diff --git a/app/audio/audiovisualwaveform.cpp b/app/audio/audiovisualwaveform.cpp
index c02588cc6..a58a1cd11 100644
--- a/app/audio/audiovisualwaveform.cpp
+++ b/app/audio/audiovisualwaveform.cpp
@@ -28,69 +28,27 @@ OLIVE_NAMESPACE_ENTER
 
 const int AudioVisualWaveform::kSumSampleRate = 200;
 
+void AudioVisualWaveform::AddSamples(SampleBufferPtr samples, int sample_rate)
+{
+  if (!channels_) {
+    qWarning() << "Failed to write samples - channel count is zero";
+  }
+
+  overwrite_samples_internal(samples, sample_rate, 0);
+}
+
 void AudioVisualWaveform::AddSum(const float *samples, int nb_samples, int nb_channels)
 {
   data_.append(SumSamples(samples, nb_samples, nb_channels));
 }
 
-/*
-void AudioVisualWaveform::AddSamples(SampleBufferPtr samples)
-{
-  if (!params_.is_valid()) {
-
-  }
-
-  int chunk_size = (audio_params_.sample_rate() / waveform_params.sample_rate());
-
-  qint64 start_offset = sizeof(SampleSummer::Info) + waveform_params.time_to_bytes(range_for_block.in() - b->in());
-  qint64 length_offset = waveform_params.time_to_bytes(range_for_block.length());
-  qint64 end_offset = start_offset + length_offset;
-
-  if (wave_file.size() < end_offset) {
-    wave_file.resize(end_offset);
-  }
-
-  wave_file.seek(start_offset);
-
-  for (int i=0;i<samples->sample_count();i+=chunk_size) {
-    QVector<Sample> summary = SumSamples(samples,
-                                         i,
-                                         qMin(chunk_size, samples->sample_count_per_channel() - i));
-
-    wave_file.write(reinterpret_cast<const char*>(summary.constData()),
-                    summary.size() * sizeof(SampleSummer::Sum));
-  }
-}
-*/
-
 void AudioVisualWaveform::OverwriteSamples(SampleBufferPtr samples, int sample_rate, const rational &start)
 {
   if (!channels_) {
     qWarning() << "Failed to write samples - channel count is zero";
   }
 
-  int start_index = time_to_samples(start);
-  int samples_length = time_to_samples(static_cast<double>(samples->sample_count()) / static_cast<double>(sample_rate));
-
-  int end_index = start_index + samples_length;
-  if (data_.size() < end_index) {
-    data_.resize(end_index);
-  }
-
-  int chunk_size = sample_rate / kSumSampleRate;
-
-  for (int i=0; i<samples_length; i++) {
-
-    int src_index = (i * chunk_size) / channels_;
-
-    QVector<SamplePerChannel> summary = SumSamples(samples,
-                                                   src_index,
-                                                   qMin(chunk_size, samples->sample_count() - src_index));
-
-    memcpy(&data_.data()[i + start_index],
-        summary.constData(),
-        summary.size() * sizeof(SamplePerChannel));
-  }
+  overwrite_samples_internal(samples, sample_rate, time_to_samples(start));
 }
 
 void AudioVisualWaveform::OverwriteSums(const AudioVisualWaveform &sums, const rational &start)
@@ -150,10 +108,7 @@ void AudioVisualWaveform::PrependSilence(const rational &time)
   }
 
   // Fill remainder with silence
-  for (int i=0;i<added_samples;i++) {
-    data_[i].max = 0;
-    data_[i].min = 0;
-  }
+  memset(data_.data(), 0, added_samples * sizeof(SamplePerChannel));
 }
 
 void AudioVisualWaveform::AppendSilence(const rational &time)
@@ -165,10 +120,7 @@ void AudioVisualWaveform::AppendSilence(const rational &time)
   data_.resize(old_size + added_samples);
 
   // Fill remainder with silence
-  for (int i=old_size;i<data_.size();i++) {
-    data_[i].max = 0;
-    data_[i].min = 0;
-  }
+  memset(&data_[old_size], 0, (data_.size() - old_size) * sizeof(SamplePerChannel));
 }
 
 QVector<AudioVisualWaveform::SamplePerChannel> AudioVisualWaveform::SumSamples(const float *samples, int nb_samples, int nb_channels)
@@ -245,9 +197,11 @@ void AudioVisualWaveform::DrawSample(QPainter *painter, const QVector<SamplePerC
   }
 }
 
-void AudioVisualWaveform::DrawWaveform(QPainter *painter, const QRect& rect, const double& scale, const AudioVisualWaveform &samples)
+void AudioVisualWaveform::DrawWaveform(QPainter *painter, const QRect& rect, const double& scale, const AudioVisualWaveform &samples, const rational& start_time)
 {
-  int sample_index, next_sample_index = 0;
+  int start_sample_index = samples.time_to_samples(start_time);
+  int next_sample_index = start_sample_index;
+  int sample_index;
 
