Support for EXT-X-INDEPENDENT-SEGMENTS tag

reader.go

@@ -226,6 +226,8 @@ func decodeLineOfMasterPlaylist(p *MasterPlaylist, state *decodingState, line st
 		if strict && err != nil {
 			return err
 		}
+	case line == "#EXT-X-INDEPENDENT-SEGMENTS":
+		p.SetIndependentSegments(true)
 	case strings.HasPrefix(line, "#EXT-X-MEDIA:"):
 		var alt Alternative
 		state.listType = MASTER

reader_test.go

@@ -218,6 +218,21 @@ func TestDecodeMasterPlaylistWithStreamInfFrameRate(t *testing.T) {
 	}
 }
 
+func TestDecodeMasterPlaylistWithIndependentSegments(t *testing.T) {
+	f, err := os.Open("sample-playlists/master-with-independent-segments.m3u8")
+	if err != nil {
+		t.Fatal(err)
+	}
+	p := NewMasterPlaylist()
+	err = p.DecodeFrom(bufio.NewReader(f), false)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !p.IndependentSegments() {
+		t.Error("Expected independent segments to be true")
+	}
+}
+
 /****************************
  * Begin Test MediaPlaylist *
  ****************************/

sample-playlists/master-with-independent-segments.m3u8

@@ -0,0 +1,5 @@
+#EXTM3U
+#EXT-X-VERSION:3
+#EXT-X-INDEPENDENT-SEGMENTS
+#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=1828000,NAME="3 high",RESOLUTION=896x504
+chunklist_b1828000_t64NCBoaWdo.m3u8

structure.go

@@ -140,11 +140,12 @@ type MediaPlaylist struct {
    http://example.com/audio-only.m3u8
 */
 type MasterPlaylist struct {
-	Variants      []*Variant
-	Args          string // optional arguments placed after URI (URI?Args)
-	CypherVersion string // non-standard tag for Widevine (see also WV struct)
-	buf           bytes.Buffer
-	ver           uint8
+	Variants            []*Variant
+	Args                string // optional arguments placed after URI (URI?Args)
+	CypherVersion       string // non-standard tag for Widevine (see also WV struct)
+	buf                 bytes.Buffer
+	ver                 uint8
+	independentSegments bool
 }
 
 // This structure represents variants for master playlist.

writer.go

@@ -79,6 +79,10 @@ func (p *MasterPlaylist) Encode() *bytes.Buffer {
 	p.buf.WriteString(strver(p.ver))
 	p.buf.WriteRune('\n')
 
+	if p.IndependentSegments() {
+		p.buf.WriteString("#EXT-X-INDEPENDENT-SEGMENTS\n")
+	}
+
 	var altsWritten map[string]bool = make(map[string]bool)
 
 	for _, pl := range p.Variants {
@@ -249,6 +253,18 @@ func (p *MasterPlaylist) SetVersion(ver uint8) {
 	p.ver = ver
 }
 
+// IndependentSegments returns true if all media samples in a segment can be
+// decoded without information from other segments.
+func (p *MasterPlaylist) IndependentSegments() bool {
+	return p.independentSegments
+}
+
+// SetIndependentSegments sets whether all media samples in a segment can be
+// decoded without information from other segments.
+func (p *MasterPlaylist) SetIndependentSegments(b bool) {
+	p.independentSegments = b
+}
+
 // For compatibility with Stringer interface
 // For example fmt.Printf("%s", sampleMediaList) will encode
 // playist and print its string representation.

writer_test.go

@@ -600,6 +600,20 @@ func TestMediaSetWinSize(t *testing.T) {
 	}
 }
 
+func TestIndependentSegments(t *testing.T) {
+	m := NewMasterPlaylist()
+	if m.IndependentSegments() != false {
+		t.Errorf("Expected independent segments to be false by default")
+	}
+	m.SetIndependentSegments(true)
+	if m.IndependentSegments() != true {
+		t.Errorf("Expected independent segments to be true")
+	}
+	if !strings.Contains(m.Encode().String(), "#EXT-X-INDEPENDENT-SEGMENTS") {
+		t.Error("Expected playlist to contain EXT-X-INDEPENDENT-SEGMENTS tag")
+	}
+}
+
 func TestMediaPlaylist_Slide(t *testing.T) {
 	m, e := NewMediaPlaylist(3, 4)
 	if e != nil {