feat(HLS): Add support for EXT-X-SESSION-KEY tag

shaka-project · Nov 6, 2022 · 21a877a · 21a877a
1 parent 59d4360
commit 21a877a
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Showing 2 changed files with 354 additions and 4 deletions.
diff --git a/lib/hls/hls_parser.js b/lib/hls/hls_parser.js
@@ -659,6 +659,9 @@ shaka.hls.HlsParser = class {
       /** @type {!Array.<!shaka.hls.Tag>} */
       const imageTags = Utils.filterTagsByName(
           playlist.tags, 'EXT-X-IMAGE-STREAM-INF');
+      /** @type {!Array.<!shaka.hls.Tag>} */
+      const sessionKeyTags = Utils.filterTagsByName(
+          playlist.tags, 'EXT-X-SESSION-KEY');
 
       this.parseCodecs_(variantTags);
 
@@ -691,7 +694,7 @@ shaka.hls.HlsParser = class {
       // start time from audio/video streams and reuse for text streams.
       this.createStreamInfosFromMediaTags_(mediaTags);
       this.parseClosedCaptions_(mediaTags);
-      variants = this.createVariantsForTags_(variantTags);
+      variants = this.createVariantsForTags_(variantTags, sessionKeyTags);
       textStreams = this.parseTexts_(mediaTags);
       imageStreams = await this.parseImages_(imageTags);
     }
@@ -964,10 +967,12 @@ shaka.hls.HlsParser = class {
 
   /**
    * @param {!Array.<!shaka.hls.Tag>} tags Variant tags from the playlist.
+   * @param {!Array.<!shaka.hls.Tag>} sessionKeyTags EXT-X-SESSION-KEY tags
+   * from the playlist.
    * @return {!Array.<!shaka.extern.Variant>}
    * @private
    */
-  createVariantsForTags_(tags) {
+  createVariantsForTags_(tags, sessionKeyTags) {
     // Create variants for each variant tag.
     const allVariants = tags.map((tag) => {
       const frameRate = tag.getAttributeValue('FRAME-RATE');
@@ -985,14 +990,56 @@ shaka.hls.HlsParser = class {
       goog.asserts.assert(streamInfos.audio.length ||
           streamInfos.video.length, 'We should have created a stream!');
 
+      const drmInfos = [];
+      const keyIds = new Set();
+
+      if (sessionKeyTags.length > 0) {
+        const characteristics = tag.getAttributeValue('CHARACTERISTICS');
+        for (const drmTag of sessionKeyTags) {
+          const drmCharacteristics =
+              drmTag.getAttributeValue('CHARACTERISTICS');
+          if ((characteristics && !drmCharacteristics) ||
+              (!characteristics && drmCharacteristics) ||
+              (drmCharacteristics && characteristics &&
+              !characteristics.includes(drmCharacteristics))) {
+            continue;
+          }
+          const method = drmTag.getRequiredAttrValue('METHOD');
+          if (method != 'NONE' && method != 'AES-128') {
+            // According to the HLS spec, KEYFORMAT is optional and implicitly
+            // defaults to "identity".
+            // https://datatracker.ietf.org/doc/html/draft-pantos-hls-rfc8216bis-11#section-4.4.4.4
+            const keyFormat =
+                drmTag.getAttributeValue('KEYFORMAT') || 'identity';
+            const drmParser =
+                shaka.hls.HlsParser.KEYFORMATS_TO_DRM_PARSERS_[keyFormat];
+
+            const drmInfo = drmParser ?
+                drmParser(drmTag, /* mimeType= */ '') : null;
+            if (drmInfo) {
+              if (drmInfo.keyIds) {
+                for (const keyId of drmInfo.keyIds) {
+                  keyIds.add(keyId);
+                }
+              }
+              drmInfos.push(drmInfo);
+            } else {
+              shaka.log.warning('Unsupported HLS KEYFORMAT', keyFormat);
+            }
+          }
+        }
+      }
+
       return this.createVariants_(
           streamInfos.audio,
           streamInfos.video,
           bandwidth,
           width,
           height,
           frameRate,
-          videoRange);
+          videoRange,
+          drmInfos,
+          keyIds);
     });
     let variants = allVariants.reduce(shaka.util.Functional.collapseArrays, []);
     // Filter out null variants.
@@ -1234,11 +1281,14 @@ shaka.hls.HlsParser = class {
    * @param {?string} height
    * @param {?string} frameRate
    * @param {?string} videoRange
+   * @param {!Array.<shaka.extern.DrmInfo>} drmInfos
+   * @param {!Set.<string>} keyIds
    * @return {!Array.<!shaka.extern.Variant>}
    * @private
    */
   createVariants_(
-      audioInfos, videoInfos, bandwidth, width, height, frameRate, videoRange) {
+      audioInfos, videoInfos, bandwidth, width, height, frameRate, videoRange,
+      drmInfos, keyIds) {
     const ContentType = shaka.util.ManifestParserUtils.ContentType;
     const DrmEngine = shaka.media.DrmEngine;
 
@@ -1264,7 +1314,15 @@ shaka.hls.HlsParser = class {
     for (const audioInfo of audioInfos) {
       for (const videoInfo of videoInfos) {
         const audioStream = audioInfo ? audioInfo.stream : null;
+        if (audioStream) {
+          audioStream.drmInfos = drmInfos;
+          audioStream.keyIds = keyIds;
+        }
         const videoStream = videoInfo ? videoInfo.stream : null;
+        if (videoStream) {
+          videoStream.drmInfos = drmInfos;
+          videoStream.keyIds = keyIds;
+        }
         const audioDrmInfos = audioInfo ? audioInfo.stream.drmInfos : null;
         const videoDrmInfos = videoInfo ? videoInfo.stream.drmInfos : null;
         const videoStreamUri =