diff --git a/src/filter/FilterConfig.cxx b/src/filter/FilterConfig.cxx
index 61a23797a..380a65020 100644
--- a/src/filter/FilterConfig.cxx
+++ b/src/filter/FilterConfig.cxx
@@ -19,8 +19,9 @@
 
 #include "config.h"
 #include "FilterConfig.hxx"
-#include "plugins/ChainFilterPlugin.hxx"
 #include "FilterPlugin.hxx"
+#include "FilterInternal.hxx"
+#include "plugins/ChainFilterPlugin.hxx"
 #include "config/Param.hxx"
 #include "config/ConfigOption.hxx"
 #include "config/ConfigGlobal.hxx"
@@ -42,11 +43,11 @@ filter_chain_append_new(PreparedFilter &chain, const char *template_name)
 					 template_name);
 
 	// Instantiate one of those filter plugins with the template name as a hint
-	PreparedFilter *f = filter_configured_new(*cfg);
+	auto f = filter_configured_new(*cfg);
 
 	const char *plugin_name = cfg->GetBlockValue("plugin",
 						     "unknown");
-	filter_chain_append(chain, plugin_name, f);
+	filter_chain_append(chain, plugin_name, std::move(f));
 }
 
 void
diff --git a/src/filter/FilterPlugin.cxx b/src/filter/FilterPlugin.cxx
index 11326e09f..5f5ad5d8c 100644
--- a/src/filter/FilterPlugin.cxx
+++ b/src/filter/FilterPlugin.cxx
@@ -20,13 +20,14 @@
 #include "config.h"
 #include "FilterPlugin.hxx"
 #include "FilterRegistry.hxx"
+#include "FilterInternal.hxx"
 #include "config/Block.hxx"
 #include "config/ConfigError.hxx"
 #include "util/RuntimeError.hxx"
 
 #include <assert.h>
 
-PreparedFilter *
+std::unique_ptr<PreparedFilter>
 filter_new(const FilterPlugin *plugin, const ConfigBlock &block)
 {
 	assert(plugin != nullptr);
@@ -34,7 +35,7 @@ filter_new(const FilterPlugin *plugin, const ConfigBlock &block)
 	return plugin->init(block);
 }
 
-PreparedFilter *
+std::unique_ptr<PreparedFilter>
 filter_configured_new(const ConfigBlock &block)
 {
 	const char *plugin_name = block.GetBlockValue("plugin");
diff --git a/src/filter/FilterPlugin.hxx b/src/filter/FilterPlugin.hxx
index 37d45f3ef..cb7f82476 100644
--- a/src/filter/FilterPlugin.hxx
+++ b/src/filter/FilterPlugin.hxx
@@ -26,6 +26,8 @@
 #ifndef MPD_FILTER_PLUGIN_HXX
 #define MPD_FILTER_PLUGIN_HXX
 
+#include <memory>
+
 struct ConfigBlock;
 class PreparedFilter;
 
@@ -35,7 +37,7 @@ struct FilterPlugin {
 	/**
          * Allocates and configures a filter.
 	 */
-	PreparedFilter *(*init)(const ConfigBlock &block);
+	std::unique_ptr<PreparedFilter> (*init)(const ConfigBlock &block);
 };
 
 /**
@@ -46,7 +48,7 @@ struct FilterPlugin {
  * @param plugin the filter plugin
  * @param block configuration section
  */
-PreparedFilter *
+std::unique_ptr<PreparedFilter>
 filter_new(const FilterPlugin *plugin,
 	   const ConfigBlock &block);
 
@@ -58,7 +60,7 @@ filter_new(const FilterPlugin *plugin,
  *
  * @param block the configuration section
  */
-PreparedFilter *
+std::unique_ptr<PreparedFilter>
 filter_configured_new(const ConfigBlock &block);
 
 #endif
diff --git a/src/filter/Observer.cxx b/src/filter/Observer.cxx
index 5d6602d46..706abd8b7 100644
--- a/src/filter/Observer.cxx
+++ b/src/filter/Observer.cxx
@@ -27,21 +27,20 @@
 class FilterObserver::PreparedProxy final : public PreparedFilter {
 	FilterObserver &observer;
 
