Filter/Internal: migrate from class Error to C++ exceptions

14 files changed, 142 insertions, 191 deletions

diff --git a/src/filter/FilterInternal.hxx b/src/filter/FilterInternal.hxx
index 2921314f5..6cf8c37cb 100644
--- a/src/filter/FilterInternal.hxx
+++ b/src/filter/FilterInternal.hxx
@@ -54,13 +54,15 @@ public:
 	/**
 	 * Filters a block of PCM data.
 	 *
+	 * Throws std::runtime_error on error.
+	 *
 	 * @param src the input buffer
 	 * @param error location to store the error occurring
 	 * @return the destination buffer on success (will be
 	 * invalidated by deleting this object or the next FilterPCM()
-	 * call), nullptr on error
+	 * call)
 	 */
-	virtual ConstBuffer<void> FilterPCM(ConstBuffer<void> src, Error &error) = 0;
+	virtual ConstBuffer<void> FilterPCM(ConstBuffer<void> src) = 0;
 };
 
 class PreparedFilter {
@@ -70,12 +72,13 @@ public:
 	/**
 	 * Opens the filter, preparing it for FilterPCM().
 	 *
+	 * Throws std::runtime_error on error.
+	 *
 	 * @param af the audio format of incoming data; the
 	 * plugin may modify the object to enforce another input
 	 * format
-	 * @param error location to store the error occurring
 	 */
-	virtual Filter *Open(AudioFormat &af, Error &error) = 0;
+	virtual Filter *Open(AudioFormat &af) = 0;
 };
 
 #endif
diff --git a/src/filter/Observer.cxx b/src/filter/Observer.cxx
index 310234e95..caad18254 100644
--- a/src/filter/Observer.cxx
+++ b/src/filter/Observer.cxx
@@ -51,7 +51,7 @@ public:
 
 	Filter *Get();
 
-	Filter *Open(AudioFormat &af, Error &error) override;
+	Filter *Open(AudioFormat &af) override;
 };
 
 class FilterObserver::Proxy final : public Filter {
@@ -73,9 +73,8 @@ public:
 		return filter;
 	}
 
-	ConstBuffer<void> FilterPCM(ConstBuffer<void> src,
-				    Error &error) override {
-		return filter->FilterPCM(src, error);
+	ConstBuffer<void> FilterPCM(ConstBuffer<void> src) override {
+		return filter->FilterPCM(src);
 	}
 };
 
@@ -88,14 +87,11 @@ FilterObserver::PreparedProxy::Get()
 }
 
 Filter *
-FilterObserver::PreparedProxy::Open(AudioFormat &af, Error &error)
+FilterObserver::PreparedProxy::Open(AudioFormat &af)
 {
 	assert(child == nullptr);
 
-	Filter *f = prepared_filter->Open(af, error);
-	if (f == nullptr)
-		return f;
-
+	Filter *f = prepared_filter->Open(af);
 	return child = new Proxy(*this, f);
 }
 
diff --git a/src/filter/plugins/AutoConvertFilterPlugin.cxx b/src/filter/plugins/AutoConvertFilterPlugin.cxx
index 6ee2aae03..ba2e2fa01 100644
--- a/src/filter/plugins/AutoConvertFilterPlugin.cxx
+++ b/src/filter/plugins/AutoConvertFilterPlugin.cxx
@@ -47,8 +47,7 @@ public:
 			  std::unique_ptr<Filter> &&_convert)
 		:filter(std::move(_filter)), convert(std::move(_convert)) {}
 
-	virtual ConstBuffer<void> FilterPCM(ConstBuffer<void> src,
-					    Error &error) override;
+	ConstBuffer<void> FilterPCM(ConstBuffer<void> src) override;
 };
 
 class PreparedAutoConvertFilter final : public PreparedFilter {
@@ -63,20 +62,18 @@ public:
 		delete filter;
 	}
 
-	virtual Filter *Open(AudioFormat &af, Error &error) override;
+	Filter *Open(AudioFormat &af) override;
 };
 
 Filter *
-PreparedAutoConvertFilter::Open(AudioFormat &in_audio_format, Error &error)
+PreparedAutoConvertFilter::Open(AudioFormat &in_audio_format)
 {
 	assert(in_audio_format.IsValid());
 
