streaming

commit 6c65438854fef924686286ebc2b20dbfd647c52b
parent 314f50a588e4e749071e0aa8d51a1b4aa16fad7b
Author: Oliver Lowe <o@olowe.co>
Date:   Thu, 23 May 2024 19:39:41 +1000

m3u8: handle writing master playlist renditions

Enough for Tears of Steel from test-streams.mux.dev.

Diffstat:
M
m3u8/parse.go
 | 
19
+++++++++++--------
M
m3u8/write.go
 | 
61
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--

2 files changed, 70 insertions(+), 10 deletions(-)
diff --git a/m3u8/parse.go b/m3u8/parse.go
@@ -10,13 +10,14 @@ import (
 )
 
 const (
-	tagHead           = tagStart + "M3U"
-	tagVersion        = "#EXT-X-VERSION"
-	tagVariant        = "#EXT-X-STREAM-INF"
-	tagRendition      = "#EXT-X-MEDIA"
-	tagPlaylistType   = "#EXT-X-PLAYLIST-TYPE"  // RFC 8216, 4.4.3.5
-	tagTargetDuration = "#EXT-X-TARGETDURATION" // RFC 8216, 4.4.3.1
-	tagEndList        = "#EXT-X-ENDLIST"        // RFC 8216, 4.4.3.4
+	tagHead                = tagStart + "M3U"
+	tagVersion             = "#EXT-X-VERSION"
+	tagVariant             = "#EXT-X-STREAM-INF"
+	tagRendition           = "#EXT-X-MEDIA"
+	tagPlaylistType        = "#EXT-X-PLAYLIST-TYPE"        // RFC 8216, 4.4.3.5
+	tagTargetDuration      = "#EXT-X-TARGETDURATION"       // RFC 8216, 4.4.3.1
+	tagEndList             = "#EXT-X-ENDLIST"              // RFC 8216, 4.4.3.4
+	tagIndependentSegments = "#EXT-X-INDEPENDENT-SEGMENTS" // RFC 8216, 4.3.5.1
 )
 
 func ParsePlaylist(rd io.Reader) (*Playlist, error) {
@@ -46,6 +47,8 @@ func ParsePlaylist(rd io.Reader) (*Playlist, error) {
 				if err != nil {
 					return p, fmt.Errorf("parse playlist version: %w", err)
 				}
+			case tagIndependentSegments:
+				p.IndependentSegments = true
 			case tagVariant:
 				variant, err := parseVariant(lex.items)
 				if err != nil {
@@ -260,7 +263,7 @@ func parseRendition(items chan item) (*Rendition, error) {
 		case "CHARACTERISTICS":
 			rend.Characteristics = strings.Split(it.val, ",")
 		case "CHANNELS":
-			rend.Channels = strings.Split(it.val, "/")
+			rend.Channels = strings.Split(strings.Trim(it.val, `"`), "/")
 		default:
 			return nil, fmt.Errorf("unknown rendition attribute %s", attr.val)
 		}
diff --git a/m3u8/write.go b/m3u8/write.go
@@ -18,6 +18,9 @@ func Encode(w io.Writer, p *Playlist) error {
 	if p.Type != PlaylistNone {
 		fmt.Fprintf(w, "%s:%s\n", tagPlaylistType, p.Type)
 	}
+	if p.IndependentSegments {
+		fmt.Fprintln(w, tagIndependentSegments)
+	}
 	if p.TargetDuration > 0 {
 		fmt.Fprintf(w, "%s:%d\n", tagTargetDuration, p.TargetDuration/time.Second)
 	}
@@ -36,19 +39,73 @@ func Encode(w io.Writer, p *Playlist) error {
 		fmt.Fprintln(w, seg.URI)
 	}
 
+	for _, r := range p.Media {
+		if r.Name == "" {
+			return fmt.Errorf("empty name")
+		}
+		fmt.Fprintf(w, tagRendition+":")
+		// TODO(otl): use string slice, then strings.Join(s, ",")
+		// then we don't worry about errors from w.Write
+		fmt.Fprintf(w, "NAME=%q,", r.Name)
+		rname := fmt.Sprintf("rendition %s", r.Name)
+		if r.Type > MediaClosedCaptions {
+			return fmt.Errorf("%s: unknown type %s", rname, r.Type)
+		}
+		fmt.Fprintf(w, "TYPE=%s,", r.Type)
+		if r.URI != "" {
+			fmt.Fprintf(w, "URI=%q,", r.URI)
+		}
+		if r.Group == "" {
+			return fmt.Errorf("%s: empty group", rname)
+		}
+		fmt.Fprintf(w, "GROUP-ID=%q,", r.Group)
+		if r.Language != "" {
+			fmt.Fprintf(w, "LANGUAGE=%q,", r.Language)
+		}
+		if r.AssocLanguage != "" {
+			fmt.Fprintf(w, "ASSOC-LANGUAGE=%q,", r.AssocLanguage)
+		}
+		if r.Default {
+			fmt.Fprint(w, "DEFAULT=YES,")
+		}
+		if r.AutoSelect {
+			fmt.Fprint(w, "AUTOSELECT=YES,")
+		}
+		if r.Forced {
+			fmt.Fprint(w, "FORCED=YES,")
+		}
+
+		if r.Type != MediaClosedCaptions && r.InstreamID != nil {
+			return fmt.Errorf("%s: instream-id set but type is %s", rname, r.Type)
+		}
+		if r.Type == MediaClosedCaptions {
+			if r.InstreamID == nil {
+				return fmt.Errorf("%s: nil instream-id", rname)
+			}
+			fmt.Fprintf(w, "INSTREAM-ID=%q,", r.InstreamID)
+		}
+		if len(r.Characteristics) > 0 {
+			fmt.Fprintf(w, "CHARACTERISTICS=%q,", strings.Join(r.Characteristics, ","))
+		}
+		if len(r.Channels) > 0 {
+			fmt.Fprintf(w, "CHANNELS=%q,", strings.Join(r.Channels, "/"))
+		}
+		fmt.Fprintln(w)
+	}
+
 	for _, v := range p.Variants {
 		fmt.Fprint(w, tagVariant+":")
 		if v.Bandwidth > 0 {
 			fmt.Fprintf(w, "BANDWIDTH=%d,", v.Bandwidth)
 		}
 		if v.AverageBandwidth > 0 {
-			fmt.Fprintf(w, "AVERAGE-BANDWIDTH=%d", v.AverageBandwidth)
+			fmt.Fprintf(w, "AVERAGE-BANDWIDTH=%d,", v.AverageBandwidth)
 		}
 		if len(v.Codecs) > 0 {
 			fmt.Fprintf(w, "CODECS=%q,", strings.Join(v.Codecs, ","))
 		}
 		if v.Resolution != [2]int{0, 0} {
-			fmt.Fprintf(w, "RESOLUTION=%dx%d", v.Resolution[0], v.Resolution[1])
+			fmt.Fprintf(w, "RESOLUTION=%dx%d,", v.Resolution[0], v.Resolution[1])
 		}
 		fmt.Fprintln(w)
 		fmt.Fprintln(w, v.URI)