feat(HLS): Add support to blocking playlist reload by adding the CAN-…

…BLOCK-RELOAD=YES (shaka-project#5279)
theodab · Jun 12, 2023 · 090554b · 090554b
1 parent 9dddc09
commit 090554b
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Showing 2 changed files with 32 additions and 34 deletions.
diff --git a/lib/hls/hls_parser.js b/lib/hls/hls_parser.js
@@ -349,16 +349,18 @@ shaka.hls.HlsParser = class {
         // 'EXT-X-SKIP' tag in the media playlist.
         queryData.add('_HLS_skip', 'YES');
       }
-      if (streamInfo.nextMediaSequence >= 0) {
-        // Indicates that the server must hold the request until a Playlist
-        // contains a Media Segment with Media Sequence
-        queryData.add('_HLS_msn', String(streamInfo.nextMediaSequence));
-      }
-      if (streamInfo.nextPart >= 0) {
-        // Indicates, in combination with _HLS_msn, that the server must hold
-        // the request until a Playlist contains Partial Segment N of Media
-        // Sequence Number M or later.
-        queryData.add('_HLS_part', String(streamInfo.nextPart));
+      if (streamInfo.canBlockReload) {
+        if (streamInfo.nextMediaSequence >= 0) {
+          // Indicates that the server must hold the request until a Playlist
+          // contains a Media Segment with Media Sequence
+          queryData.add('_HLS_msn', String(streamInfo.nextMediaSequence));
+        }
+        if (streamInfo.nextPart >= 0) {
+          // Indicates, in combination with _HLS_msn, that the server must hold
+          // the request until a Playlist contains Partial Segment N of Media
+          // Sequence Number M or later.
+          queryData.add('_HLS_part', String(streamInfo.nextPart));
+        }
       }
       if (queryData.getCount()) {
         uriObj.setQueryData(queryData);
@@ -1960,6 +1962,7 @@ shaka.hls.HlsParser = class {
       maxTimestamp: 0,
       mediaSequenceToStartTime: new Map(),
       canSkipSegments: false,
+      canBlockReload: false,
       hasEndList: false,
       firstSequenceNumber: -1,
       nextMediaSequence: -1,
@@ -2007,6 +2010,7 @@ shaka.hls.HlsParser = class {
       streamInfo.minTimestamp = realStreamInfo.minTimestamp;
       streamInfo.maxTimestamp = realStreamInfo.maxTimestamp;
       streamInfo.canSkipSegments = realStreamInfo.canSkipSegments;
+      streamInfo.canBlockReload = realStreamInfo.canBlockReload;
       streamInfo.hasEndList = realStreamInfo.hasEndList;
       streamInfo.mediaSequenceToStartTime =
           realStreamInfo.mediaSequenceToStartTime;
@@ -2297,6 +2301,8 @@ shaka.hls.HlsParser = class {
         playlist.tags, 'EXT-X-SERVER-CONTROL');
     const canSkipSegments = serverControlTag ?
           serverControlTag.getAttribute('CAN-SKIP-UNTIL') != null : false;
+    const canBlockReload = serverControlTag ?
+          serverControlTag.getAttribute('CAN-BLOCK-RELOAD') != null : false;
 
     const mediaSequenceNumber = shaka.hls.Utils.getFirstTagWithNameAsNumber(
         playlist.tags, 'EXT-X-MEDIA-SEQUENCE', 0);
@@ -2320,6 +2326,7 @@ shaka.hls.HlsParser = class {
       minTimestamp: firstStartTime,
       maxTimestamp: lastEndTime,
       canSkipSegments,
+      canBlockReload,
       hasEndList: false,
       firstSequenceNumber: -1,
       nextMediaSequence,
@@ -3695,6 +3702,7 @@ shaka.hls.HlsParser = class {
  *   maxTimestamp: number,
  *   mediaSequenceToStartTime: !Map.<number, number>,
  *   canSkipSegments: boolean,
+ *   canBlockReload: boolean,
  *   hasEndList: boolean,
  *   firstSequenceNumber: number,
  *   nextMediaSequence: number,
@@ -3727,6 +3735,10 @@ shaka.hls.HlsParser = class {
  * @property {boolean} canSkipSegments
  *   True if the server supports delta playlist updates, and we can send a
  *   request for a playlist that can skip older media segments.
+ * @property {boolean} canBlockReload
+ *   True if the server supports blocking playlist reload, and we can send a
+ *   request for a playlist that can block reload until some segments are
+ *   present.
  * @property {boolean} hasEndList
  *   True if the stream has an EXT-X-ENDLIST tag.
  * @property {number} firstSequenceNumber