 	/* open the "real" filter */
 
 	AudioFormat child_audio_format = in_audio_format;
-	std::unique_ptr<Filter> new_filter(filter->Open(child_audio_format, error));
-	if (!new_filter)
-		return nullptr;
+	std::unique_ptr<Filter> new_filter(filter->Open(child_audio_format));
 
 	/* need to convert? */
 
@@ -85,10 +82,7 @@ PreparedAutoConvertFilter::Open(AudioFormat &in_audio_format, Error &error)
 		/* yes - create a convert_filter */
 
 		convert.reset(convert_filter_new(in_audio_format,
-						 child_audio_format,
-						 error));
-		if (!convert)
-			return nullptr;
+						 child_audio_format));
 	}
 
 	return new AutoConvertFilter(std::move(new_filter),
@@ -96,15 +90,15 @@ PreparedAutoConvertFilter::Open(AudioFormat &in_audio_format, Error &error)
 }
 
 ConstBuffer<void>
-AutoConvertFilter::FilterPCM(ConstBuffer<void> src, Error &error)
+AutoConvertFilter::FilterPCM(ConstBuffer<void> src)
 {
 	if (convert != nullptr) {
-		src = convert->FilterPCM(src, error);
+		src = convert->FilterPCM(src);
 		if (src.IsNull())
 			return nullptr;
 	}
 
-	return filter->FilterPCM(src, error);
+	return filter->FilterPCM(src);
 }
 
 PreparedFilter *
diff --git a/src/filter/plugins/ChainFilterPlugin.cxx b/src/filter/plugins/ChainFilterPlugin.cxx
index 4b79baf5b..fafba0250 100644
--- a/src/filter/plugins/ChainFilterPlugin.cxx
+++ b/src/filter/plugins/ChainFilterPlugin.cxx
@@ -23,9 +23,8 @@
 #include "filter/FilterInternal.hxx"
 #include "filter/FilterRegistry.hxx"
 #include "AudioFormat.hxx"
-#include "util/Error.hxx"
-#include "util/Domain.hxx"
 #include "util/ConstBuffer.hxx"
+#include "util/RuntimeError.hxx"
 
 #include <memory>
 #include <list>
@@ -62,8 +61,7 @@ public:
 	}
 
 	/* virtual methods from class Filter */
-	ConstBuffer<void> FilterPCM(ConstBuffer<void> src,
-					    Error &error) override;
+	ConstBuffer<void> FilterPCM(ConstBuffer<void> src) override;
 };
 
 class PreparedChainFilter final : public PreparedFilter {
@@ -80,8 +78,7 @@ class PreparedChainFilter final : public PreparedFilter {
 		Child(const Child &) = delete;
 		Child &operator=(const Child &) = delete;
 
-		Filter *Open(const AudioFormat &prev_audio_format,
-			     Error &error);
+		Filter *Open(const AudioFormat &prev_audio_format);
 	};
 
 	std::list<Child> children;
@@ -92,11 +89,9 @@ public:
 	}
 
 	/* virtual methods from class PreparedFilter */
-	Filter *Open(AudioFormat &af, Error &error) override;
+	Filter *Open(AudioFormat &af) override;
 };
 
-static constexpr Domain chain_filter_domain("chain_filter");
-
 static PreparedFilter *
 chain_filter_init(gcc_unused const ConfigBlock &block,
 		  gcc_unused Error &error)
@@ -105,39 +100,31 @@ chain_filter_init(gcc_unused const ConfigBlock &block,
 }
 
 Filter *
-PreparedChainFilter::Child::Open(const AudioFormat &prev_audio_format,
-				 Error &error)
+PreparedChainFilter::Child::Open(const AudioFormat &prev_audio_format)
 {
 	AudioFormat conv_audio_format = prev_audio_format;
-	Filter *new_filter = filter->Open(conv_audio_format, error);
-	if (new_filter == nullptr)
-		return nullptr;
+	Filter *new_filter = filter->Open(conv_audio_format);
 
 	if (conv_audio_format != prev_audio_format) {
 		delete new_filter;
 
 		struct audio_format_string s;
-		error.Format(chain_filter_domain,
-			     "Audio format not supported by filter '%s': %s",
-			     name,
-			     audio_format_to_string(prev_audio_format, &s));
-		return nullptr;
+		throw FormatRuntimeError("Audio format not supported by filter '%s': %s",
+					 name,
+					 audio_format_to_string(prev_audio_format, &s));
 	}
 