   QVector<SamplePerChannel> summary;
   int summary_index = -1;
@@ -258,8 +212,6 @@ void AudioVisualWaveform::DrawWaveform(QPainter *painter, const QRect& rect, con
   int start = qMax(rect.x(), -top_left.x());
   int end = qMin(rect.right(), -top_left.x() + viewport.width());
 
-  QVector<QLine> lines;
-
   for (int i=start;i<end;i++) {
     sample_index = next_sample_index;
 
@@ -268,7 +220,7 @@ void AudioVisualWaveform::DrawWaveform(QPainter *painter, const QRect& rect, con
     }
 
     next_sample_index = qMin(samples.nb_samples(),
-                             qFloor(static_cast<double>(kSumSampleRate) * static_cast<double>(i - rect.x() + 1) / scale) * samples.channel_count());
+                             start_sample_index + qFloor(static_cast<double>(kSumSampleRate) * static_cast<double>(i - rect.x() + 1) / scale) * samples.channel_count());
 
     if (summary_index != sample_index) {
       summary = AudioVisualWaveform::ReSumSamples(&samples.data_.at(sample_index),
@@ -279,8 +231,31 @@ void AudioVisualWaveform::DrawWaveform(QPainter *painter, const QRect& rect, con
 
     DrawSample(painter, summary, i, rect.y(), rect.height());
   }
+}
 
-  painter->drawLines(lines);
+void AudioVisualWaveform::overwrite_samples_internal(SampleBufferPtr samples, int sample_rate, int start_index)
+{
+  int samples_length = time_to_samples(static_cast<double>(samples->sample_count()) / static_cast<double>(sample_rate));
+
+  int end_index = start_index + samples_length;
+  if (data_.size() < end_index) {
+    data_.resize(end_index);
+  }
+
+  int chunk_size = sample_rate / kSumSampleRate;
+
+  for (int i=0; i<samples_length; i++) {
+
+    int src_index = (i * chunk_size) / channels_;
+
+    QVector<SamplePerChannel> summary = SumSamples(samples,
+                                                   src_index,
+                                                   qMin(chunk_size, samples->sample_count() - src_index));
+
+    memcpy(&data_.data()[i + start_index],
+        summary.constData(),
+        summary.size() * sizeof(SamplePerChannel));
+  }
 }
 
 int AudioVisualWaveform::time_to_samples(const rational &time) const
diff --git a/app/audio/audiovisualwaveform.h b/app/audio/audiovisualwaveform.h
index c13ada097..434461860 100644
--- a/app/audio/audiovisualwaveform.h
+++ b/app/audio/audiovisualwaveform.h
@@ -66,6 +66,7 @@ public:
     return data_.constData();
   }
 
+  void AddSamples(SampleBufferPtr samples, int sample_rate);
   void AddSum(const float* samples, int nb_samples, int nb_channels);
 
   void OverwriteSamples(SampleBufferPtr samples, int sample_rate, const rational& start);
@@ -89,7 +90,7 @@ public:
 
   static void DrawSample(QPainter* painter, const QVector<SamplePerChannel> &sample, int x, int y, int height);
 
-  static void DrawWaveform(QPainter* painter, const QRect &rect, const double &scale, const AudioVisualWaveform& samples);
+  static void DrawWaveform(QPainter* painter, const QRect &rect, const double &scale, const AudioVisualWaveform& samples, const rational &start_time);
 
 private:
   template <typename T>
@@ -98,6 +99,8 @@ private:
   template <typename T>
   static void ClampMinMax(SamplePerChannel &sum, T value);
 
+  void overwrite_samples_internal(SampleBufferPtr samples, int sample_rate, int start_index);
+
   int time_to_samples(const rational& time) const;
   int time_to_samples(const double& time) const;
 
@@ -109,4 +112,6 @@ private:
 
 OLIVE_NAMESPACE_EXIT
 
+Q_DECLARE_METATYPE(OLIVE_NAMESPACE::AudioVisualWaveform)
+
 #endif // SUMSAMPLES_H
diff --git a/app/core.cpp b/app/core.cpp
index ba838dbdc..58295d300 100644
--- a/app/core.cpp
+++ b/app/core.cpp
@@ -552,6 +552,7 @@ void Core::DeclareTypesForQt()
   qRegisterMetaType<OLIVE_NAMESPACE::TimeRange>();
   qRegisterMetaType<Color>();
   qRegisterMetaType<OLIVE_NAMESPACE::ProjectPtr>();
+  qRegisterMetaType<OLIVE_NAMESPACE::AudioVisualWaveform>();
 }
 
 void Core::StartGUI(bool full_screen)
diff --git a/app/node/block/block.h b/app/node/block/block.h
index 1d881fa17..6568ca543 100644
--- a/app/node/block/block.h
+++ b/app/node/block/block.h
@@ -28,13 +28,6 @@ OLIVE_NAMESPACE_ENTER
 