diff --git a/test/hls/hls_live_unit.js b/test/hls/hls_live_unit.js
@@ -163,28 +163,14 @@ describe('HlsParser live', () => {
    * @param {shaka.extern.Manifest} manifest
    * @param {string} updatedMedia
    * @param {Array=} updatedReferences
-   * @param {?number=} sequenceNumber
    */
-  async function testUpdate(manifest, updatedMedia, updatedReferences=null,
-      sequenceNumber=null) {
+  async function testUpdate(manifest, updatedMedia, updatedReferences=null) {
     // Replace the entries with the updated values.
-    if (sequenceNumber == null) {
-      fakeNetEngine
-          .setResponseText('test:/video', updatedMedia)
-          .setResponseText('test:/redirected/video', updatedMedia)
-          .setResponseText('test:/video2', updatedMedia)
-          .setResponseText('test:/audio', updatedMedia);
-    } else {
-      fakeNetEngine
-          .setResponseText('test:/video?_HLS_msn=' + sequenceNumber,
-              updatedMedia)
-          .setResponseText('test:/redirected/video?_HLS_msn=' + sequenceNumber,
-              updatedMedia)
-          .setResponseText('test:/video2?_HLS_msn=' + sequenceNumber,
-              updatedMedia)
-          .setResponseText('test:/audio?_HLS_msn=' + sequenceNumber,
-              updatedMedia);
-    }
+    fakeNetEngine
+        .setResponseText('test:/video', updatedMedia)
+        .setResponseText('test:/redirected/video', updatedMedia)
+        .setResponseText('test:/video2', updatedMedia)
+        .setResponseText('test:/audio', updatedMedia);
 
     await delayForUpdatePeriod();
 
@@ -916,7 +902,7 @@ describe('HlsParser live', () => {
           '#EXT-X-TARGETDURATION:5\n',
           '#EXT-X-MEDIA-SEQUENCE:0\n',
           '#EXT-X-MAP:URI="init.mp4",BYTERANGE="616@0"\n',
-          '#EXT-X-SERVER-CONTROL:CAN-SKIP-UNTIL=60.0\n',
+          '#EXT-X-SERVER-CONTROL:CAN-BLOCK-RELOAD=YES,CAN-SKIP-UNTIL=60.0,\n',
           '#EXTINF:2,\n',
           'main.mp4\n',
           '#EXTINF:2,\n',
@@ -928,7 +914,7 @@ describe('HlsParser live', () => {
           '#EXT-X-TARGETDURATION:5\n',
           '#EXT-X-MAP:URI="init.mp4",BYTERANGE="616@0"\n',
           '#EXT-X-MEDIA-SEQUENCE:1\n',
-          '#EXT-X-SERVER-CONTROL:CAN-SKIP-UNTIL=60.0\n',
+          '#EXT-X-SERVER-CONTROL:CAN-BLOCK-RELOAD=YES,CAN-SKIP-UNTIL=60.0,\n',
           '#EXT-X-SKIP:SKIPPED-SEGMENTS=1\n',
           '#EXTINF:2,\n',
           'main2.mp4\n',
@@ -981,7 +967,7 @@ describe('HlsParser live', () => {
         // and ref1 should be in the SegmentReferences list.
         // ref3 should be appended to the SegmentReferences list.
         await testUpdate(
-            manifest, mediaWithSkippedSegments, [ref1, ref2, ref3], 2);
+            manifest, mediaWithSkippedSegments, [ref1, ref2, ref3]);
       });
 
       it('skips older segments with discontinuity', async () => {
@@ -1046,7 +1032,7 @@ describe('HlsParser live', () => {
         // and ref1,ref2 should be in the SegmentReferences list.
         // ref3,ref4 should be appended to the SegmentReferences list.
         await testUpdate(
-            manifest, mediaWithSkippedSegments2, [ref1, ref2, ref3, ref4], 3);
+            manifest, mediaWithSkippedSegments2, [ref1, ref2, ref3, ref4]);
       });
 
       it('updates encryption keys', async () => {