diff --git a/writer.go b/writer.go
index dec3690c..6109cd27 100644
--- a/writer.go
+++ b/writer.go
@@ -315,7 +315,7 @@ func (p *MasterPlaylist) String() string {
 // NewMediaPlaylist creates a new media playlist structure. Winsize
 // defines how much items will displayed on playlist generation.
 // Capacity is total size of a playlist.
-func NewMediaPlaylist(winsize uint, capacity uint) (*MediaPlaylist, error) {
+func NewMediaPlaylist(winsize, capacity uint) (*MediaPlaylist, error) {
 	p := new(MediaPlaylist)
 	p.ver = minver
 	p.capacity = capacity
@@ -373,7 +373,7 @@ func (p *MediaPlaylist) AppendSegment(seg *MediaSegment) error {
 	p.tail = (p.tail + 1) % p.capacity
 	p.count++
 	if p.TargetDuration < seg.Duration {
-		p.TargetDuration = math.Ceil(seg.Duration)
+		p.TargetDuration = math.Round(seg.Duration)
 	}
 	p.buf.Reset()
 	return nil
@@ -614,32 +614,32 @@ func (p *MediaPlaylist) Encode() *bytes.Buffer {
 				}
 			}
 		}
-		// check for key change
-		if seg.Key != nil && p.Key != seg.Key {
-			p.buf.WriteString("#EXT-X-KEY:")
-			p.buf.WriteString("METHOD=")
-			p.buf.WriteString(seg.Key.Method)
-			if seg.Key.Method != "NONE" {
-				p.buf.WriteString(",URI=\"")
-				p.buf.WriteString(seg.Key.URI)
-				p.buf.WriteRune('"')
-				if seg.Key.IV != "" {
-					p.buf.WriteString(",IV=")
-					p.buf.WriteString(seg.Key.IV)
-				}
-				if seg.Key.Keyformat != "" {
-					p.buf.WriteString(",KEYFORMAT=\"")
-					p.buf.WriteString(seg.Key.Keyformat)
-					p.buf.WriteRune('"')
-				}
-				if seg.Key.Keyformatversions != "" {
-					p.buf.WriteString(",KEYFORMATVERSIONS=\"")
-					p.buf.WriteString(seg.Key.Keyformatversions)
-					p.buf.WriteRune('"')
-				}
-			}
-			p.buf.WriteRune('\n')
-		}
+		// check for key seg change then change global key as well, but we no need it so comment first
+		// if seg.Key != nil && p.Key != nil && *p.Key != *seg.Key {
+		// 	p.buf.WriteString("#EXT-X-KEY:")
+		// 	p.buf.WriteString("METHOD=")
+		// 	p.buf.WriteString(seg.Key.Method)
+		// 	if seg.Key.Method != "NONE" {
+		// 		p.buf.WriteString(",URI=\"")
+		// 		p.buf.WriteString(seg.Key.URI)
+		// 		p.buf.WriteRune('"')
+		// 		if seg.Key.IV != "" {
+		// 			p.buf.WriteString(",IV=")
+		// 			p.buf.WriteString(seg.Key.IV)
+		// 		}
+		// 		if seg.Key.Keyformat != "" {
+		// 			p.buf.WriteString(",KEYFORMAT=\"")
+		// 			p.buf.WriteString(seg.Key.Keyformat)
+		// 			p.buf.WriteRune('"')
+		// 		}
+		// 		if seg.Key.Keyformatversions != "" {
+		// 			p.buf.WriteString(",KEYFORMATVERSIONS=\"")
+		// 			p.buf.WriteString(seg.Key.Keyformatversions)
+		// 			p.buf.WriteRune('"')
+		// 		}
+		// 	}
+		// 	p.buf.WriteRune('\n')
+		// }
 		if seg.Discontinuity {
 			p.buf.WriteString("#EXT-X-DISCONTINUITY\n")
 		}
@@ -717,12 +717,12 @@ func (p *MediaPlaylist) String() string {
 }
 
 // DurationAsInt represents the duration as the integer in encoded playlist.
-func (p *MediaPlaylist) DurationAsInt(yes bool) {
-	if yes {
+func (p *MediaPlaylist) DurationAsInt(isDurationasInt bool) {
+	if isDurationasInt {
 		// duration must be integers if protocol version is less than 3
 		version(&p.ver, 3)
 	}
-	p.durationAsInt = yes
+	p.durationAsInt = isDurationasInt
 }
 