-	PreparedFilter *const prepared_filter;
+	std::unique_ptr<PreparedFilter> prepared_filter;
 	Proxy *child = nullptr;
 
 public:
 	PreparedProxy(FilterObserver &_observer,
-		      PreparedFilter *_prepared_filter)
+		      std::unique_ptr<PreparedFilter> _prepared_filter)
 		:observer(_observer),
-		 prepared_filter(_prepared_filter) {}
+		 prepared_filter(std::move(_prepared_filter)) {}
 
 	~PreparedProxy() {
 		assert(child == nullptr);
 		assert(observer.proxy == this);
 
 		observer.proxy = nullptr;
-		delete prepared_filter;
 	}
 
 	void Clear(gcc_unused Proxy *_child) {
@@ -95,12 +94,14 @@ FilterObserver::PreparedProxy::Open(AudioFormat &af)
 	return child = new Proxy(*this, f);
 }
 
-PreparedFilter *
-FilterObserver::Set(PreparedFilter *pf)
+std::unique_ptr<PreparedFilter>
+FilterObserver::Set(std::unique_ptr<PreparedFilter> pf)
 {
 	assert(proxy == nullptr);
 
-	return proxy = new PreparedProxy(*this, pf);
+	auto p = std::make_unique<PreparedProxy>(*this, std::move(pf));
+	proxy = p.get();
+	return p;
 }
 
 Filter *
diff --git a/src/filter/Observer.hxx b/src/filter/Observer.hxx
index 276012bd8..b2114d1d0 100644
--- a/src/filter/Observer.hxx
+++ b/src/filter/Observer.hxx
@@ -22,6 +22,8 @@
 
 #include "check.h"
 
+#include <memory>
+
 class PreparedFilter;
 class Filter;
 
@@ -39,7 +41,7 @@ public:
 	/**
 	 * @return a proxy object
 	 */
-	PreparedFilter *Set(PreparedFilter *pf);
+	std::unique_ptr<PreparedFilter> Set(std::unique_ptr<PreparedFilter> pf);
 
 	Filter *Get();
 };
diff --git a/src/filter/plugins/AutoConvertFilterPlugin.cxx b/src/filter/plugins/AutoConvertFilterPlugin.cxx
index 890018243..f805b6183 100644
--- a/src/filter/plugins/AutoConvertFilterPlugin.cxx
+++ b/src/filter/plugins/AutoConvertFilterPlugin.cxx
@@ -62,13 +62,11 @@ class PreparedAutoConvertFilter final : public PreparedFilter {
 	/**
 	 * The underlying filter.
 	 */
-	PreparedFilter *const filter;
+	std::unique_ptr<PreparedFilter> filter;
 
 public:
-	PreparedAutoConvertFilter(PreparedFilter *_filter):filter(_filter) {}
-	~PreparedAutoConvertFilter() {
-		delete filter;
-	}
+	PreparedAutoConvertFilter(std::unique_ptr<PreparedFilter> _filter) noexcept
+		:filter(std::move(_filter)) {}
 
 	Filter *Open(AudioFormat &af) override;
 };
@@ -106,8 +104,8 @@ AutoConvertFilter::FilterPCM(ConstBuffer<void> src)
 	return filter->FilterPCM(src);
 }
 
-PreparedFilter *
-autoconvert_filter_new(PreparedFilter *filter)
+std::unique_ptr<PreparedFilter>
+autoconvert_filter_new(std::unique_ptr<PreparedFilter> filter) noexcept
 {
-	return new PreparedAutoConvertFilter(filter);
+	return std::make_unique<PreparedAutoConvertFilter>(std::move(filter));
 }
diff --git a/src/filter/plugins/AutoConvertFilterPlugin.hxx b/src/filter/plugins/AutoConvertFilterPlugin.hxx
index e2bd6917e..de8e87509 100644
--- a/src/filter/plugins/AutoConvertFilterPlugin.hxx
+++ b/src/filter/plugins/AutoConvertFilterPlugin.hxx
@@ -20,6 +20,8 @@
 #ifndef MPD_AUTOCONVERT_FILTER_PLUGIN_HXX
 #define MPD_AUTOCONVERT_FILTER_PLUGIN_HXX
 
