diff --git a/app/common/timerange.cpp b/app/common/timerange.cpp
index 78df8b438..fc8d96c7d 100644
--- a/app/common/timerange.cpp
+++ b/app/common/timerange.cpp
@@ -58,6 +58,11 @@ TimeRange TimeRange::CombineWith(const TimeRange &a) const
   return Combine(a, *this);
 }
 
+bool TimeRange::Contains(const TimeRange &a) const
+{
+  return (a.in() >= in() && a.out() <= out());
+}
+
 bool TimeRange::Overlap(const TimeRange &a, const TimeRange &b)
 {
   return !(a.out() < b.in() || a.in() > b.out());
@@ -85,3 +90,43 @@ uint qHash(const TimeRange &r, uint seed)
 {
   return qHash(r.in(), seed) ^ qHash(r.out(), seed);
 }
+
+void TimeRangeList::InsertTimeRange(const TimeRange &range)
+{
+  for (int i=0;i<size();i++) {
+    const TimeRange& compare = at(i);
+
+    if (TimeRange::Overlap(range, compare)) {
+      replace(i, TimeRange::Combine(range, compare));
+      return;
+    }
+  }
+
+  append(range);
+}
+
+void TimeRangeList::RemoveTimeRange(const TimeRange &range)
+{
+  for (int i=0;i<size();i++) {
+    const TimeRange& compare = at(i);
+
+    if (range.Contains(compare)) {
+      // This element is entirely encompassed in this range, remove it
+      removeAt(i);
+      i--;
+    } else if (compare.Contains(range)) {
+      // The remove range is within this element, only choice is to split the element into two
+      TimeRange first(compare.in(), range.in());
+      TimeRange last(range.out(), compare.out());
+
+      replace(i, first);
+      append(last);
+    } else if (compare.in() < range.in() && compare.out() > range.in()) {
+      // This element's out point overlaps the range's in, we'll trim it
+      (*this)[i].set_out(range.in());
+    } else if (compare.in() < range.out() && compare.out() > range.out()) {
+      // This element's in point overlaps the range's out, we'll trim it
+      (*this)[i].set_in(range.out());
+    }
+  }
+}
diff --git a/app/common/timerange.h b/app/common/timerange.h
index fa239baed..99e565660 100644
--- a/app/common/timerange.h
+++ b/app/common/timerange.h
@@ -20,6 +20,7 @@ public:
 
   bool OverlapsWith(const TimeRange& a) const;
   TimeRange CombineWith(const TimeRange& a) const;
+  bool Contains(const TimeRange& a) const;
 
   static bool Overlap(const TimeRange& a, const TimeRange& b);
   static TimeRange Combine(const TimeRange &a, const TimeRange &b);
@@ -34,4 +35,14 @@ private:
 
 uint qHash(const TimeRange& r, uint seed);
 
+class TimeRangeList : public QList<TimeRange> {
+public:
+  TimeRangeList() = default;
+
+  void InsertTimeRange(const TimeRange& range);
+
+  void RemoveTimeRange(const TimeRange& range);
+
+};
+
 #endif // TIMERANGE_H
diff --git a/app/render/backend/audiorenderbackend.cpp b/app/render/backend/audiorenderbackend.cpp
index 0a2e09522..113d8f5f1 100644
--- a/app/render/backend/audiorenderbackend.cpp
+++ b/app/render/backend/audiorenderbackend.cpp
@@ -39,10 +39,7 @@ void AudioRenderBackend::InvalidateCache(const rational &start_range, const rati
   rational end_range_adj = qMin(GetSequenceLength(), end_range);
 
   // Add the range to the list
-  cache_queue_.append(TimeRange(start_range_adj, end_range_adj));
-
-  // Remove any overlaps so we don't render the same thing twice
-  ValidateRanges();
+  cache_queue_.InsertTimeRange(TimeRange(start_range_adj, end_range_adj));
 
