.Entries = append(self.sample.SyncSample.Entries, self.sampleIdx)
+	}
+
+	if self.timeToSample != nil && duration != self.timeToSample.Duration {
+		self.sample.TimeToSample.Entries = append(self.sample.TimeToSample.Entries, *self.timeToSample)
+		self.timeToSample = nil
+	}
+	if self.timeToSample == nil {
+		self.timeToSample = &atom.TimeToSampleEntry{
+			Duration: duration,
+		}
+	}
+
+	self.duration += duration
+	self.sampleIdx++
+	self.timeToSample.Count++
+	self.sampleToChunk.SamplesPerChunk++
+	self.sample.SampleSize.Entries = append(self.sample.SampleSize.Entries, len(data))
+
+	return
+}
+
+func (self *SimpleH264Writer) Finish() (err error) {
+	self.sample.SampleDesc.Avc1Desc.Conf.Record, err = atom.CreateAVCDecoderConfRecord(
+		self.SPS,
+		self.PPS,
+	)
+	if err != nil {
+		return
+	}
+
+	if self.timeToSample != nil {
+		self.sample.TimeToSample.Entries = append(
+			self.sample.TimeToSample.Entries,
+			*self.timeToSample,
+		)
+	}
+
+	if err = self.mdatWriter.Close(); err != nil {
+		return
+	}
+
+	moov := &atom.Movie{}
+	moov.Header = &atom.MovieHeader{
+		TimeScale: self.TimeScale,
+		Duration: self.duration,
+		PreferredRate: atom.IntToFixed(1),
+		PreferredVolume: atom.IntToFixed(1),
+		Matrix: [9]int{0x10000, 0, 0, 0, 0x10000, 0, 0, 0, 0x40000000},
+	}
+
+	track := &atom.Track{
+		Header: &atom.TrackHeader{
+			Flags: 0x0001, // enabled
+			Duration: self.duration,
+			Volume: atom.IntToFixed(1),
+			Matrix: [9]int{0x10000, 0, 0, 0, 0x10000, 0, 0, 0, 0x40000000},
+			TrackId: 1,
+		},
+
+		Media: &atom.Media{
+			Header: &atom.MediaHeader{
+				TimeScale: self.TimeScale,
+				Duration: self.duration,
+			},
+			Info: &atom.MediaInfo{
+				Video: &atom.VideoMediaInfo{
+					Flags: 0x000001,
+				},
+				Sample: self.sample,
+			},
+			Handler: &atom.HandlerRefer{
+				SubType: "vide",
+				Name: "Video Media Handler",
+			},
+		},
+	}
+	moov.Tracks = append(moov.Tracks, track)
+
+	if err = atom.WriteMovie(self.W, moov); err != nil {
+		return
+	}
+
+	return
+}
+