 /**
  * @brief A Node that represents a block of time, also displayable on a Timeline
- *
- * This is an abstract function. Since different types of Block will provide their lengths in different ways, it's
- * necessary to subclass and override the length() function for a Block to be usable.
- *
- * When overriding Node::copy(), the derivative class should also call Block::CopyParameters() on the new Block instance
- * which will copy the block's name, length, and media in point. It does not copy any node-specific parameters like any
- * input values or connections as per standard with Node::copy().
  */
 class Block : public Node
 {
diff --git a/app/node/block/clip/clip.cpp b/app/node/block/clip/clip.cpp
index 604ce0204..851f8b9f8 100644
--- a/app/node/block/clip/clip.cpp
+++ b/app/node/block/clip/clip.cpp
@@ -59,26 +59,6 @@ NodeInput *ClipBlock::texture_input() const
   return texture_input_;
 }
 
-void ClipBlock::LengthChangedEvent(const rational &old_length, const rational &new_length, const Timeline::MovementMode &mode)
-{
-  // Positive if made longer, negative if made shorter
-  rational diff = new_length - old_length;
-
-  if (diff < rational()) {
-    if (mode == Timeline::kTrimIn) {
-      waveform().TrimIn(-diff);
-    } else {
-      waveform().TrimOut(-diff);
-    }
-  } else {
-    if (mode == Timeline::kTrimIn) {
-      waveform().PrependSilence(diff);
-    } else {
-      waveform().AppendSilence(diff);
-    }
-  }
-}
-
 void ClipBlock::InvalidateCache(const TimeRange &range, NodeInput *from, NodeInput *source)
 {
   // If signal is from texture input, transform all times from media time to sequence time
diff --git a/app/node/block/clip/clip.h b/app/node/block/clip/clip.h
index 8cecf96f2..00f6e0ba0 100644
--- a/app/node/block/clip/clip.h
+++ b/app/node/block/clip/clip.h
@@ -21,7 +21,6 @@
 #ifndef CLIPBLOCK_H
 #define CLIPBLOCK_H
 
-#include "audio/audiovisualwaveform.h"
 #include "node/block/block.h"
 
 OLIVE_NAMESPACE_ENTER
@@ -57,31 +56,9 @@ public:
 
   virtual void Hash(QCryptographicHash &hash, const rational &time) const override;
 
-  AudioVisualWaveform& waveform()
-  {
-    return waveform_;
-  }
-
-  void set_waveform(const AudioVisualWaveform& wave)
-  {
-    waveform_ = wave;
-
-    emit PreviewUpdated();
-  }
-
-signals:
-  void PreviewUpdated();
-
-protected:
-  virtual void LengthChangedEvent(const rational& old_length,
-                                  const rational& new_length,
-                                  const Timeline::MovementMode& mode) override;
-
 private:
   NodeInput* texture_input_;
 
-  AudioVisualWaveform waveform_;
-
 };
 
 OLIVE_NAMESPACE_EXIT
diff --git a/app/node/output/track/track.cpp b/app/node/output/track/track.cpp
index 28b6ab73d..8d60a5534 100644
--- a/app/node/output/track/track.cpp
+++ b/app/node/output/track/track.cpp
@@ -63,12 +63,7 @@ const Timeline::TrackType& TrackOutput::track_type() const
   return track_type_;
 }
 
-Block::Type TrackOutput::type() const
-{
-  return kClip;
-}
-
-Block *TrackOutput::copy() const
+Node *TrackOutput::copy() const
 {
   return new TrackOutput();
 }
@@ -116,7 +111,7 @@ void TrackOutput::SetTrackHeight(const int &height)
 
 void TrackOutput::Retranslate()
 {
-  Block::Retranslate();
+  Node::Retranslate();
 
   block_input_->set_name(tr("Blocks"));
   muted_input_->set_name(tr("Muted"));
diff --git a/app/node/output/track/track.h b/app/node/output/track/track.h
index a17f82ea9..85c995870 100644
--- a/app/node/output/track/track.h
+++ b/app/node/output/track/track.h
@@ -21,6 +21,7 @@
 #ifndef TRACKOUTPUT_H
 #define TRACKOUTPUT_H
 
+#include "audio/audiovisualwaveform.h"
 #include "node/block/block.h"
 #include "timeline/timelinecommon.h"
 
@@ -29,7 +30,7 @@ OLIVE_NAMESPACE_ENTER
 /**
  * @brief A time traversal Node for sorting through one channel/track of Blocks
  */
-class TrackOutput : public Block
+class TrackOutput : public Node
 {
   Q_OBJECT
 public:
@@ -38,9 +39,7 @@ public:
   const Timeline::TrackType& track_type() const;
   void set_track_type(const Timeline::TrackType& track_type);
 