 	return new_filter;
 }
 
 Filter *
-PreparedChainFilter::Open(AudioFormat &in_audio_format, Error &error)
+PreparedChainFilter::Open(AudioFormat &in_audio_format)
 {
 	std::unique_ptr<ChainFilter> chain(new ChainFilter(in_audio_format));
 
 	for (auto &child : children) {
 		AudioFormat audio_format = chain->GetOutAudioFormat();
-		auto *filter = child.Open(audio_format, error);
-		if (filter == nullptr)
-			return nullptr;
-
+		auto *filter = child.Open(audio_format);
 		chain->Append(child.name, filter);
 	}
 
@@ -145,14 +132,12 @@ PreparedChainFilter::Open(AudioFormat &in_audio_format, Error &error)
 }
 
 ConstBuffer<void>
-ChainFilter::FilterPCM(ConstBuffer<void> src, Error &error)
+ChainFilter::FilterPCM(ConstBuffer<void> src)
 {
 	for (auto &child : children) {
 		/* feed the output of the previous filter as input
 		   into the current one */
-		src = child.filter->FilterPCM(src, error);
-		if (src.IsNull())
-			return nullptr;
+		src = child.filter->FilterPCM(src);
 	}
 
 	/* return the output of the last filter */
diff --git a/src/filter/plugins/ConvertFilterPlugin.cxx b/src/filter/plugins/ConvertFilterPlugin.cxx
index 51022843d..fb8e684b6 100644
--- a/src/filter/plugins/ConvertFilterPlugin.cxx
+++ b/src/filter/plugins/ConvertFilterPlugin.cxx
@@ -25,9 +25,13 @@
 #include "pcm/PcmConvert.hxx"
 #include "util/Manual.hxx"
 #include "util/ConstBuffer.hxx"
+#include "util/Error.hxx"
 #include "AudioFormat.hxx"
 #include "poison.h"
 
+#include <stdexcept>
+#include <memory>
+
 #include <assert.h>
 
 class ConvertFilter final : public Filter {
@@ -47,17 +51,16 @@ public:
 	ConvertFilter(const AudioFormat &audio_format);
 	~ConvertFilter();
 
-	bool Set(const AudioFormat &_out_audio_format, Error &error);
+	void Set(const AudioFormat &_out_audio_format);
 
-	virtual ConstBuffer<void> FilterPCM(ConstBuffer<void> src,
-					    Error &error) override;
+	ConstBuffer<void> FilterPCM(ConstBuffer<void> src) override;
 };
 
 class PreparedConvertFilter final : public PreparedFilter {
 public:
-	bool Set(const AudioFormat &_out_audio_format, Error &error);
+	void Set(const AudioFormat &_out_audio_format);
 
-	Filter *Open(AudioFormat &af, Error &error) override;
+	Filter *Open(AudioFormat &af) override;
 };
 
 static PreparedFilter *
@@ -67,15 +70,15 @@ convert_filter_init(gcc_unused const ConfigBlock &block,
 	return new PreparedConvertFilter();
 }
 
-bool
-ConvertFilter::Set(const AudioFormat &_out_audio_format, Error &error)
+void
+ConvertFilter::Set(const AudioFormat &_out_audio_format)
 {
 	assert(in_audio_format.IsValid());
 	assert(_out_audio_format.IsValid());
 
 	if (_out_audio_format == out_audio_format)
 		/* no change */
-		return true;
+		return;
 
 	if (out_audio_format != in_audio_format) {
 		out_audio_format = in_audio_format;
@@ -84,13 +87,13 @@ ConvertFilter::Set(const AudioFormat &_out_audio_format, Error &error)
 
 	if (_out_audio_format == in_audio_format)
 		/* optimized special case: no-op */
-		return true;
+		return;
 
+	Error error;
 	if (!state.Open(in_audio_format, _out_audio_format, error))
-		return false;
+		throw std::runtime_error(error.GetMessage());
 
 	out_audio_format = _out_audio_format;
-	return true;
 }
 
 ConvertFilter::ConvertFilter(const AudioFormat &audio_format)
@@ -99,7 +102,7 @@ ConvertFilter::ConvertFilter(const AudioFormat &audio_format)
 }
 
