diff --git a/app/node/output/viewer/viewer.cpp b/app/node/output/viewer/viewer.cpp
index 45fd6b23d..b5b0f495b 100644
--- a/app/node/output/viewer/viewer.cpp
+++ b/app/node/output/viewer/viewer.cpp
@@ -24,7 +24,9 @@
 
 OLIVE_NAMESPACE_ENTER
 
-ViewerOutput::ViewerOutput()
+ViewerOutput::ViewerOutput() :
+  video_frame_cache_(this),
+  audio_playback_cache_(this)
 {
   texture_input_ = new NodeInput("tex_in", NodeInput::kTexture);
   AddInput(texture_input_);
diff --git a/app/render/audioplaybackcache.cpp b/app/render/audioplaybackcache.cpp
index 98503223e..73e76a067 100644
--- a/app/render/audioplaybackcache.cpp
+++ b/app/render/audioplaybackcache.cpp
@@ -28,7 +28,8 @@
 
 OLIVE_NAMESPACE_ENTER
 
-AudioPlaybackCache::AudioPlaybackCache()
+AudioPlaybackCache::AudioPlaybackCache(QObject* parent) :
+  PlaybackCache(parent)
 {
   quint32 r = std::rand();
   UpdateFilename(QString::number(r));
diff --git a/app/render/audioplaybackcache.h b/app/render/audioplaybackcache.h
index 9e1328fbc..5fdb224df 100644
--- a/app/render/audioplaybackcache.h
+++ b/app/render/audioplaybackcache.h
@@ -31,7 +31,7 @@ class AudioPlaybackCache : public PlaybackCache
 {
   Q_OBJECT
 public:
-  AudioPlaybackCache();
+  AudioPlaybackCache(QObject* parent = nullptr);
 
   AudioParams GetParameters() {
     QMutexLocker locker(lock());
diff --git a/app/render/framehashcache.h b/app/render/framehashcache.h
index a31c4335c..96878059e 100644
--- a/app/render/framehashcache.h
+++ b/app/render/framehashcache.h
@@ -35,12 +35,13 @@ class FrameHashCache : public PlaybackCache
 {
   Q_OBJECT
 public:
-  FrameHashCache() = default;
+  FrameHashCache(QObject* parent = nullptr) :
+    PlaybackCache(parent)
+  {
+  }
 
   QByteArray GetHash(const rational& time);
 
-  void SetHash(const rational& time, const QByteArray& hash, const qint64 &job_time);
-
   void SetTimebase(const rational& tb);
 
   /**
@@ -72,6 +73,9 @@ public:
   QVector<rational> GetFrameListFromTimeRange(const TimeRangeList &range);
   QVector<rational> GetInvalidatedFrames();
 
+public slots:
+  void SetHash(const OLIVE_NAMESPACE::rational& time, const QByteArray& hash, const qint64 &job_time);
+
 protected:
   virtual void LengthChangedEvent(const rational& old, const rational& newlen) override;
 
diff --git a/app/render/playbackcache.h b/app/render/playbackcache.h
index f73cefb9f..ce54bdd7e 100644
--- a/app/render/playbackcache.h
+++ b/app/render/playbackcache.h
@@ -32,7 +32,10 @@ class PlaybackCache : public QObject
 {
   Q_OBJECT
 public:
-  PlaybackCache() = default;
+  PlaybackCache(QObject* parent = nullptr) :
+    QObject(parent)
+  {
+  }
 
   void Invalidate(const TimeRange& r);