-  virtual Type type() const override;
-
-  virtual Block* copy() const override;
+  virtual Node* copy() const override;
 
   virtual QString Name() const override;
   virtual QString id() const override;
@@ -195,6 +194,11 @@ public:
 
   void PushLengthChangeSignal();
 
+  AudioVisualWaveform& waveform()
+  {
+    return waveform_;
+  }
+
 public slots:
   void SetTrackName(const QString& name);
 
@@ -233,6 +237,11 @@ signals:
    */
   void IndexChanged(int i);
 
+  /**
+   * @brief Signal emitted when preview (waveform) has changed and UI should be updated
+   */
+  void PreviewChanged();
+
 protected:
 
 private:
@@ -266,6 +275,8 @@ private:
   bool queued_length_change_;
   rational queued_length_;
 
+  AudioVisualWaveform waveform_;
+
 private slots:
   void BlockConnected(NodeEdgePtr edge);
 
diff --git a/app/render/backend/renderbackend.cpp b/app/render/backend/renderbackend.cpp
index bf5153d67..6a214fc5b 100644
--- a/app/render/backend/renderbackend.cpp
+++ b/app/render/backend/renderbackend.cpp
@@ -94,11 +94,6 @@ void RenderBackend::SetViewerNode(ViewerOutput *viewer_node)
   }
 }
 
-void RenderBackend::SetUpdateWithGraph(bool e)
-{
-  update_with_graph_ = e;
-}
-
 void RenderBackend::ClearVideoQueue()
 {
   foreach (RenderTicketPtr t, render_queue_) {
@@ -275,6 +270,7 @@ void RenderBackend::RunNextJob()
       RenderWorker* worker = CreateNewWorker();
 
       connect(worker, &RenderWorker::FinishedJob, this, &RenderBackend::WorkerFinished);
+      connect(worker, &RenderWorker::WaveformGenerated, this, &RenderBackend::WorkerGeneratedWaveform);
 
       workers_.replace(i, {worker, false});
     }
@@ -292,6 +288,7 @@ void RenderBackend::RunNextJob()
       worker->SetVideoParams(video_params_);
       worker->SetAudioParams(audio_params_);
       worker->SetVideoDownloadMatrix(video_download_matrix_);
+      worker->SetGeneratePreviews(generate_previews_);
       worker->SetCopyMap(&copy_map_);
 
       RenderTicketPtr ticket = render_queue_.front();
@@ -354,6 +351,34 @@ void RenderBackend::WorkerFinished()
   }
 }
 
+void RenderBackend::WorkerGeneratedWaveform(const TrackOutput *copied_track, const AudioVisualWaveform& samples, const rational &r)
+{
+  TrackOutput* track = nullptr;
+
+  /*
+  if (!viewer_node_->audio_playback_cache()->JobIsCurrent(r)) {
+    return;
+  }
+  */
+
+  QHash<Node*, Node*>::const_iterator i;
+  for (i=copy_map_.constBegin(); i!=copy_map_.constEnd(); i++) {
+    if (i.value() == copied_track) {
+      track = static_cast<TrackOutput*>(i.key());
+      break;
+    }
+  }
+
+  if (track) {
+    track->waveform().set_channel_count(audio_params_.channel_count());
+    track->waveform().OverwriteSums(samples, r);
+    qDebug() << "Preview changed";
+    emit track->PreviewChanged();
+  } else {
+    qDebug() << "Failed to find track";
+  }
+}
+
 void RenderBackend::CopyNodeInputValue(NodeInput *input)
 {
   // Find our copy of this parameter
diff --git a/app/render/backend/renderbackend.h b/app/render/backend/renderbackend.h
index e8b1d043d..6812b6db2 100644
--- a/app/render/backend/renderbackend.h
+++ b/app/render/backend/renderbackend.h
@@ -45,7 +45,15 @@ public:
 
   void SetViewerNode(ViewerOutput* viewer_node);
 
-  void SetUpdateWithGraph(bool e);
+  void SetUpdateWithGraph(bool e)
+  {
+    update_with_graph_ = e;
+  }
+
+  void SetGeneratePreviews(bool e)
+  {
+    generate_previews_ = e;
+  }
 
   void ClearVideoQueue();
 
@@ -113,9 +121,13 @@ private:
 
   bool update_with_graph_;
 
+  bool generate_previews_;
+
 private slots:
   void WorkerFinished();
 
+  void WorkerGeneratedWaveform(const OLIVE_NAMESPACE::TrackOutput* copied_track, const OLIVE_NAMESPACE::AudioVisualWaveform& samples, const OLIVE_NAMESPACE::rational& start);
+
 };
 
