feat: trim beginning of demuxed VODs

Eyevinn · Aug 7, 2023 · 3ffa3dc · 3ffa3dc
1 parent a0689bf
commit 3ffa3dc
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Showing 2 changed files with 34 additions and 2 deletions.
diff --git a/index.js b/index.js
@@ -209,8 +209,19 @@ class HLSTruncateVod {
         let accDuration = 0;
         let prevAccDuration = 0;
         let pos = 0;
+        let startPos = 0;
+
+        if (this.startOffset) {
+          let accStartOffset = 0;
+          m3u.items.PlaylistItem.map((item => {
+            if (accStartOffset <= this.startOffset) {
+              accStartOffset += item.get('duration');
+              startPos++;
+            }
+          }));
+        }
 
-        m3u.items.PlaylistItem.map((item => {
+        m3u.items.PlaylistItem.slice(startPos).map((item => {
           if (accDuration <= this.durationAudio) {
             prevAccDuration = accDuration;
             accDuration += item.get('duration');
@@ -224,7 +235,7 @@ class HLSTruncateVod {
         if (this._similarSegItemDuration() && (accDuration - this.durationAudio) >= (this.durationAudio - prevAccDuration) && pos > 1) {
           pos--;
         }
-        this.audioSegments[audioGroupId][audioLang].items.PlaylistItem = m3u.items.PlaylistItem.slice(0, pos);
+        this.audioSegments[audioGroupId][audioLang].items.PlaylistItem = m3u.items.PlaylistItem.slice(startPos, startPos + pos);
         resolve();
       });
       parser.on('error', (err) => {

diff --git a/spec/hls_truncate_spec.js b/spec/hls_truncate_spec.js
@@ -194,6 +194,27 @@ describe("HLSTruncateVod,", () => {
           done();
         })
     });
+
+    it("can trim the beginning if start offset is requested", done => {
+      const mockVod = new HLSTruncateVod('http://mock.com/mock.m3u8', 30, { offset: 30 });
+
+      mockVod.load(mockMasterManifest, mockMediaManifest, mockAudioManifest)
+        .then(() => {
+          const bandwidths = mockVod.getBandwidths();
+          const manifest = mockVod.getMediaManifest(bandwidths[0]);
+          const lines = manifest.split("\n");
+          expect(lines[8]).toEqual("level1/seg_37.ts");
+          expect(lines[11]).toEqual("level1/seg_38.ts");
+          const duration = calcDuration(manifest);
+          expect(duration).toEqual(30.03);
+
+          const audioManifest = mockVod.getAudioManifest("aac", "en");
+          const audioLines = audioManifest.split("\n");
+          expect(audioLines[8]).toEqual("audio/seg_en_37.ts");
+          expect(audioLines[11]).toEqual("audio/seg_en_38.ts");
+          done();
+        })
+    });
   });
   describe("for Demuxed TS HLS Vods which have different segments durations,", () => {
     let mockMasterManifest;