Merge pull request #40 from amagimedia/master

Parsing SCTE35 tag from playlist

AUTHORS

@@ -12,6 +12,7 @@ to the project. They listed below in an alphabetical order:
 - Kz26
 - Makombo
 - Scott Kidder <[email protected]>
+- Vishal Kumar Tuniki <[email protected]>
 - Zac Shenker <[email protected]>
 
 If you want to be added to this list (or removed for any reason)

reader.go

@@ -443,6 +443,20 @@ func decodeLineOfMediaPlaylist(p *MediaPlaylist, wv *WV, state *decodingState, l
 				return fmt.Errorf("Byterange sub-range offset value parsing error: %s", err)
 			}
 		}
+	case !state.tagSCTE35 && strings.HasPrefix(line, "#EXT-SCTE35:"):
+		state.tagSCTE35 = true
+		state.listType = MEDIA
+		state.scte = new(SCTE)
+		for attribute, value := range decodeParamsLine(line[12:]) {
+			switch attribute {
+			case "CUE":
+				state.scte.Cue = value
+			case "ID":
+				state.scte.ID = value
+			case "TIME":
+				state.scte.Time, _ = strconv.ParseFloat(value, 64)
+			}
+		}
 	case !state.tagInf && strings.HasPrefix(line, "#EXTINF:"):
 		state.tagInf = true
 		state.listType = MEDIA
@@ -471,6 +485,13 @@ func decodeLineOfMediaPlaylist(p *MediaPlaylist, wv *WV, state *decodingState, l
 			}
 			state.tagRange = false
 		}
+		if state.tagSCTE35 {
+			state.tagSCTE35 = false
+			scte := *state.scte
+			if err = p.SetSCTE(scte.Cue, scte.ID, scte.Time); strict && err != nil {
+				return err
+			}
+		}
 		if state.tagDiscontinuity {
 			state.tagDiscontinuity = false
 			if err = p.SetDiscontinuity(); strict && err != nil {

reader_test.go

@@ -243,3 +243,51 @@ func ExampleMediaPlaylist_DurationAsInt() {
 	// #EXTINF:10,
 	// movieB.ts
 }
+
+func TestMediaPlaylistWithSCTE35Tag(t *testing.T) {
+	test_cases := []struct {
+		playlistLocation  string
+		expectedSCTEIndex int
+		expectedSCTECue   string
+		expectedSCTEID    string
+		expectedSCTETime  float64
+	}{
+		{
+			"sample-playlists/media-playlist-with-scte35.m3u8",
+			2,
+			"/DAIAAAAAAAAAAAQAAZ/I0VniQAQAgBDVUVJQAAAAH+cAAAAAA==",
+			"123",
+			123.12,
+		},
+		{
+			"sample-playlists/media-playlist-with-scte35-1.m3u8",
+			1,
+			"/DAIAAAAAAAAAAAQAAZ/I0VniQAQAgBDVUVJQAA",
+			"",
+			0,
+		},
+	}
+	for _, c := range test_cases {
+		f, _ := os.Open(c.playlistLocation)
+		playlist, _, _ := DecodeFrom(bufio.NewReader(f), true)
+		mediaPlaylist := playlist.(*MediaPlaylist)
+		for index, item := range mediaPlaylist.Segments {
+			if item == nil {
+				break
+			}
+			if index != c.expectedSCTEIndex && item.SCTE != nil {
+				t.Error("Not expecting SCTE information on this segment")
+			} else if index == c.expectedSCTEIndex && item.SCTE == nil {
+				t.Error("Expecting SCTE information on this segment")
+			} else if index == c.expectedSCTEIndex && item.SCTE != nil {
+				if (*item.SCTE).Cue != c.expectedSCTECue {
+					t.Error("Expected ", c.expectedSCTECue, " got ", (*item.SCTE).Cue)
+				} else if (*item.SCTE).ID != c.expectedSCTEID {
+					t.Error("Expected ", c.expectedSCTEID, " got ", (*item.SCTE).ID)
+				} else if (*item.SCTE).Time != c.expectedSCTETime {
+					t.Error("Expected ", c.expectedSCTETime, " got ", (*item.SCTE).Time)
+				}
+			}
+		}
+	}
+}

sample-playlists/media-playlist-with-scte35-1.m3u8

@@ -0,0 +1,11 @@
+#EXTM3U
+#EXT-X-TARGETDURATION:10
+#EXT-X-VERSION:3
+#EXT-X-MEDIA-SEQUENCE:0
+#EXTINF:10.000,
+media0.ts
+#EXT-SCTE35: CUE="/DAIAAAAAAAAAAAQAAZ/I0VniQAQAgBDVUVJQAA"
+#EXTINF:10.000,
+media1.ts
+#EXTINF:10.000,
+media2.ts

sample-playlists/media-playlist-with-scte35.m3u8

@@ -0,0 +1,11 @@
+#EXTM3U
+#EXT-X-TARGETDURATION:10
+#EXT-X-VERSION:3
+#EXT-X-MEDIA-SEQUENCE:0
+#EXTINF:10.000,
+media0.ts
+#EXTINF:10.000,
+media1.ts
+#EXT-SCTE35: CUE="/DAIAAAAAAAAAAAQAAZ/I0VniQAQAgBDVUVJQAAAAH+cAAAAAA==", ID="123", TIME=123.12
+#EXTINF:10.000,
+media2.ts

structure.go

@@ -188,9 +188,16 @@ type MediaSegment struct {
 	Key             *Key      // EXT-X-KEY displayed before the segment and means changing of encryption key (in theory each segment may have own key)
 	Map             *Map      // EXT-X-MAP displayed before the segment
 	Discontinuity   bool      // EXT-X-DISCONTINUITY indicates an encoding discontinuity between the media segment that follows it and the one that preceded it (i.e. file format, number and type of tracks, encoding parameters, encoding sequence, timestamp sequence)
+	SCTE            *SCTE     // EXT-SCTE35 used for Ad signaling in HLS
 	ProgramDateTime time.Time // EXT-X-PROGRAM-DATE-TIME tag associates the first sample of a media segment with an absolute date and/or time
 }
 
+type SCTE struct {
+	Cue  string
+	ID   string
+	Time float64
+}
+
 // This structure represents information about stream encryption.
 //
 // Realizes EXT-X-KEY tag.
@@ -252,6 +259,7 @@ type decodingState struct {
 	tagStreamInf       bool
 	tagIframeStreamInf bool
 	tagInf             bool
+	tagSCTE35          bool
 	tagRange           bool
 	tagDiscontinuity   bool
 	tagProgramDateTime bool
@@ -264,4 +272,5 @@ type decodingState struct {
 	variant            *Variant
 	xkey               *Key
 	xmap               *Map
+	scte               *SCTE
 }

writer.go

@@ -609,6 +609,14 @@ func (p *MediaPlaylist) SetRange(limit, offset int64) error {
 	return nil
 }
 
+func (p *MediaPlaylist) SetSCTE(cue string, id string, time float64) error {
+	if p.count == 0 {
+		return errors.New("playlist is empty")
+	}
+	p.Segments[(p.tail-1)%p.capacity].SCTE = &SCTE{cue, id, time}
+	return nil
+}
+
 // Set discontinuity flag for the current media segment.
 // EXT-X-DISCONTINUITY indicates an encoding discontinuity between the media segment
 // that follows it and the one that preceded it (i.e. file format, number and type of tracks,