 OLIVE_NAMESPACE_EXIT
diff --git a/app/render/backend/renderworker.cpp b/app/render/backend/renderworker.cpp
index 5e465af50..a0c3aa762 100644
--- a/app/render/backend/renderworker.cpp
+++ b/app/render/backend/renderworker.cpp
@@ -34,7 +34,8 @@ OLIVE_NAMESPACE_ENTER
 RenderWorker::RenderWorker(RenderBackend* parent) :
   parent_(parent),
   available_(true),
-  audio_mode_is_preview_(false)
+  audio_mode_is_preview_(false),
+  generate_previews_(false)
 {
 }
 
@@ -123,24 +124,17 @@ NodeValueTable RenderWorker::GenerateBlockTable(const TrackOutput *track, const
       // Copy samples into destination buffer
       block_range_buffer->set(samples_from_this_block->const_data(), destination_offset, copy_length);
 
-      if (b->type() == Block::kClip) {
-        // Save waveform to file
-        ClipBlock* src_block = static_cast<ClipBlock*>(copy_map_->key(b));
-
-        AudioVisualWaveform& clip_waveform = src_block->waveform();
-
-        clip_waveform.set_channel_count(audio_params_.channel_count());
-
-        clip_waveform.OverwriteSamples(samples_from_this_block,
-                                       audio_params_.sample_rate(),
-                                       range_for_block.in() - b->in());
-
-        emit static_cast<ClipBlock*>(src_block)->PreviewUpdated();
-      }
-
       NodeValueTable::Merge({merged_table, table});
     }
 
+    if (generate_previews_) {
+      // Generate visual waveform in this background thread
+      AudioVisualWaveform visual_waveform;
+      visual_waveform.set_channel_count(audio_params_.channel_count());
+      visual_waveform.AddSamples(block_range_buffer, audio_params_.sample_rate());
+      emit WaveformGenerated(track, visual_waveform, range.in());
+    }
+
     merged_table.Push(NodeParam::kSamples, QVariant::fromValue(block_range_buffer));
 
     return merged_table;
diff --git a/app/render/backend/renderworker.h b/app/render/backend/renderworker.h
index fc8cf5fc2..8ebc3d8f3 100644
--- a/app/render/backend/renderworker.h
+++ b/app/render/backend/renderworker.h
@@ -73,6 +73,11 @@ public:
     copy_map_ = copy_map;
   }
 
+  void SetGeneratePreviews(bool e)
+  {
+    generate_previews_ = e;
+  }
+
   /**
    * @brief Return a unique ID for the image generated at this time
    *
@@ -127,6 +132,8 @@ signals:
 
   void FinishedJob();
 
+  void WaveformGenerated(const OLIVE_NAMESPACE::TrackOutput* track, const OLIVE_NAMESPACE::AudioVisualWaveform& samples, const OLIVE_NAMESPACE::rational& start);
+
 private:
   NodeValue GetDataFromStream(StreamPtr stream, const TimeRange& input_time);
 
@@ -157,6 +164,8 @@ private:
 
   bool audio_mode_is_preview_;
 
+  bool generate_previews_;
+
   QHash<Node*, Node*>* copy_map_;
 
 };
diff --git a/app/task/cache/cache.cpp b/app/task/cache/cache.cpp
index 4c10bf1cf..ed9df21c6 100644
--- a/app/task/cache/cache.cpp
+++ b/app/task/cache/cache.cpp
@@ -32,6 +32,8 @@ CacheTask::CacheTask(ViewerOutput* viewer, const VideoRenderingParams& vparams,
   in_out_only_(in_out_only)
 {
   SetTitle(tr("Caching \"%1\"").arg(viewer->media_name()));
+
+  backend()->SetGeneratePreviews(true);
 }
 
 bool CacheTask::Run()
diff --git a/app/task/render/render.h b/app/task/render/render.h
index e51b9681a..14f56e138 100644
--- a/app/task/render/render.h
+++ b/app/task/render/render.h
@@ -68,6 +68,11 @@ protected:
     return job_time_;
   }
 
+  OpenGLBackend* backend()
+  {
+    return &backend_;
+  }
+
 private:
   ViewerOutput* viewer_;
 
diff --git a/app/widget/timelinewidget/timelinewidget.cpp b/app/widget/timelinewidget/timelinewidget.cpp
index 95c982e4a..9c0b0e35d 100644
--- a/app/widget/timelinewidget/timelinewidget.cpp
+++ b/app/widget/timelinewidget/timelinewidget.cpp
@@ -981,40 +981,33 @@ void TimelineWidget::ViewDragDropped(TimelineViewMouseEvent *event)
 
 void TimelineWidget::AddBlock(Block *block, TrackReference track)
 {
-  switch (block->type()) {
-  case Block::kClip:
-  case Block::kTransition:
-  case Block::kGap:
-  {
-    // Set up clip with view parameters (clip item will automatically size its rect accordingly)
-    TimelineViewBlockItem* item = new TimelineViewBlockItem(block);
+  // Set up clip with view parameters (clip item will automatically size its rect accordingly)
+  TimelineViewBlockItem* item = new TimelineViewBlockItem(block);
 