   // Queue value update
   QueueValueUpdate();
@@ -87,26 +84,6 @@ NodeInput *AudioRenderBackend::GetDependentInput()
   return viewer_node()->samples_input();
 }
 
-void AudioRenderBackend::ValidateRanges()
-{
-  for (int i=0;i<cache_queue_.size();i++) {
-    const TimeRange& range1 = cache_queue_.at(i);
-
-    for (int j=0;j<cache_queue_.size();j++) {
-      const TimeRange& range2 = cache_queue_.at(j);
-
-      if (TimeRange::Overlap(range1, range2) && i != j) {
-        // Combine with the first range
-        cache_queue_[i] = TimeRange::Combine(range1, range2);
-
-        // Remove the second range
-        cache_queue_.removeAt(j);
-        j--;
-      }
-    }
-  }
-}
-
 QString AudioRenderBackend::CachePathName()
 {
   QDir this_cache_dir = QDir(GetMediaCacheLocation()).filePath(cache_id());
diff --git a/app/render/backend/audiorenderbackend.h b/app/render/backend/audiorenderbackend.h
index d73d6ccc6..3752ff0f5 100644
--- a/app/render/backend/audiorenderbackend.h
+++ b/app/render/backend/audiorenderbackend.h
@@ -42,8 +42,6 @@ protected:
   virtual bool CanRender() override;
 
 private:
-  void ValidateRanges();
-
   AudioRenderingParams params_;
 
 };
diff --git a/app/render/backend/opengl/openglbackend.cpp b/app/render/backend/opengl/openglbackend.cpp
index 99d393919..5ad01648f 100644
--- a/app/render/backend/opengl/openglbackend.cpp
+++ b/app/render/backend/opengl/openglbackend.cpp
@@ -141,7 +141,7 @@ void OpenGLBackend::DecompileInternal()
   shader_cache_.Clear();
 }
 
-void OpenGLBackend::EmitCachedFrameReady(const QList<rational> &times, const QVariant &value)
+void OpenGLBackend::EmitCachedFrameReady(const QList<rational> &times, const QVariant &value, qint64 job_time)
 {
   OpenGLTextureCache::ReferencePtr ref = value.value<OpenGLTextureCache::ReferencePtr>();
   OpenGLTexturePtr tex;
@@ -153,7 +153,7 @@ void OpenGLBackend::EmitCachedFrameReady(const QList<rational> &times, const QVa
   }
 
   foreach (const rational& t, times) {
-    emit CachedFrameReady(t, QVariant::fromValue(tex));
+    emit CachedFrameReady(t, QVariant::fromValue(tex), job_time);
   }
 }
 
diff --git a/app/render/backend/opengl/openglbackend.h b/app/render/backend/opengl/openglbackend.h
index 506e5c81a..ac6f970fe 100644
--- a/app/render/backend/opengl/openglbackend.h
+++ b/app/render/backend/opengl/openglbackend.h
@@ -28,7 +28,7 @@ protected:
 
   virtual void DecompileInternal() override;
 
-  virtual void EmitCachedFrameReady(const QList<rational> &times, const QVariant& value) override;
+  virtual void EmitCachedFrameReady(const QList<rational> &times, const QVariant& value, qint64 job_time) override;
 
 private:
   OpenGLTexturePtr CopyTexture(OpenGLTexturePtr input);
diff --git a/app/render/backend/renderbackend.h b/app/render/backend/renderbackend.h
index 247c82e31..77895a157 100644
--- a/app/render/backend/renderbackend.h
+++ b/app/render/backend/renderbackend.h
@@ -90,7 +90,7 @@ protected:
   bool WorkerIsBusy(RenderWorker* worker) const;
   void SetWorkerBusyState(RenderWorker* worker, bool busy);
 
-  QList<TimeRange> cache_queue_;
+  TimeRangeList cache_queue_;
 