+#include <memory>
+
 class PreparedFilter;
 
 /**
@@ -28,7 +30,7 @@ class PreparedFilter;
  * requests a different format, it automatically creates a
  * convert_filter.
  */
-PreparedFilter *
-autoconvert_filter_new(PreparedFilter *filter);
+std::unique_ptr<PreparedFilter>
+autoconvert_filter_new(std::unique_ptr<PreparedFilter> filter) noexcept;
 
 #endif
diff --git a/src/filter/plugins/ChainFilterPlugin.cxx b/src/filter/plugins/ChainFilterPlugin.cxx
index b3ac2fdbf..0349301b0 100644
--- a/src/filter/plugins/ChainFilterPlugin.cxx
+++ b/src/filter/plugins/ChainFilterPlugin.cxx
@@ -67,13 +67,11 @@ public:
 class PreparedChainFilter final : public PreparedFilter {
 	struct Child {
 		const char *name;
-		PreparedFilter *filter;
+		std::unique_ptr<PreparedFilter> filter;
 
-		Child(const char *_name, PreparedFilter *_filter)
-			:name(_name), filter(_filter) {}
-		~Child() {
-			delete filter;
-		}
+		Child(const char *_name,
+		      std::unique_ptr<PreparedFilter> _filter)
+			:name(_name), filter(std::move(_filter)) {}
 
 		Child(const Child &) = delete;
 		Child &operator=(const Child &) = delete;
@@ -84,8 +82,9 @@ class PreparedChainFilter final : public PreparedFilter {
 	std::list<Child> children;
 
 public:
-	void Append(const char *name, PreparedFilter *filter) {
-		children.emplace_back(name, filter);
+	void Append(const char *name,
+		    std::unique_ptr<PreparedFilter> filter) noexcept {
+		children.emplace_back(name, std::move(filter));
 	}
 
 	/* virtual methods from class PreparedFilter */
@@ -143,17 +142,17 @@ ChainFilter::FilterPCM(ConstBuffer<void> src)
 	return src;
 }
 
-PreparedFilter *
-filter_chain_new(void)
+std::unique_ptr<PreparedFilter>
+filter_chain_new() noexcept
 {
-	return new PreparedChainFilter();
+	return std::make_unique<PreparedChainFilter>();
 }
 
 void
 filter_chain_append(PreparedFilter &_chain, const char *name,
-		    PreparedFilter *filter)
+		    std::unique_ptr<PreparedFilter> filter) noexcept
 {
 	PreparedChainFilter &chain = (PreparedChainFilter &)_chain;
 
-	chain.Append(name, filter);
+	chain.Append(name, std::move(filter));
 }
diff --git a/src/filter/plugins/ChainFilterPlugin.hxx b/src/filter/plugins/ChainFilterPlugin.hxx
index 15814281d..c5b4c810d 100644
--- a/src/filter/plugins/ChainFilterPlugin.hxx
+++ b/src/filter/plugins/ChainFilterPlugin.hxx
@@ -27,13 +27,15 @@
 #ifndef MPD_FILTER_CHAIN_HXX
 #define MPD_FILTER_CHAIN_HXX
 
+#include <memory>
+
 class PreparedFilter;
 
 /**
  * Creates a new filter chain.
  */
-PreparedFilter *
-filter_chain_new();
+std::unique_ptr<PreparedFilter>
+filter_chain_new() noexcept;
 
 /**
  * Appends a new filter at the end of the filter chain.  You must call
@@ -44,6 +46,6 @@ filter_chain_new();
  */
 void
 filter_chain_append(PreparedFilter &chain, const char *name,
-		    PreparedFilter *filter);
+		    std::unique_ptr<PreparedFilter> filter) noexcept;
 
