diff --git a/src/components/htmlvideoplayer/plugin.js b/src/components/htmlvideoplayer/plugin.js
index d25b49163b..ca93034260 100644
--- a/src/components/htmlvideoplayer/plugin.js
+++ b/src/components/htmlvideoplayer/plugin.js
@@ -188,6 +188,8 @@ define(['browser', 'require', 'events', 'apphost', 'loading', 'dom', 'playbackMa
         var currentAssRenderer;
         var customTrackIndex = -1;
 
+        var currentTrackOffset;
+
         var videoSubtitlesElem;
         var currentTrackEvents;
 
@@ -543,6 +545,65 @@ define(['browser', 'require', 'events', 'apphost', 'loading', 'dom', 'playbackMa
             setCurrentTrackElement(index);
         };
 
+        self.setSubtitleOffset = function(offset) {
+
+            var offsetValue = parseFloat(offset);
+            var videoElement = self._mediaElement;
+            var mediaStreamTextTracks = getMediaStreamTextTracks(self._currentPlayOptions.mediaSource);
+
+            Array.from(videoElement.textTracks)
+            .filter(trackElement => {
+                if (customTrackIndex === -1 ) {
+                    // get showing .vtt textTacks
+                    return trackElement.mode === 'showing';
+                } else {
+                    // get current .ass textTrack
+                    return ("textTrack" + customTrackIndex) === trackElement.id;
+                }
+            })
+            .forEach(trackElement => {
+
+                var track = mediaStreamTextTracks.filter(stream => {
+                    return ("textTrack" + stream.Index) === trackElement.id;
+                })[0];
+
+                if(track) {
+                    offsetValue = updateCurrentTrackOffset(offsetValue);
+                    var format = (track.Codec || '').toLowerCase();
+                    if (format !== 'ass' && format !== 'ssa') {
+                        setVttSubtitleOffset(trackElement, offsetValue);
+                    }
+                } else {
+                    console.log("No available track, cannot apply offset : " + offsetValue);
+                }
+
+            });
+        };
+
+        function updateCurrentTrackOffset(offsetValue) {
+
+            var relativeOffset = offsetValue;
+            var newTrackOffset = offsetValue;
+            if(currentTrackOffset){
+                relativeOffset -= currentTrackOffset;
+            }
+            currentTrackOffset = newTrackOffset;
+            // relative to currentTrackOffset
+            return relativeOffset;
+        }
+
+        function setVttSubtitleOffset(currentTrack, offsetValue) {
+
+            if(currentTrack.cues) {
+                Array.from(currentTrack.cues)
+                .forEach(cue => {
+                    cue.startTime -= offsetValue;
+                    cue.endTime -= offsetValue;
+                });
+            }
+
+        }
+
         function isAudioStreamSupported(stream, deviceProfile) {
 
             var codec = (stream.Codec || '').toLowerCase();
@@ -1167,6 +1228,11 @@ define(['browser', 'require', 'events', 'apphost', 'loading', 'dom', 'playbackMa
 
         function updateSubtitleText(timeMs) {
 
+            // handle offset for ass tracks
+            if(currentTrackOffset) {
+                timeMs += (currentTrackOffset * 1000);
+            }
+
             var clock = currentClock;
             if (clock) {
                 try {
diff --git a/src/components/playback/playbackmanager.js b/src/components/playback/playbackmanager.js
index 33b0b2b793..1588be5d22 100644
--- a/src/components/playback/playbackmanager.js
+++ b/src/components/playback/playbackmanager.js
@@ -1635,6 +1635,28 @@ define(['events', 'datetime', 'appSettings', 'itemHelper', 'pluginManager', 'pla
             getPlayerData(player).subtitleStreamIndex = index;
         };
 
+        self.supportSubtitleOffset = function(player) {
+            player = player || self._currentPlayer;
+            return 'setSubtitleOffset' in player;
+        }
+
+        self.isSubtitleStreamExternal = function(index, player) {
+            var stream = getSubtitleStream(player, index);
+            return stream ? getDeliveryMethod(stream) === 'External' : false;
+        }
+
+        self.setSubtitleOffset = function (sliderValue, player) {
+            player = player || self._currentPlayer;
+            player.setSubtitleOffset(self.getOffsetFromSliderValue(sliderValue));
+        };
+
+        self.getOffsetFromSliderValue = function(value) {
+            var offset = (value - 50) / 50;
+            // multiply by offset min/max range value (-x to +x) :
+            offset *= 30;
+            return offset.toFixed(1);
+        };
+
         self.seek = function (ticks, player) {
 
             ticks = Math.max(0, ticks);
diff --git a/src/controllers/videoosd.js b/src/controllers/videoosd.js
index c9befe03c5..00ce862f23 100644
--- a/src/controllers/videoosd.js
+++ b/src/controllers/videoosd.js
@@ -280,6 +280,7 @@ define(["playbackManager", "dom", "inputmanager", "datetime", "itemHelper", "med
                 btnFastForward.disabled = true;
                 btnRewind.disabled = true;
                 view.querySelector(".btnSubtitles").classList.add("hide");
+                view.querySelector(".subtitleSyncSliderContainer").classList.add("hide");
                 view.querySelector(".btnAudio").classList.add("hide");
                 view.querySelector(".osdTitle").innerHTML = "";
                 view.querySelector(".osdMediaInfo").innerHTML = "";
@@ -295,8 +296,23 @@ define(["playbackManager", "dom", "inputmanager", "datetime", "itemHelper", "med
 