   QVector<RenderWorker*> processors_;
 
diff --git a/app/render/backend/videorenderbackend.cpp b/app/render/backend/videorenderbackend.cpp
index 7ba579030..140d85d8a 100644
--- a/app/render/backend/videorenderbackend.cpp
+++ b/app/render/backend/videorenderbackend.cpp
@@ -159,6 +159,13 @@ void VideoRenderBackend::SetExportMode(bool enabled)
   export_mode_ = enabled;
 }
 
+bool VideoRenderBackend::IsRendered(const rational &time) const
+{
+  TimeRange range(time, time);
+
+  return !TimeIsQueued(range) && !render_job_info_.contains(range);
+}
+
 bool VideoRenderBackend::GenerateCacheIDInternal(QCryptographicHash& hash)
 {
   if (!params_.is_valid()) {
@@ -250,7 +257,7 @@ bool VideoRenderBackend::CanRender()
 void VideoRenderBackend::ThreadCompletedFrame(NodeDependency path, qint64 job_time, QByteArray hash, QVariant value)
 {
   if (last_time_requested_ == path.in() || frame_cache_.TimeToHash(last_time_requested_) == hash) {
-    EmitCachedFrameReady({last_time_requested_}, value);
+    EmitCachedFrameReady({last_time_requested_}, value, job_time);
   }
 }
 
@@ -258,7 +265,13 @@ void VideoRenderBackend::ThreadCompletedDownload(NodeDependency dep, qint64 job_
 {
   SetWorkerBusyState(static_cast<RenderWorker*>(sender()), false);
 
-  SetFrameHash(dep, hash, job_time);
+  if (SetFrameHash(dep, hash, job_time)) {
+    QList<rational> hashes_with_time = frame_cache()->FramesWithHash(hash);
+
+    foreach (const rational& t, hashes_with_time) {
+      emit CachedTimeReady(t, job_time);
+    }
+  }
 
   // Queue up a new frame for this worker
   CacheNext();
@@ -269,9 +282,8 @@ void VideoRenderBackend::ThreadSkippedFrame(NodeDependency dep, qint64 job_time,
   SetWorkerBusyState(static_cast<RenderWorker*>(sender()), false);
 
   if (SetFrameHash(dep, hash, job_time)
-      && last_time_requested_ == dep.in()
       && frame_cache_.HasHash(hash)) {
-    emit CachedTimeReady(dep.in());
+    emit CachedTimeReady(dep.in(), job_time);
   }
 
   // Queue up a new frame for this worker
@@ -282,9 +294,8 @@ void VideoRenderBackend::ThreadHashAlreadyExists(NodeDependency dep, qint64 job_
 {
   SetWorkerBusyState(static_cast<RenderWorker*>(sender()), false);
 
-  if (SetFrameHash(dep, hash, job_time)
-      && dep.in() == last_time_requested_) {
-    emit CachedTimeReady(dep.in());
+  if (SetFrameHash(dep, hash, job_time)) {
+    emit CachedTimeReady(dep.in(), job_time);
   }
 
   // Queue up a new frame for this worker
diff --git a/app/render/backend/videorenderbackend.h b/app/render/backend/videorenderbackend.h
index 28515c201..e60cd388b 100644
--- a/app/render/backend/videorenderbackend.h
+++ b/app/render/backend/videorenderbackend.h
@@ -55,6 +55,8 @@ public:
 
   void SetExportMode(bool enabled);
 
+  bool IsRendered(const rational& time) const;
+
 public slots:
   virtual void InvalidateCache(const rational &start_range, const rational &end_range) override;
 
@@ -97,13 +99,13 @@ protected:
 
   virtual void ConnectWorkerToThis(RenderWorker* processor) override;
 
