From 3fd87fec09671e45affea864db0551d6f45fd2a6 Mon Sep 17 00:00:00 2001
From: jony89 <ariel@emath.co.il>
Date: Sat, 18 Jan 2020 12:05:38 +0200
Subject: [PATCH] fix: computeLivePosition minimum value of media.currentTime

---
 src/controller/base-stream-controller.js   |  3 ++-
 src/controller/stream-controller.js        |  4 ++--
 tests/unit/controller/stream-controller.js | 26 ++++++++++++++++++++++
 3 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/src/controller/base-stream-controller.js b/src/controller/base-stream-controller.js
index ae3348d7cd1..ab3b066da18 100644
--- a/src/controller/base-stream-controller.js
+++ b/src/controller/base-stream-controller.js
@@ -128,6 +128,7 @@ export default class BaseStreamController extends TaskLoop {
 
   computeLivePosition (sliding, levelDetails) {
     let targetLatency = this.config.liveSyncDuration !== undefined ? this.config.liveSyncDuration : this.config.liveSyncDurationCount * levelDetails.targetduration;
-    return sliding + Math.max(0, levelDetails.totalduration - targetLatency);
+    const currentTime = this.media ? this.media.currentTime : null;
+    return Math.max(sliding + Math.max(0, levelDetails.totalduration - targetLatency), currentTime);
   }
 }
diff --git a/src/controller/stream-controller.js b/src/controller/stream-controller.js
index 701acc58b2f..d0869e372d0 100644
--- a/src/controller/stream-controller.js
+++ b/src/controller/stream-controller.js
@@ -280,9 +280,9 @@ class StreamController extends BaseStreamController {
 
     if (bufferEnd < Math.max(start - config.maxFragLookUpTolerance, end - maxLatency)) {
       let liveSyncPosition = this.liveSyncPosition = this.computeLivePosition(start, levelDetails);
-      logger.log(`buffer end: ${bufferEnd.toFixed(3)} is located too far from the end of live sliding playlist, reset currentTime to : ${liveSyncPosition.toFixed(3)}`);
       bufferEnd = liveSyncPosition;
-      if (media && !media.paused && media.readyState && media.duration > liveSyncPosition) {
+      if (media && !media.paused && media.readyState && media.duration > liveSyncPosition && liveSyncPosition > media.currentTime) {
+        logger.log(`buffer end: ${bufferEnd.toFixed(3)} is located too far from the end of live sliding playlist, reset currentTime to : ${liveSyncPosition.toFixed(3)}`);
         media.currentTime = liveSyncPosition;
       }
 
diff --git a/tests/unit/controller/stream-controller.js b/tests/unit/controller/stream-controller.js
index 3df11e27ca1..428b25a4bef 100644
--- a/tests/unit/controller/stream-controller.js
+++ b/tests/unit/controller/stream-controller.js
@@ -305,4 +305,30 @@ describe('StreamController', function () {
       });
     });
   });
+
+  describe('computeLivePosition', function () {
+    it('should return the current live sync position according to liveSyncDuration', function () {
+      streamController.config.liveSyncDuration = 2;
+      const levelDetails = { totalduration: 20 };
+      const liveSyncPosition = streamController.computeLivePosition(8, levelDetails);
+      expect(liveSyncPosition).to.equal(26);
+    });
+
+    it('should return the current live sync position according to liveSyncDurationCount', function () {
+      streamController.config.liveSyncDurationCount = 2;
+      const levelDetails = { totalduration: 20, targetduration: 0.5 };
+      const liveSyncPosition = streamController.computeLivePosition(8, levelDetails);
+      expect(liveSyncPosition).to.equal(27);
+    });
+
+    it('should not return value that is less than the video current time', function () {
+      streamController.media = {
+        currentTime: 25
+      };
+      streamController.config.liveSyncDuration = 1;
+      const levelDetails = { totalduration: 14 };
+      const liveSyncPosition = streamController.computeLivePosition(8, levelDetails);
+      expect(liveSyncPosition).to.equal(25);
+    });
+  });
 });