Add support for tag EXT-X-DEFINE (#167)

Author: bbert

parse.ts

@@ -73,6 +73,7 @@ function getTagCategory(tagName: string): TagCategory {
       return 'MasterPlaylist';
     case 'EXT-X-INDEPENDENT-SEGMENTS':
     case 'EXT-X-START':
+    case 'EXT-X-DEFINE':
       return 'MediaorMasterPlaylist';
     default:
       return 'Unknown';
@@ -247,6 +248,7 @@ function parseTagParam(name: string, param): TagParam {
     case 'EXT-X-PRELOAD-HINT':
     case 'EXT-X-RENDITION-REPORT':
     case 'EXT-X-SKIP':
+    case 'EXT-X-DEFINE':
       return [null, parseAttributeList(param)];
     case 'EXTINF':
       return [parseEXTINF(param), null];
@@ -477,6 +479,11 @@ function parseMasterPlaylist(lines: Line[], params: Record<string, any>): Master
         utils.INVALIDPLAYLIST('EXT-X-START: TIME-OFFSET attribute is REQUIRED');
       }
       playlist.start = {offset: attributes['TIME-OFFSET'], precise: attributes['PRECISE'] || false};
+    } else if (name === 'EXT-X-DEFINE') {
+      if (!playlist.defines) {
+        playlist.defines = [];
+      }
+      playlist.defines.push(attributes);
     }
   }
   if (variantIsScored) {
@@ -775,6 +782,11 @@ function parseMediaPlaylist(lines: Line[], params: Record<string, any>): MediaPl
       }
       prefetchFound = true;
       segmentStart = -1;
+    } else if (name === 'EXT-X-DEFINE') {
+      if (!playlist.defines) {
+        playlist.defines = [];
+      }
+      playlist.defines.push(attributes);
     } else if (typeof line === 'string') {
       // uri
       if (segmentStart === -1) {

stringify.ts

@@ -490,6 +490,15 @@ function buildParts(lines: LineArray, parts: PartialSegment[]) {
   return hint;
 }
 
+function buildDefines(define: Record<string, string>) {
+  const attrs: string[] = [];
+  for (var attr in define) {
+    attrs.push(`${attr}="${define[attr]}"`);
+  }
+  return `#EXT-X-DEFINE:${attrs.join(',')}`;
+}
+
+
 function stringify(playlist: MasterPlaylist | MediaPlaylist, postProcess?: PostProcess): string {
   utils.PARAMCHECK(playlist);
   utils.ASSERT('Not a playlist', playlist.type === 'playlist');
@@ -504,6 +513,11 @@ function stringify(playlist: MasterPlaylist | MediaPlaylist, postProcess?: PostP
   if (playlist.start) {
     lines.push(`#EXT-X-START:TIME-OFFSET=${buildDecimalFloatingNumber(playlist.start.offset)}${playlist.start.precise ? ',PRECISE=YES' : ''}`);
   }
+  if (playlist.defines) {
+    for (const session of playlist.defines) {
+      lines.push(buildDefines(session));
+    }
+  }
   if (playlist.isMasterPlaylist) {
     buildMasterPlaylist(lines, playlist, postProcess);
   } else {

types.ts

@@ -277,14 +277,16 @@ class Playlist extends Data {
   independentSegments: boolean;
   start?: { offset: number; precise: boolean };
   source?: string;
+  defines?: Record<string, string>[];
 
   constructor({
     isMasterPlaylist, // required
     uri,
     version,
     independentSegments = false,
     start,
-    source
+    source,
+    defines,
   }: Partial<Playlist> & { isMasterPlaylist: boolean }) {
     super('playlist');
     utils.PARAMCHECK(isMasterPlaylist);
@@ -294,6 +296,7 @@ class Playlist extends Data {
     this.independentSegments = independentSegments;
     this.start = start;
     this.source = source;
+    this.defines = defines;
   }
 }