-  virtual void EmitCachedFrameReady(const QList<rational> &times, const QVariant& value) = 0;
+  virtual void EmitCachedFrameReady(const QList<rational> &times, const QVariant& value, qint64 job_time) = 0;
 
   bool export_mode_;
 
 signals:
-  void CachedFrameReady(const rational& time, QVariant value);
-  void CachedTimeReady(const rational& time);
+  void CachedFrameReady(const rational& time, QVariant value, qint64 job_time);
+  void CachedTimeReady(const rational& time, qint64 job_time);
 
 private:
   bool TimeIsQueued(const TimeRange &time) const;
diff --git a/app/render/backend/videorenderframecache.cpp b/app/render/backend/videorenderframecache.cpp
index 54069f69f..fa6434c11 100644
--- a/app/render/backend/videorenderframecache.cpp
+++ b/app/render/backend/videorenderframecache.cpp
@@ -81,6 +81,21 @@ void VideoRenderFrameCache::RemoveHashFromCurrentlyCaching(const QByteArray &has
   currently_caching_lock_.unlock();
 }
 
+QList<rational> VideoRenderFrameCache::FramesWithHash(const QByteArray &hash)
+{
+  QList<rational> times;
+
+  QMap<rational, QByteArray>::const_iterator iterator;
+
+  for (iterator=time_hash_map_.begin();iterator!=time_hash_map_.end();iterator++) {
+    if (iterator.value() == hash) {
+      times.append(iterator.key());
+    }
+  }
+
+  return times;
+}
+
 QString VideoRenderFrameCache::CachePathName(const QByteArray &hash) const
 {
   QDir this_cache_dir = QDir(GetMediaCacheLocation()).filePath(cache_id_);
diff --git a/app/render/backend/videorenderframecache.h b/app/render/backend/videorenderframecache.h
index 008075588..f4c9e204d 100644
--- a/app/render/backend/videorenderframecache.h
+++ b/app/render/backend/videorenderframecache.h
@@ -41,6 +41,8 @@ public:
 
   void RemoveHashFromCurrentlyCaching(const QByteArray& hash);
 
+  QList<rational> FramesWithHash(const QByteArray& hash);
+
 private:
   QMap<rational, QByteArray> time_hash_map_;
 
diff --git a/app/widget/timelinewidget/timelinescaledobject.h b/app/widget/timelinewidget/timelinescaledobject.h
index 9c8296f69..c88d2bada 100644
--- a/app/widget/timelinewidget/timelinescaledobject.h
+++ b/app/widget/timelinewidget/timelinescaledobject.h
@@ -22,10 +22,10 @@ protected:
   double scale_;
 
 private:
-
   rational timebase_;
 
   double timebase_dbl_;
+
 };
 
 #endif // TIMELINESCALEDOBJECT_H
diff --git a/app/widget/timelinewidget/timelinewidget.cpp b/app/widget/timelinewidget/timelinewidget.cpp
index 176ef7e47..2ea8d9f15 100644
--- a/app/widget/timelinewidget/timelinewidget.cpp
+++ b/app/widget/timelinewidget/timelinewidget.cpp
@@ -32,7 +32,7 @@ TimelineWidget::TimelineWidget(QWidget *parent) :
   connect(timecode_label_, SIGNAL(ValueChanged(int64_t)), this, SLOT(UpdateInternalTime(const int64_t&)));
   ruler_and_time_layout->addWidget(timecode_label_);
 