 // Count tells us the number of items that are currently in the media
@@ -813,7 +813,7 @@ func (p *MediaPlaylist) SetRange(limit, offset int64) error {
 // SetSCTE sets the SCTE cue format for the current media segment.
 //
 // Deprecated: Use SetSCTE35 instead.
-func (p *MediaPlaylist) SetSCTE(cue string, id string, time float64) error {
+func (p *MediaPlaylist) SetSCTE(cue, id string, time float64) error {
 	return p.SetSCTE35(&SCTE{Syntax: SCTE35_67_2014, Cue: cue, ID: id, Time: time})
 }
 
diff --git a/writer_test.go b/writer_test.go
index b4281331..e2d59a30 100644
--- a/writer_test.go
+++ b/writer_test.go
@@ -498,18 +498,17 @@ func TestEncryptionKeysInMediaPlaylist(t *testing.T) {
 	}
 }
 
-func TestEncryptionKeyMethodNoneInMediaPlaylist(t *testing.T) {
+func TestEncryptionKeyMethodNoneInHeaderOfMediaPlaylist(t *testing.T) {
 	p, e := NewMediaPlaylist(5, 5)
+	p.SetDefaultKey("AES-128", "key-uri", "iv", "identity", "1")
 	if e != nil {
 		t.Fatalf("Create media playlist failed: %s", e)
 	}
 	p.Append("segment-1.ts", 4, "")
-	p.SetKey("AES-128", "key-uri", "iv", "identity", "1")
 	p.Append("segment-2.ts", 4, "")
-	p.SetKey("NONE", "", "", "", "")
-	expected := `#EXT-X-KEY:METHOD=NONE
-#EXTINF:4.000,
-segment-2.ts`
+	p.SetDefaultKey("NONE", "key-uri", "iv", "identity", "1")
+	expected := `#EXT-X-VERSION:5
+#EXT-X-KEY:METHOD=NONE`
 	if !strings.Contains(p.String(), expected) {
 		t.Errorf("Manifest %+v did not contain expected %+v", p, expected)
 	}
@@ -817,7 +816,7 @@ func TestNewMasterPlaylistWithClosedCaptionEqNone(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Create media playlist failed: %s", err)
 	}
-	m.Append(fmt.Sprintf("eng_rendition_rendition.m3u8"), p, *vp)
+	m.Append("eng_rendition_rendition.m3u8", p, *vp)
 
 	expected := "CLOSED-CAPTIONS=NONE"
 	if !strings.Contains(m.String(), expected) {
@@ -826,7 +825,7 @@ func TestNewMasterPlaylistWithClosedCaptionEqNone(t *testing.T) {
 	// quotes need to be include if not eq NONE
 	vp.Captions = "CC1"
 	m2 := NewMasterPlaylist()
-	m2.Append(fmt.Sprintf("eng_rendition_rendition.m3u8"), p, *vp)
+	m2.Append("eng_rendition_rendition.m3u8", p, *vp)
 	expected = `CLOSED-CAPTIONS="CC1"`
 	if !strings.Contains(m2.String(), expected) {
 		t.Fatalf("Master playlist did not contain: %s\nMaster Playlist:\n%v", expected, m2.String())
@@ -971,7 +970,7 @@ func ExampleMediaPlaylist_String() {
 // Create new media playlist
 // Add two segments to media playlist
 // Print it
-func ExampleMediaPlaylist_String_Winsize0() {
+func ExampleMediaPlaylist_winsize0() {
 	p, _ := NewMediaPlaylist(0, 2)
 	p.Append("test01.ts", 5.0, "")
 	p.Append("test02.ts", 6.0, "")
@@ -990,7 +989,7 @@ func ExampleMediaPlaylist_String_Winsize0() {
 // Create new media playlist
 // Add two segments to media playlist
 // Print it
-func ExampleMediaPlaylist_String_Winsize0_VOD() {
+func ExampleMediaPlaylist_winsize0_vod() {
 	p, _ := NewMediaPlaylist(0, 2)
 	p.Append("test01.ts", 5.0, "")
 	p.Append("test02.ts", 6.0, "")