-    item->SetYCoords(GetTrackY(track), GetTrackHeight(track));
-    item->SetScale(GetScale());
-    item->SetTrack(track);
-    item->SetTimebase(timebase());
+  item->SetYCoords(GetTrackY(track), GetTrackHeight(track));
+  item->SetScale(GetScale());
+  item->SetTrack(track);
+  item->SetTimebase(timebase());
 
-    // Add to list of clip items that can be iterated through
-    block_items_.insert(block, item);
+  // Add to list of clip items that can be iterated through
+  block_items_.insert(block, item);
 
-    // Add item to graphics scene
-    views_.at(track.type())->view()->scene()->addItem(item);
+  // Add item to graphics scene
+  views_.at(track.type())->view()->scene()->addItem(item);
 
-    connect(block, &Block::Refreshed, this, &TimelineWidget::BlockChanged);
-    connect(block, &Block::LinksChanged, this, &TimelineWidget::PreviewUpdated);
-    connect(block, &Block::NameChanged, this, &TimelineWidget::PreviewUpdated);
-    connect(block, &Block::EnabledChanged, this, &TimelineWidget::PreviewUpdated);
-
-    if (block->type() == Block::kClip) {
-      connect(static_cast<ClipBlock*>(block), &ClipBlock::PreviewUpdated, this, &TimelineWidget::PreviewUpdated);
-    }
-    break;
-  }
-  }
+  connect(block, &Block::Refreshed, this, &TimelineWidget::BlockRefreshed);
+  connect(block, &Block::LinksChanged, this, &TimelineWidget::BlockUpdated);
+  connect(block, &Block::NameChanged, this, &TimelineWidget::BlockUpdated);
+  connect(block, &Block::EnabledChanged, this, &TimelineWidget::BlockUpdated);
 }
 
 void TimelineWidget::RemoveBlock(Block *block)
 {
+  disconnect(block, &Block::Refreshed, this, &TimelineWidget::BlockRefreshed);
+  disconnect(block, &Block::LinksChanged, this, &TimelineWidget::BlockUpdated);
+  disconnect(block, &Block::NameChanged, this, &TimelineWidget::BlockUpdated);
+  disconnect(block, &Block::EnabledChanged, this, &TimelineWidget::BlockUpdated);
+
   delete block_items_.take(block);
 }
 
@@ -1025,11 +1018,13 @@ void TimelineWidget::AddTrack(TrackOutput *track, Timeline::TrackType type)
   }
 
   connect(track, &TrackOutput::IndexChanged, this, &TimelineWidget::TrackIndexChanged);
+  connect(track, &TrackOutput::PreviewChanged, this, &TimelineWidget::TrackPreviewUpdated);
 }
 
 void TimelineWidget::RemoveTrack(TrackOutput *track)
 {
   disconnect(track, &TrackOutput::IndexChanged, this, &TimelineWidget::TrackIndexChanged);
+  disconnect(track, &TrackOutput::PreviewChanged, this, &TimelineWidget::TrackPreviewUpdated);
 
   foreach (Block* b, track->Blocks()) {
     RemoveBlock(b);
@@ -1065,7 +1060,7 @@ void TimelineWidget::ViewSelectionChanged()
   emit SelectionChanged(selected_blocks);
 }
 
-void TimelineWidget::BlockChanged()
+void TimelineWidget::BlockRefreshed()
 {
   TimelineViewRect* rect = block_items_.value(static_cast<Block*>(sender()));
 
@@ -1074,7 +1069,7 @@ void TimelineWidget::BlockChanged()
   }
 }
 
-void TimelineWidget::PreviewUpdated()
+void TimelineWidget::BlockUpdated()
 {
   TimelineViewRect* rect = block_items_.value(static_cast<Block*>(sender()));
 
@@ -1083,6 +1078,20 @@ void TimelineWidget::PreviewUpdated()
   }
 }
 
+void TimelineWidget::TrackPreviewUpdated()
+{
+  QMap<Block*, TimelineViewBlockItem*>::const_iterator i;
+
+  TrackOutput* track = static_cast<TrackOutput*>(sender());
+  TrackReference track_ref(track->track_type(), track->Index());
+
+  for (i=block_items_.constBegin(); i!=block_items_.constEnd(); i++) {
+    if (i.value()->Track() == track_ref) {
+      i.value()->update();
+    }
+  }
+}
+
 void TimelineWidget::UpdateHorizontalSplitters()
 {
   QSplitter* sender_splitter = static_cast<QSplitter*>(sender());
diff --git a/app/widget/timelinewidget/timelinewidget.h b/app/widget/timelinewidget/timelinewidget.h
index 94251d0bc..d0eed8496 100644
--- a/app/widget/timelinewidget/timelinewidget.h
+++ b/app/widget/timelinewidget/timelinewidget.h
@@ -528,9 +528,11 @@ private slots:
    * This slot does a static_cast on sender() to Block*, meaning all objects triggering this slot must be Blocks or
    * derivatives.
    */
-  void BlockChanged();
+  void BlockRefreshed();
 