-  ruler_ = new TimeRuler(true);
+  ruler_ = new TimeRuler(true, true);
   connect(ruler_, SIGNAL(TimeChanged(const int64_t&)), this, SIGNAL(TimeChanged(const int64_t&)));
   connect(ruler_, SIGNAL(TimeChanged(const int64_t&)), this, SLOT(UpdateInternalTime(const int64_t&)));
   ruler_and_time_layout->addWidget(ruler_);
@@ -60,7 +60,6 @@ TimelineWidget::TimelineWidget(QWidget *parent) :
   tools_.replace(::Tool::kRazor, std::make_shared<RazorTool>(this));
   tools_.replace(::Tool::kSlip, std::make_shared<SlipTool>(this));
   tools_.replace(::Tool::kSlide, std::make_shared<SlideTool>(this));
-//  tools_.replace(::Tool::kHand, std::make_shared<HandTool>(this));
   tools_.replace(::Tool::kZoom, std::make_shared<ZoomTool>(this));
   tools_.replace(::Tool::kTransition, std::make_shared<TransitionTool>(this));
   //tools_.replace(::Tool::kRecord, new PointerTool(this));  FIXME: Implement
diff --git a/app/widget/timelinewidget/view/timelineviewbase.cpp b/app/widget/timelinewidget/view/timelineviewbase.cpp
index 84452b5a5..6e31f3a26 100644
--- a/app/widget/timelinewidget/view/timelineviewbase.cpp
+++ b/app/widget/timelinewidget/view/timelineviewbase.cpp
@@ -14,6 +14,7 @@ TimelineViewBase::TimelineViewBase(QWidget *parent) :
   playhead_(0),
   playhead_scene_left_(-1),
   playhead_scene_right_(-1),
+  dragging_hand_(false),
   limit_y_axis_(false)
 {
   setScene(&scene_);
diff --git a/app/widget/timeruler/timeruler.cpp b/app/widget/timeruler/timeruler.cpp
index d23315025..38f05be0e 100644
--- a/app/widget/timeruler/timeruler.cpp
+++ b/app/widget/timeruler/timeruler.cpp
@@ -30,13 +30,14 @@
 #include "config/config.h"
 #include "core.h"
 
-TimeRuler::TimeRuler(bool text_visible, QWidget* parent) :
+TimeRuler::TimeRuler(bool text_visible, bool cache_status_visible, QWidget* parent) :
   QWidget(parent),
   scroll_(0),
+  text_visible_(text_visible),
   centered_text_(true),
   scale_(1.0),
   time_(0),
-  snapping_(false)
+  show_cache_status_(cache_status_visible)
 {
   QFontMetrics fm = fontMetrics();
 
@@ -44,6 +45,7 @@ TimeRuler::TimeRuler(bool text_visible, QWidget* parent) :
 
   // Text height is used to calculate widget height
   text_height_ = fm.height();
+  cache_status_height_ = text_height_ / 4;
 
   // Get the "minimum" space allowed between two line markers on the ruler (in screen pixels)
   // Mediocre but reliable way of scaling UI objects by font/DPI size
@@ -53,22 +55,7 @@ TimeRuler::TimeRuler(bool text_visible, QWidget* parent) :
   playhead_width_ = minimum_gap_between_lines_;
 
   // Text visibility affects height, so we set that here
-  SetTextVisible(text_visible);
-}
-
-void TimeRuler::SetTextVisible(bool e)
-{
-  text_visible_ = e;
-
-  // Text visibility affects height, if text is visible the widget doubles in height with the top half for text and
-  // the bottom half for ruler markings
-  if (text_visible_) {
-    setMinimumHeight(text_height_ * 2);
-  } else {
-    setMinimumHeight(text_height_);
-  }
-
-  update();
+  UpdateHeight();
 }
 
 const double &TimeRuler::scale()
@@ -94,16 +81,20 @@ void TimeRuler::SetTimebase(const rational &r)
   update();
 }
 
-void TimeRuler::SetSnapping(bool snapping)
-{
-  snapping_ = snapping;
-}
-
 const int64_t &TimeRuler::GetTime()
 {
   return time_;
 }
 
+void TimeRuler::SetCacheStatusLength(const rational &length)
+{
+  cache_length_ = length;
+
+  dirty_cache_ranges_.RemoveTimeRange(TimeRange(length, RATIONAL_MAX));
+
+  update();
+}
+
 void TimeRuler::SetTime(const int64_t &r)
 {
   time_ = r;
@@ -118,6 +109,20 @@ void TimeRuler::SetScroll(int s)
   update();
 }
 
+void TimeRuler::CacheInvalidatedRange(const rational& in, const rational& out)
+{
+  dirty_cache_ranges_.InsertTimeRange(TimeRange(in, out));
+
+  update();
+}
+
+void TimeRuler::CacheTimeReady(const rational &time)
+{
+  dirty_cache_ranges_.RemoveTimeRange(TimeRange(time, time + timebase_));
+
+  update();
+}
+
 void TimeRuler::paintEvent(QPaintEvent *)
 {
   // Nothing to paint if the timebase is invalid
@@ -198,11 +203,16 @@ void TimeRuler::paintEvent(QPaintEvent *)
 