 #endif
diff --git a/src/filter/plugins/ConvertFilterPlugin.cxx b/src/filter/plugins/ConvertFilterPlugin.cxx
index dc6fedf82..571f68e6e 100644
--- a/src/filter/plugins/ConvertFilterPlugin.cxx
+++ b/src/filter/plugins/ConvertFilterPlugin.cxx
@@ -119,10 +119,10 @@ ConvertFilter::FilterPCM(ConstBuffer<void> src)
 	return state.Convert(src);
 }
 
-PreparedFilter *
+std::unique_ptr<PreparedFilter>
 convert_filter_prepare() noexcept
 {
-	return new PreparedConvertFilter();
+	return std::make_unique<PreparedConvertFilter>();
 }
 
 Filter *
diff --git a/src/filter/plugins/ConvertFilterPlugin.hxx b/src/filter/plugins/ConvertFilterPlugin.hxx
index 469271c93..26e472099 100644
--- a/src/filter/plugins/ConvertFilterPlugin.hxx
+++ b/src/filter/plugins/ConvertFilterPlugin.hxx
@@ -20,11 +20,13 @@
 #ifndef MPD_CONVERT_FILTER_PLUGIN_HXX
 #define MPD_CONVERT_FILTER_PLUGIN_HXX
 
+#include <memory>
+
 class PreparedFilter;
 class Filter;
 struct AudioFormat;
 
-PreparedFilter *
+std::unique_ptr<PreparedFilter>
 convert_filter_prepare() noexcept;
 
 Filter *
diff --git a/src/filter/plugins/NormalizeFilterPlugin.cxx b/src/filter/plugins/NormalizeFilterPlugin.cxx
index 4cd68b074..16119086b 100644
--- a/src/filter/plugins/NormalizeFilterPlugin.cxx
+++ b/src/filter/plugins/NormalizeFilterPlugin.cxx
@@ -53,10 +53,10 @@ public:
 	Filter *Open(AudioFormat &af) override;
 };
 
-static PreparedFilter *
+static std::unique_ptr<PreparedFilter>
 normalize_filter_init(gcc_unused const ConfigBlock &block)
 {
-	return new PreparedNormalizeFilter();
+	return std::make_unique<PreparedNormalizeFilter>();
 }
 
 Filter *
@@ -82,8 +82,8 @@ const FilterPlugin normalize_filter_plugin = {
 	normalize_filter_init,
 };
 
-PreparedFilter *
+std::unique_ptr<PreparedFilter>
 normalize_filter_prepare() noexcept
 {
-	return new PreparedNormalizeFilter();
+	return std::make_unique<PreparedNormalizeFilter>();
 }
diff --git a/src/filter/plugins/NormalizeFilterPlugin.hxx b/src/filter/plugins/NormalizeFilterPlugin.hxx
index fb62575d8..3c9101341 100644
--- a/src/filter/plugins/NormalizeFilterPlugin.hxx
+++ b/src/filter/plugins/NormalizeFilterPlugin.hxx
@@ -20,11 +20,13 @@
 #ifndef MPD_NORMALIZE_FILTER_PLUGIN_HXX
 #define MPD_NORMALIZE_FILTER_PLUGIN_HXX
 
+#include <memory>
+
 class PreparedFilter;
 class Filter;
 struct AudioFormat;
 
-PreparedFilter *
+std::unique_ptr<PreparedFilter>
 normalize_filter_prepare() noexcept;
 
 #endif
diff --git a/src/filter/plugins/NullFilterPlugin.cxx b/src/filter/plugins/NullFilterPlugin.cxx
index 09599d156..7856494bd 100644
--- a/src/filter/plugins/NullFilterPlugin.cxx
+++ b/src/filter/plugins/NullFilterPlugin.cxx
@@ -48,10 +48,10 @@ public:
 	}
 };
 
-static PreparedFilter *
+static std::unique_ptr<PreparedFilter>
 null_filter_init(gcc_unused const ConfigBlock &block)
 {
-	return new PreparedNullFilter();
+	return std::make_unique<PreparedNullFilter>();
 }
 
 const FilterPlugin null_filter_plugin = {
diff --git a/src/filter/plugins/ReplayGainFilterPlugin.cxx b/src/filter/plugins/ReplayGainFilterPlugin.cxx
index 1a77d44dc..0a74bb13c 100644
--- a/src/filter/plugins/ReplayGainFilterPlugin.cxx
+++ b/src/filter/plugins/ReplayGainFilterPlugin.cxx
@@ -171,10 +171,10 @@ ReplayGainFilter::Update()
 		pv.SetVolume(volume);
 }
 