-  void PreviewUpdated();
+  void BlockUpdated();
+
+  void TrackPreviewUpdated();
 
   void UpdateHorizontalSplitters();
 
diff --git a/app/widget/timelinewidget/undo/undo.cpp b/app/widget/timelinewidget/undo/undo.cpp
index 282b4d587..d447bca77 100644
--- a/app/widget/timelinewidget/undo/undo.cpp
+++ b/app/widget/timelinewidget/undo/undo.cpp
@@ -210,10 +210,6 @@ void TrackRippleRemoveAreaCommand::redo_internal()
     // Split the block here
     trim_in_ = static_cast<Block*>(trim_out_->copy());
 
-    if (trim_out_->type() == Block::kClip) {
-      static_cast<ClipBlock*>(trim_in_)->set_waveform(static_cast<ClipBlock*>(trim_out_)->waveform());
-    }
-
     static_cast<NodeGraph*>(track_->parent())->AddNode(trim_in_);
     Node::CopyInputs(trim_out_, trim_in_);
 
@@ -299,11 +295,6 @@ void TrackRippleRemoveAreaCommand::undo_internal()
     track_->RippleRemoveBlock(trim_in_);
     trim_out_->set_length_and_media_out(trim_out_old_length_);
 
-    if (trim_out_->type() == Block::kClip) {
-      static_cast<ClipBlock*>(trim_out_)->waveform().OverwriteSums(static_cast<ClipBlock*>(trim_in_)->waveform(),
-                                                                   out_ - trim_out_->in());
-    }
-
     delete TakeNodeFromParentGraph(trim_in_);
 
   } else {
@@ -448,20 +439,10 @@ void BlockSplitCommand::redo_internal()
 
   rational new_part_length = block_->length() - (point_ - block_->in());
 
-  AudioVisualWaveform split_waveform;
-
-  if (block_->type() == Block::kClip) {
-    split_waveform = static_cast<ClipBlock*>(block_)->waveform().Mid(new_length_);
-  }
-
   block_->set_length_and_media_out(new_length_);
 
   new_block_->set_length_and_media_in(new_part_length);
 
-  if (block_->type() == Block::kClip) {
-    static_cast<ClipBlock*>(new_block_)->set_waveform(split_waveform);
-  }
-
   track_->InsertBlockAfter(new_block_, block_);
 
   foreach (NodeInput* transition, transitions_to_move_) {
@@ -486,11 +467,6 @@ void BlockSplitCommand::undo_internal()
     NodeParam::ConnectEdge(block_->output(), transition);
   }
 
-  if (block_->type() == Block::kClip) {
-    static_cast<ClipBlock*>(block_)->waveform().OverwriteSums(static_cast<ClipBlock*>(new_block_)->waveform(),
-                                                              new_length_);
-  }
-
   track_->UnblockInvalidateCache();
 }
 
@@ -623,102 +599,6 @@ Project *BlockSplitPreservingLinksCommand::GetRelevantProject() const
   return static_cast<Sequence*>(blocks_.first()->parent())->project();
 }
 