   // Calculate line dimensions
   QFontMetrics fm = p.fontMetrics();
+  int line_bottom = height();
+
+  if (show_cache_status_) {
+    line_bottom -= cache_status_height_;
+  }
+
   int long_height = fm.height();
   int short_height = long_height/2;
-  int long_y = height() - long_height;
-  int short_y = height() - short_height;
-  int line_bottom = height();
+  int long_y = line_bottom - long_height;
+  int short_y = line_bottom - short_height;
 
   // Draw long lines
   int last_long_unit = -1;
@@ -267,12 +277,34 @@ void TimeRuler::paintEvent(QPaintEvent *)
     }
   }
 
+  // If cache status is enabled
+  if (show_cache_status_) {
+    int cache_screen_length = qMin(TimeToScreen(cache_length_), width());
+
+    if (cache_screen_length > 0) {
+      int cache_y = height() - cache_status_height_;
+
+      p.fillRect(0, cache_y, cache_screen_length , cache_status_height_, Qt::green);
+
+      foreach (const TimeRange& range, dirty_cache_ranges_) {
+        int range_left = TimeToScreen(range.in());
+        int range_right = TimeToScreen(range.out());
+
+        if (range_left >= width() || range_right < 0) {
+          continue;
+        }
+
+        p.fillRect(qMax(0, range_left), cache_y, qMin(width(), range_right) - range_left, cache_status_height_, Qt::red);
+      }
+    }
+  }
+
   // Draw the playhead if it's on screen at the moment
-  int playhead_pos = qFloor(static_cast<double>(time_) * scale_ * timebase_dbl_) - scroll_;
+  int playhead_pos = UnitToScreen(time_);
   if (playhead_pos + playhead_width_ >= 0 && playhead_pos - playhead_width_ < width()) {
     p.setPen(Qt::NoPen);
     p.setBrush(style_.PlayheadColor());
-    DrawPlayhead(&p, playhead_pos, height());
+    DrawPlayhead(&p, playhead_pos, line_bottom);
   }
 }
 
@@ -317,6 +349,16 @@ int64_t TimeRuler::ScreenToUnit(int screen)
   return qFloor(ScreenToUnitFloat(screen));
 }
 
+int TimeRuler::UnitToScreen(int64_t unit)
+{
+  return qFloor(static_cast<double>(unit) * scale_ * timebase_dbl_) - scroll_;
+}
+
+int TimeRuler::TimeToScreen(const rational &time)
+{
+  return qFloor(time.toDouble() * scale_) - scroll_;
+}
+
 void TimeRuler::SeekToScreenPoint(int screen)
 {
   int64_t timestamp = qMax(0, qRound(ScreenToUnitFloat(screen)));
@@ -325,3 +367,18 @@ void TimeRuler::SeekToScreenPoint(int screen)
 
   emit TimeChanged(timestamp);
 }
+
+void TimeRuler::UpdateHeight()
+{
+  int height = text_height_;
+
+  if (text_visible_) {
+    height += text_height_;
+  }
+
+  if (show_cache_status_) {
+    height += cache_status_height_;
+  }
+
+  setFixedHeight(height);
+}
diff --git a/app/widget/timeruler/timeruler.h b/app/widget/timeruler/timeruler.h
index a0a372dae..396913974 100644
--- a/app/widget/timeruler/timeruler.h
+++ b/app/widget/timeruler/timeruler.h
@@ -25,15 +25,14 @@
 #include <QWidget>
 
 #include "common/rational.h"
+#include "common/timerange.h"
 #include "widget/timelinewidget/view/timelineplayhead.h"
 
 class TimeRuler : public QWidget
 {
   Q_OBJECT
 public:
-  TimeRuler(bool text_visible = true, QWidget* parent = nullptr);
-
-  void SetTextVisible(bool e);
+  TimeRuler(bool text_visible = true, bool cache_status_visible = false, QWidget* parent = nullptr);
 
   const double& scale();
   void SetScale(const double& d);
@@ -42,8 +41,6 @@ public:
 
   void SetCenteredText(bool c);
 
