fix: Suppress Infinity duration on Android Chrome before playback (#3476)

HTML5 tech will return NaN instead of Infinity if playback has not started. Fires a durationupdate event once the reported duration can be believed if the duration is still Infinity, so controls can update.

Fixes #3079.

src/js/tech/html5.js

@@ -428,7 +428,30 @@ class Html5 extends Tech {
    * @return {Number}
    */
   duration() {
-    return this.el_.duration || 0;
+    // Android Chrome will report duration as Infinity for VOD HLS until after
+    // playback has started, which triggers the live display erroneously.
+    // Return NaN if playback has not started and trigger a durationupdate once
+    // the duration can be reliably known.
+    if (this.el_.duration === Infinity &&
+      browser.IS_ANDROID && browser.IS_CHROME) {
+      if (this.el_.currentTime === 0) {
+        // Wait for the first `timeupdate` with currentTime > 0 - there may be
+        // several with 0
+        const checkProgress = () => {
+          if (this.el_.currentTime > 0) {
+            // Trigger durationchange for genuinely live video
+            if (this.el_.duration === Infinity) {
+              this.trigger('durationchange');
+            }
+            this.off(this.player_, 'timeupdate', checkProgress);
+          }
+        };
+
+        this.on(this.player_, 'timeupdate', checkProgress);
+        return NaN;
+      }
+    }
+    return this.el_.duration || NaN;
   }
 
   /**

test/unit/tech/html5.test.js

@@ -562,3 +562,22 @@ QUnit.test('Exception in play promise should be caught', function() {
 
   tech.el_ = oldEl;
 });
+
+test('When Android Chrome reports Infinity duration with currentTime 0, return NaN', function() {
+  const oldIsAndroid = browser.IS_ANDROID;
+  const oldIsChrome = browser.IS_CHROME;
+  const oldEl = tech.el_;
+
+  browser.IS_ANDROID = true;
+  browser.IS_CHROME = true;
+
+  tech.el_ = {
+    duration: Infinity,
+    currentTime: 0
+  };
+  ok(Number.isNaN(tech.duration()), 'returned NaN with currentTime 0');
+
+  browser.IS_ANDROID = oldIsAndroid;
+  browser.IS_CHROME = oldIsChrome;
+  tech.el_ = oldEl;
+});