             if (playbackManager.subtitleTracks(player).length) {
                 view.querySelector(".btnSubtitles").classList.remove("hide");
+
+                if(playbackManager.supportSubtitleOffset()) {
+                    var index = playbackManager.getSubtitleStreamIndex(player);
+                    // if there is an external subtitle stream enabled
+                    if(index !== -1  && playbackManager.isSubtitleStreamExternal(index, player)){
+                        // show subtitle sync slider
+                        subtitleSyncSliderContainer.classList.remove("hide");
+                    }else{
+                        // hide subtitle sync slider
+                        subtitleSyncSliderContainer.classList.add("hide");
+                    }
+                }
+
             } else {
                 view.querySelector(".btnSubtitles").classList.add("hide");
+                // hide subtitle sync slider
+                subtitleSyncSliderContainer.classList.add("hide");
             }
 
             if (playbackManager.audioTracks(player).length > 1) {
@@ -1008,6 +1024,28 @@ define(["playbackManager", "dom", "inputmanager", "datetime", "itemHelper", "med
                     if (index !== currentIndex) {
                         playbackManager.setSubtitleStreamIndex(index, player);
                     }
+                    return id;
+
+                }).then(function (id) {
+                    var index = parseInt(id);
+                    // on subtitle stream change
+                    if (playbackManager.supportSubtitleOffset() && index !== currentIndex) {
+
+                        /// if there is an external subtitle stream enabled
+                        if (index !== -1 && playbackManager.isSubtitleStreamExternal(index, player)){
+
+                            // set default offset to '0' (slider's middle value)
+                            var subtitleSyncSliderMiddleValue = 50;
+                            subtitleSyncSlider.value = subtitleSyncSliderMiddleValue.toString();
+                            playbackManager.setSubtitleOffset(subtitleSyncSliderMiddleValue, player);
+
+                            // show subtitle sync slider
+                            subtitleSyncSliderContainer.classList.remove("hide");
+                        } else {
+                            // hide subtitle sync slider
+                            subtitleSyncSliderContainer.classList.add("hide");
+                        }
+                    }
                 });
             });
         }
@@ -1146,6 +1184,8 @@ define(["playbackManager", "dom", "inputmanager", "datetime", "itemHelper", "med
         var programStartDateMs = 0;
         var programEndDateMs = 0;
         var playbackStartTimeTicks = 0;
+        var subtitleSyncSlider = view.querySelector(".subtitleSyncSlider");
+        var subtitleSyncSliderContainer = view.querySelector(".subtitleSyncSliderContainer");
         var nowPlayingVolumeSlider = view.querySelector(".osdVolumeSlider");
         var nowPlayingVolumeSliderContainer = view.querySelector(".osdVolumeSliderContainer");
         var nowPlayingPositionSlider = view.querySelector(".osdPositionSlider");
@@ -1268,6 +1308,21 @@ define(["playbackManager", "dom", "inputmanager", "datetime", "itemHelper", "med
         nowPlayingVolumeSlider.addEventListener("touchmove", function () {
             playbackManager.setVolume(this.value, currentPlayer);
         });
+
+        subtitleSyncSlider.addEventListener("change", function () {
+            playbackManager.setSubtitleOffset(this.value, currentPlayer);
+        });
+        subtitleSyncSlider.addEventListener("touchmove", function () {
+            playbackManager.setSubtitleOffset(this.value, currentPlayer);
+        });
+
+        subtitleSyncSlider.getBubbleHtml = function (value) {
+            var newOffset = playbackManager.getOffsetFromSliderValue(value);
+            return '<h1 class="sliderBubbleText">' +
+            (newOffset > 0 ? "+" : "") + parseFloat(newOffset) + "s" +
+            "</h1>";
+        };
+
         nowPlayingPositionSlider.addEventListener("change", function () {
             var player = currentPlayer;
 
diff --git a/src/css/videoosd.css b/src/css/videoosd.css
index bd24e41309..5151f87d63 100644
--- a/src/css/videoosd.css
+++ b/src/css/videoosd.css
@@ -144,6 +144,13 @@
     flex-grow: 1
 }
 
+.subtitleSyncSliderContainer {
+    width: 12em;
+    -webkit-box-flex: 1;
+    -webkit-flex-grow: 1;
+    flex-grow: 1
+}
+
 .osdMediaInfo,
 .volumeButtons {
     display: -webkit-box;
diff --git a/src/videoosd.html b/src/videoosd.html
index e70adbe39c..d5c117a4d4 100644
--- a/src/videoosd.html
+++ b/src/videoosd.html
@@ -59,6 +59,13 @@
                 <button is="paper-icon-button-light" class="btnSubtitles hide autoSize" title="${Subtitles}">
                     <i class="xlargePaperIconButton md-icon">&#xE01C;</i>
                 </button>
+
+                <div class="subttitleSyncButtons hide-mouse-idle-tv">
+                    <div class="sliderContainer subtitleSyncSliderContainer">
+                        <input is="emby-slider" type="range" step="1" min="0" max="100" value="50" class="subtitleSyncSlider" />
+                    </div>
+                </div>
+
                 <button is="paper-icon-button-light" class="btnVideoOsdSettings hide autoSize" title="${Settings}">
                     <i class="largePaperIconButton md-icon">&#xE8B8;</i>
                 </button>