-  void SetSnapping(bool snapping);
-
   const int64_t& GetTime();
 
 public slots:
@@ -51,6 +48,12 @@ public slots:
 
   void SetScroll(int s);
 
+  void CacheInvalidatedRange(const rational& in, const rational& out);
+
+  void CacheTimeReady(const rational& time);
+
+  void SetCacheStatusLength(const rational& length);
+
 protected:
   virtual void paintEvent(QPaintEvent* e) override;
 
@@ -64,14 +67,7 @@ signals:
   void TimeChanged(int64_t);
 
 private:
-  enum Component {
-    kNone,
-    kDay,
-    kHour,
-    kMinute,
-    kSecond,
-    kFrame
-  };
+  void UpdateHeight();
 
   void DrawPlayhead(QPainter* p, int x, int y);
 
@@ -79,10 +75,16 @@ private:
 
   int64_t ScreenToUnit(int screen);
 
+  int UnitToScreen(int64_t unit);
+
+  int TimeToScreen(const rational& time);
+
   void SeekToScreenPoint(int screen);
 
   int text_height_;
 
+  int cache_status_height_;
+
   int minimum_gap_between_lines_;
 
   int playhead_width_;
@@ -105,7 +107,11 @@ private:
 
   TimelinePlayhead style_;
 
-  bool snapping_;
+  bool show_cache_status_;
+
+  rational cache_length_;
+
+  TimeRangeList dirty_cache_ranges_;
 
 };
 
diff --git a/app/widget/viewer/viewer.cpp b/app/widget/viewer/viewer.cpp
index 3e2827f46..9683d9601 100644
--- a/app/widget/viewer/viewer.cpp
+++ b/app/widget/viewer/viewer.cpp
@@ -49,7 +49,7 @@ ViewerWidget::ViewerWidget(QWidget *parent) :
   sizer_->SetWidget(gl_widget_);
 
   // Create time ruler
-  ruler_ = new TimeRuler(false);
+  ruler_ = new TimeRuler(false, true);
   layout->addWidget(ruler_);
   connect(ruler_, SIGNAL(TimeChanged(int64_t)), this, SLOT(RulerTimeChange(int64_t)));
 
@@ -79,8 +79,9 @@ ViewerWidget::ViewerWidget(QWidget *parent) :
 
   // Start background renderers
   video_renderer_ = new OpenGLBackend(this);
-  connect(video_renderer_, SIGNAL(CachedFrameReady(const rational&, QVariant)), this, SLOT(RendererCachedFrame(const rational&, QVariant)));
-  connect(video_renderer_, SIGNAL(CachedTimeReady(const rational&)), this, SLOT(RendererCachedTime(const rational&)));
+  connect(video_renderer_, &VideoRenderBackend::CachedFrameReady, this, &ViewerWidget::RendererCachedFrame);
+  connect(video_renderer_, &VideoRenderBackend::CachedTimeReady, this, &ViewerWidget::RendererCachedTime);
+  connect(video_renderer_, &VideoRenderBackend::CachedTimeReady, ruler_, &TimeRuler::CacheTimeReady);
   audio_renderer_ = new AudioBackend(this);
 }
 
@@ -138,9 +139,11 @@ void ViewerWidget::ConnectViewerNode(ViewerOutput *node, ColorManager* color_man
   if (viewer_node_ != nullptr) {
     SetTimebase(0);
 
