diff --git a/src/plugins/htmlVideoPlayer/plugin.js b/src/plugins/htmlVideoPlayer/plugin.js index f2a2b8d30b..8902b9cf25 100644 --- a/src/plugins/htmlVideoPlayer/plugin.js +++ b/src/plugins/htmlVideoPlayer/plugin.js @@ -620,6 +620,28 @@ function tryRemoveElement(elem) { return relativeOffset; } + /** + * @private + * These browsers will not clear the existing active cue when setting an offset + * for native TextTracks. + * Any previous text tracks that are on the screen when the offset changes will + * remain next to the new tracks until they reach the new offset's instance of the track. + */ + requiresHidingActiveCuesOnOffsetChange() { + return !!browser.firefox; + } + + /** + * @private + */ + hideTextTrackActiveCues(currentTrack) { + if (currentTrack.activeCues) { + Array.from(currentTrack.activeCues).forEach((cue) => { + cue.text = ''; + }); + } + } + /** * @private */ @@ -629,6 +651,9 @@ function tryRemoveElement(elem) { if (offsetValue === 0) { return; } + if (this.requiresHidingActiveCuesOnOffsetChange()) { + this.hideTextTrackActiveCues(currentTrack); + } Array.from(currentTrack.cues) .forEach(function (cue) { cue.startTime -= offsetValue;