-PreparedFilter *
-NewReplayGainFilter(const ReplayGainConfig &config)
+std::unique_ptr<PreparedFilter>
+NewReplayGainFilter(const ReplayGainConfig &config) noexcept
 {
-	return new PreparedReplayGainFilter(config);
+	return std::make_unique<PreparedReplayGainFilter>(config);
 }
 
 Filter *
diff --git a/src/filter/plugins/ReplayGainFilterPlugin.hxx b/src/filter/plugins/ReplayGainFilterPlugin.hxx
index 5a295491d..2177537b3 100644
--- a/src/filter/plugins/ReplayGainFilterPlugin.hxx
+++ b/src/filter/plugins/ReplayGainFilterPlugin.hxx
@@ -22,14 +22,16 @@
 
 #include "ReplayGainMode.hxx"
 
+#include <memory>
+
 class Filter;
 class PreparedFilter;
 class Mixer;
 struct ReplayGainConfig;
 struct ReplayGainInfo;
 
-PreparedFilter *
-NewReplayGainFilter(const ReplayGainConfig &config);
+std::unique_ptr<PreparedFilter>
+NewReplayGainFilter(const ReplayGainConfig &config) noexcept;
 
 /**
  * Enables or disables the hardware mixer for applying replay gain.
diff --git a/src/filter/plugins/RouteFilterPlugin.cxx b/src/filter/plugins/RouteFilterPlugin.cxx
index 682dd06a3..98181800a 100644
--- a/src/filter/plugins/RouteFilterPlugin.cxx
+++ b/src/filter/plugins/RouteFilterPlugin.cxx
@@ -196,10 +196,10 @@ PreparedRouteFilter::PreparedRouteFilter(const ConfigBlock &block)
 	}
 }
 
-static PreparedFilter *
+static std::unique_ptr<PreparedFilter>
 route_filter_init(const ConfigBlock &block)
 {
-	return new PreparedRouteFilter(block);
+	return std::make_unique<PreparedRouteFilter>(block);
 }
 
 RouteFilter::RouteFilter(const AudioFormat &audio_format,
diff --git a/src/filter/plugins/VolumeFilterPlugin.cxx b/src/filter/plugins/VolumeFilterPlugin.cxx
index 81282dcc1..2c7addbd1 100644
--- a/src/filter/plugins/VolumeFilterPlugin.cxx
+++ b/src/filter/plugins/VolumeFilterPlugin.cxx
@@ -65,10 +65,10 @@ VolumeFilter::FilterPCM(ConstBuffer<void> src)
 	return pv.Apply(src);
 }
 
-PreparedFilter *
+std::unique_ptr<PreparedFilter>
 volume_filter_prepare() noexcept
 {
-	return new PreparedVolumeFilter();
+	return std::make_unique<PreparedVolumeFilter>();
 }
 
 unsigned
diff --git a/src/filter/plugins/VolumeFilterPlugin.hxx b/src/filter/plugins/VolumeFilterPlugin.hxx
index 1f7280ab9..6091663f7 100644
--- a/src/filter/plugins/VolumeFilterPlugin.hxx
+++ b/src/filter/plugins/VolumeFilterPlugin.hxx
@@ -20,10 +20,12 @@
 #ifndef MPD_VOLUME_FILTER_PLUGIN_HXX
 #define MPD_VOLUME_FILTER_PLUGIN_HXX
 
+#include <memory>
+
 class PreparedFilter;
 class Filter;
 
-PreparedFilter *
+std::unique_ptr<PreparedFilter>
 volume_filter_prepare() noexcept;
 
 unsigned
diff --git a/src/output/Filtered.hxx b/src/output/Filtered.hxx
index 34ac4de38..59ab78e3f 100644
--- a/src/output/Filtered.hxx
+++ b/src/output/Filtered.hxx
@@ -93,7 +93,7 @@ public:
 	 * The filter object of this audio output.  This is an
 	 * instance of chain_filter_plugin.
 	 */
-	PreparedFilter *prepared_filter = nullptr;
+	std::unique_ptr<PreparedFilter> prepared_filter;
 