-    disconnect(viewer_node_, SIGNAL(TimebaseChanged(const rational&)), this, SLOT(SetTimebase(const rational&)));
-    disconnect(viewer_node_, SIGNAL(SizeChanged(int, int)), this, SLOT(SizeChangedSlot(int, int)));
-    disconnect(viewer_node_, SIGNAL(LengthChanged(const rational&)), this, SLOT(LengthChangedSlot(const rational&)));
+    disconnect(viewer_node_, &ViewerOutput::TimebaseChanged, this, &ViewerWidget::SetTimebase);
+    disconnect(viewer_node_, &ViewerOutput::SizeChanged, this, &ViewerWidget::SizeChangedSlot);
+    disconnect(viewer_node_, &ViewerOutput::LengthChanged, this, &ViewerWidget::LengthChangedSlot);
+    disconnect(viewer_node_, &ViewerOutput::LengthChanged, ruler_, &TimeRuler::SetCacheStatusLength);
+    disconnect(viewer_node_, &ViewerOutput::VideoChangedBetween, ruler_, &TimeRuler::CacheInvalidatedRange);
 
     // Effectively disables the viewer and clears the state
     SizeChangedSlot(0, 0);
@@ -159,9 +162,11 @@ void ViewerWidget::ConnectViewerNode(ViewerOutput *node, ColorManager* color_man
   if (viewer_node_ != nullptr) {
     SetTimebase(viewer_node_->video_params().time_base());
 
-    connect(viewer_node_, SIGNAL(TimebaseChanged(const rational&)), this, SLOT(SetTimebase(const rational&)));
-    connect(viewer_node_, SIGNAL(SizeChanged(int, int)), this, SLOT(SizeChangedSlot(int, int)));
-    connect(viewer_node_, SIGNAL(LengthChanged(const rational&)), this, SLOT(LengthChangedSlot(const rational&)));
+    connect(viewer_node_, &ViewerOutput::TimebaseChanged, this, &ViewerWidget::SetTimebase);
+    connect(viewer_node_, &ViewerOutput::SizeChanged, this, &ViewerWidget::SizeChangedSlot);
+    connect(viewer_node_, &ViewerOutput::LengthChanged, this, &ViewerWidget::LengthChangedSlot);
+    connect(viewer_node_, &ViewerOutput::LengthChanged, ruler_, &TimeRuler::SetCacheStatusLength);
+    connect(viewer_node_, &ViewerOutput::VideoChangedBetween, ruler_, &TimeRuler::CacheInvalidatedRange);
 
     SizeChangedSlot(viewer_node_->video_params().width(), viewer_node_->video_params().height());
     LengthChangedSlot(viewer_node_->Length());
@@ -407,16 +412,18 @@ void ViewerWidget::PlaybackTimerUpdate()
   SetTime(current_time);
 }
 
-void ViewerWidget::RendererCachedFrame(const rational &time, QVariant value)
+void ViewerWidget::RendererCachedFrame(const rational &time, QVariant value, qint64 job_time)
 {
   if (GetTime() == time) {
     SetTexture(value.value<OpenGLTexturePtr>());
+
+    frame_cache_job_time_ = job_time;
   }
 }
 
-void ViewerWidget::RendererCachedTime(const rational &time)
+void ViewerWidget::RendererCachedTime(const rational &time, qint64 job_time)
 {
-  if (GetTime() == time) {
+  if (GetTime() == time && job_time > frame_cache_job_time_) {
     UpdateTextureFromNode(GetTime());
   }
 }
diff --git a/app/widget/viewer/viewer.h b/app/widget/viewer/viewer.h
index 8c82e4be8..36bd04ec9 100644
--- a/app/widget/viewer/viewer.h
+++ b/app/widget/viewer/viewer.h
@@ -171,13 +171,15 @@ private:
 
   int playback_speed_;
 
+  qint64 frame_cache_job_time_;
+
 private slots:
   void RulerTimeChange(int64_t);
 
   void PlaybackTimerUpdate();
 
-  void RendererCachedFrame(const rational& time, QVariant value);
-  void RendererCachedTime(const rational& time);
+  void RendererCachedFrame(const rational& time, QVariant value, qint64 job_time);
+  void RendererCachedTime(const rational& time, qint64 job_time);
 
   void SizeChangedSlot(int width, int height);