-/*
-TrackCleanGapsCommand::TrackCleanGapsCommand(TrackList *track_list, int index, QUndoCommand *parent) :
-  UndoCommand(parent),
-  track_list_(track_list),
-  track_index_(index)
-{
-}
-
-Project *TrackCleanGapsCommand::GetRelevantProject() const
-{
-  return static_cast<Sequence*>(track_list_->GetParentGraph())->project();
-}
-
-void TrackCleanGapsCommand::redo_internal()
-{
-  GapBlock* on_gap = nullptr;
-  QList<GapBlock*> consecutive_gaps;
-
-  TrackOutput* track = track_list_->GetTrackAt(track_index_);
-
-  // We can block the IC signal because merging gaps won't actually change anything
-  track->BlockInvalidateCache();
-
-  foreach (Block* b, track->Blocks()) {
-    if (b->type() == Block::kGap) {
-      if (on_gap) {
-        consecutive_gaps.append(static_cast<GapBlock*>(b));
-      } else {
-        on_gap = static_cast<GapBlock*>(b);
-      }
-    } else if (on_gap) {
-      merged_gaps_.append({on_gap, on_gap->length(), consecutive_gaps});
-
-      // Remove each gap and add to the length of the merged
-      rational new_gap_length = on_gap->length();
-      foreach (GapBlock* gap, consecutive_gaps) {
-        track->RippleRemoveBlock(gap);
-        static_cast<NodeGraph*>(track->parent())->TakeNode(gap, &memory_manager_);
-
-        new_gap_length += gap->length();
-      }
-      on_gap->set_length_and_media_out(new_gap_length);
-
-      // Reset state
-      on_gap = nullptr;
-      consecutive_gaps.clear();
-    }
-  }
-
-  if (on_gap) {
-    // If we're here, we found at least one or several
-    removed_end_gaps_.append(on_gap);
-    removed_end_gaps_.append(consecutive_gaps);
-
-    foreach (GapBlock* gap, removed_end_gaps_) {
-      track->RippleRemoveBlock(gap);
-      static_cast<NodeGraph*>(track->parent())->TakeNode(gap, &memory_manager_);
-    }
-  }
-
-  track->UnblockInvalidateCache();
-}
-
-void TrackCleanGapsCommand::undo_internal()
-{
-  TrackOutput* track = track_list_->GetTrackAt(track_index_);
-
-  track->BlockInvalidateCache();
-
-  // Restored removed end gaps
-  foreach (GapBlock* gap, removed_end_gaps_) {
-    static_cast<NodeGraph*>(track->parent())->AddNode(gap);
-    track->AppendBlock(gap);
-  }
-  removed_end_gaps_.clear();
-
-  for (int i=merged_gaps_.size()-1;i>=0;i--) {
-    const MergedGap& merge_info = merged_gaps_.at(i);
-
-    merge_info.merged->set_length_and_media_out(merge_info.original_length);
-
-    GapBlock* last_gap_added = merge_info.merged;
-
-    foreach (GapBlock* gap, merge_info.removed) {
-      static_cast<NodeGraph*>(track->parent())->AddNode(gap);
-      track->InsertBlockAfter(gap, last_gap_added);
-      last_gap_added = gap;
-    }
-  }
-
-  track->UnblockInvalidateCache();
-
-  merged_gaps_.clear();
-}
-*/
-
 BlockSetSpeedCommand::BlockSetSpeedCommand(Block *block, const rational &new_speed, QUndoCommand *parent) :
   UndoCommand(parent),
   block_(block),
@@ -1203,7 +1083,7 @@ void TrackReplaceBlockWithGapCommand::undo_internal()
   } else {
 
     // If there's no `gap_`, we must have removed the block at the end
-    invalidate_range = TimeRange(track_->length(), RATIONAL_MAX);
+    invalidate_range = TimeRange(track_->track_length(), RATIONAL_MAX);
 
     if (merged_gap_) {
       static_cast<NodeGraph*>(track_->parent())->AddNode(merged_gap_);
diff --git a/app/widget/timelinewidget/undo/undo.h b/app/widget/timelinewidget/undo/undo.h
index 892c21daa..511fffdb2 100644
--- a/app/widget/timelinewidget/undo/undo.h
+++ b/app/widget/timelinewidget/undo/undo.h
@@ -420,37 +420,6 @@ private:
 
 };
 
-/*
-class TrackCleanGapsCommand : public UndoCommand {
-public:
-  TrackCleanGapsCommand(TrackList* track_list, int index, QUndoCommand* parent = nullptr);
-
-  virtual Project* GetRelevantProject() const override;
-
-protected:
-  virtual void redo_internal() override;
-  virtual void undo_internal() override;
-
-private:
-  struct MergedGap {
-    GapBlock* merged;
-    rational original_length;
-    QList<GapBlock*> removed;
-  };
-
-  TrackList* track_list_;
-
-  int track_index_;
-
-  QObject memory_manager_;
-
-  QList<MergedGap> merged_gaps_;
-
-  QList<GapBlock*> removed_end_gaps_;
-
-};
-*/
-
 class TimelineRippleDeleteGapsAtRegionsCommand : public UndoCommand {
 public:
   TimelineRippleDeleteGapsAtRegionsCommand(ViewerOutput* vo, const TimeRangeList& regions, QUndoCommand* parent = nullptr);
diff --git a/app/widget/timelinewidget/view/timelineviewblockitem.cpp b/app/widget/timelinewidget/view/timelineviewblockitem.cpp
index 48df43b20..8195fa4b7 100644
--- a/app/widget/timelinewidget/view/timelineviewblockitem.cpp
+++ b/app/widget/timelinewidget/view/timelineviewblockitem.cpp
@@ -97,10 +97,14 @@ void TimelineViewBlockItem::paint(QPainter *painter, const QStyleOptionGraphicsI
 
     // Draw waveform if one is available
     painter->setPen(QColor(64, 64, 64));
-    AudioVisualWaveform::DrawWaveform(painter,
-                                      rect().toRect(),
-                                      this->GetScale(),
-                                      static_cast<ClipBlock*>(block_)->waveform());
+    TrackOutput* track = TrackOutput::TrackFromBlock(block_);
+    if (track) {
+      AudioVisualWaveform::DrawWaveform(painter,
+                                        rect().toRect(),
+                                        this->GetScale(),
+                                        track->waveform(),
+                                        block_->in());
+    }
 
     painter->setPen(Qt::white);
     painter->drawLine(rect().topLeft(), QPointF(rect().right(), rect().top()));