diff --git a/reader.go b/reader.go
index b19324eb..ce6d3e47 100644
--- a/reader.go
+++ b/reader.go
@@ -193,7 +193,7 @@ func decode(buf *bytes.Buffer, strict bool, customDecoders []CustomDecoder) (Pla
 	wv := new(WV)
 
 	master = NewMasterPlaylist()
-	media, err = NewMediaPlaylist(8, 1024) // Winsize for VoD will become 0, capacity auto extends
+	media, err = NewMediaPlaylist(8, 8*1024) // Winsize for VoD will become 0, capacity auto extends
 	if err != nil {
 		return nil, 0, fmt.Errorf("Create media playlist failed: %s", err)
 	}
diff --git a/structure.go b/structure.go
index eb5d01a2..7a8d9380 100644
--- a/structure.go
+++ b/structure.go
@@ -193,6 +193,7 @@ type Alternative struct {
 	Language        string
 	Name            string
 	Default         bool
+	Channels        string
 	Autoselect      string
 	Forced          string
 	Characteristics string
diff --git a/writer.go b/writer.go
index dec3690c..8f191183 100644
--- a/writer.go
+++ b/writer.go
@@ -93,17 +93,17 @@ func (p *MasterPlaylist) Encode() *bytes.Buffer {
 		}
 	}
 
-	var altsWritten = make(map[string]bool)
+	var altsWritten = make(map[string]struct{})
 
 	for _, pl := range p.Variants {
 		if pl.Alternatives != nil {
 			for _, alt := range pl.Alternatives {
 				// Make sure that we only write out an alternative once
-				altKey := fmt.Sprintf("%s-%s-%s-%s", alt.Type, alt.GroupId, alt.Name, alt.Language)
-				if altsWritten[altKey] {
+				altKey := fmt.Sprintf("%s-%s-%s-%s-%s", alt.Type, alt.GroupId, alt.Name, alt.Language, alt.URI)
+				if _, alreadyWritten := altsWritten[altKey]; alreadyWritten {
 					continue
 				}
-				altsWritten[altKey] = true
+				altsWritten[altKey] = struct{}{}
 
 				p.buf.WriteString("#EXT-X-MEDIA:")
 				if alt.Type != "" {
@@ -126,6 +126,11 @@ func (p *MasterPlaylist) Encode() *bytes.Buffer {
 				} else {
 					p.buf.WriteString("NO")
 				}
+				if alt.Channels != "" {
+					p.buf.WriteString(",CHANNELS=\"")
+					p.buf.WriteString(alt.Channels)
+					p.buf.WriteRune('"')
+				}
 				if alt.Autoselect != "" {
 					p.buf.WriteString(",AUTOSELECT=")
 					p.buf.WriteString(alt.Autoselect)