 	/**
 	 * The #VolumeFilter instance of this audio output.  It is
@@ -105,14 +105,14 @@ public:
 	 * The replay_gain_filter_plugin instance of this audio
 	 * output.
 	 */
-	PreparedFilter *prepared_replay_gain_filter = nullptr;
+	std::unique_ptr<PreparedFilter> prepared_replay_gain_filter;
 
 	/**
 	 * The replay_gain_filter_plugin instance of this audio
 	 * output, to be applied to the second chunk during
 	 * cross-fading.
 	 */
-	PreparedFilter *prepared_other_replay_gain_filter = nullptr;
+	std::unique_ptr<PreparedFilter> prepared_other_replay_gain_filter;
 
 	/**
 	 * The convert_filter_plugin instance of this audio output.
diff --git a/src/output/Finish.cxx b/src/output/Finish.cxx
index 9e1c4eb46..a3714586f 100644
--- a/src/output/Finish.cxx
+++ b/src/output/Finish.cxx
@@ -27,10 +27,6 @@ FilteredAudioOutput::~FilteredAudioOutput()
 {
 	if (mixer != nullptr)
 		mixer_free(mixer);
-
-	delete prepared_replay_gain_filter;
-	delete prepared_other_replay_gain_filter;
-	delete prepared_filter;
 }
 
 void
diff --git a/src/output/Init.cxx b/src/output/Init.cxx
index 70bb960a3..9dbd14ef6 100644
--- a/src/output/Init.cxx
+++ b/src/output/Init.cxx
@@ -22,12 +22,13 @@
 #include "Registry.hxx"
 #include "Domain.hxx"
 #include "OutputAPI.hxx"
-#include "filter/FilterConfig.hxx"
 #include "AudioParser.hxx"
 #include "mixer/MixerList.hxx"
 #include "mixer/MixerType.hxx"
 #include "mixer/MixerControl.hxx"
 #include "mixer/plugins/SoftwareMixerPlugin.hxx"
+#include "filter/FilterConfig.hxx"
+#include "filter/FilterInternal.hxx"
 #include "filter/plugins/AutoConvertFilterPlugin.hxx"
 #include "filter/plugins/ConvertFilterPlugin.hxx"
 #include "filter/plugins/ReplayGainFilterPlugin.hxx"
diff --git a/src/output/Thread.cxx b/src/output/Thread.cxx
index fe2e42512..2ff81c8e3 100644
--- a/src/output/Thread.cxx
+++ b/src/output/Thread.cxx
@@ -146,8 +146,8 @@ AudioOutputControl::InternalOpen(const AudioFormat in_audio_format,
 	try {
 		try {
 			f = source.Open(in_audio_format, pipe,
-					output->prepared_replay_gain_filter,
-					output->prepared_other_replay_gain_filter,
+					output->prepared_replay_gain_filter.get(),
+					output->prepared_other_replay_gain_filter.get(),
 					*output->prepared_filter);
 		} catch (...) {
 			std::throw_with_nested(FormatRuntimeError("Failed to open filter for %s",
diff --git a/test/run_filter.cxx b/test/run_filter.cxx
index 2251cf1c4..bad10169e 100644
--- a/test/run_filter.cxx
+++ b/test/run_filter.cxx
@@ -48,7 +48,7 @@ mixer_set_volume(gcc_unused Mixer *mixer,
 {
 }
 
-static PreparedFilter *
+static std::unique_ptr<PreparedFilter>
 load_filter(const char *name)
 {
 	const auto *param = config_find_block(ConfigBlockOption::AUDIO_FILTER,
@@ -86,7 +86,7 @@ try {
 
 	/* initialize the filter */
 
-	std::unique_ptr<PreparedFilter> prepared_filter(load_filter(argv[2]));
+	auto prepared_filter = load_filter(argv[2]);
 	if (!prepared_filter)
 		return EXIT_FAILURE;