 Filter *
-PreparedConvertFilter::Open(AudioFormat &audio_format, gcc_unused Error &error)
+PreparedConvertFilter::Open(AudioFormat &audio_format)
 {
 	assert(audio_format.IsValid());
 
@@ -115,7 +118,7 @@ ConvertFilter::~ConvertFilter()
 }
 
 ConstBuffer<void>
-ConvertFilter::FilterPCM(ConstBuffer<void> src, Error &error)
+ConvertFilter::FilterPCM(ConstBuffer<void> src)
 {
 	assert(in_audio_format.IsValid());
 
@@ -123,7 +126,12 @@ ConvertFilter::FilterPCM(ConstBuffer<void> src, Error &error)
 		/* optimized special case: no-op */
 		return src;
 
-	return state.Convert(src, error);
+	Error error;
+	auto result = state.Convert(src, error);
+	if (result.IsNull())
+		throw std::runtime_error(error.GetMessage());
+
+	return result;
 }
 
 const struct filter_plugin convert_filter_plugin = {
@@ -133,23 +141,17 @@ const struct filter_plugin convert_filter_plugin = {
 
 Filter *
 convert_filter_new(const AudioFormat in_audio_format,
-		   const AudioFormat out_audio_format,
-		   Error &error)
+		   const AudioFormat out_audio_format)
 {
-	auto *filter = new ConvertFilter(in_audio_format);
-	if (!filter->Set(out_audio_format, error)) {
-		delete filter;
-		return nullptr;
-	}
-
-	return filter;
+	std::unique_ptr<ConvertFilter> filter(new ConvertFilter(in_audio_format));
+	filter->Set(out_audio_format);
+	return filter.release();
 }
 
-bool
-convert_filter_set(Filter *_filter, AudioFormat out_audio_format,
-		   Error &error)
+void
+convert_filter_set(Filter *_filter, AudioFormat out_audio_format)
 {
 	ConvertFilter *filter = (ConvertFilter *)_filter;
 
-	return filter->Set(out_audio_format, error);
+	filter->Set(out_audio_format);
 }
diff --git a/src/filter/plugins/ConvertFilterPlugin.hxx b/src/filter/plugins/ConvertFilterPlugin.hxx
index 6bdd5ef1b..9d7890574 100644
--- a/src/filter/plugins/ConvertFilterPlugin.hxx
+++ b/src/filter/plugins/ConvertFilterPlugin.hxx
@@ -26,17 +26,17 @@ struct AudioFormat;
 
 Filter *
 convert_filter_new(AudioFormat in_audio_format,
-		   AudioFormat out_audio_format,
-		   Error &error);
+		   AudioFormat out_audio_format);
 
 /**
  * Sets the output audio format for the specified filter.  You must
  * call this after the filter has been opened.  Since this audio
  * format switch is a violation of the filter API, this filter must be
  * the last in a chain.
+ *
+ * Throws std::runtime_error on error.
  */
-bool
-convert_filter_set(Filter *filter, AudioFormat out_audio_format,
-		   Error &error);
+void
+convert_filter_set(Filter *filter, AudioFormat out_audio_format);
 
 #endif
diff --git a/src/filter/plugins/NormalizeFilterPlugin.cxx b/src/filter/plugins/NormalizeFilterPlugin.cxx
index e83b6553d..4211b8ced 100644
--- a/src/filter/plugins/NormalizeFilterPlugin.cxx
+++ b/src/filter/plugins/NormalizeFilterPlugin.cxx
@@ -43,14 +43,13 @@ public:
 	}
 
 	/* virtual methods from class Filter */
-	ConstBuffer<void> FilterPCM(ConstBuffer<void> src,
-				    Error &error) override;
+	ConstBuffer<void> FilterPCM(ConstBuffer<void> src) override;
 };
 
 class PreparedNormalizeFilter final : public PreparedFilter {
 public:
 	/* virtual methods from class PreparedFilter */
-	Filter *Open(AudioFormat &af, Error &error) override;
+	Filter *Open(AudioFormat &af) override;
 };
 
 static PreparedFilter *
@@ -61,7 +60,7 @@ normalize_filter_init(gcc_unused const ConfigBlock &block,
 }
 
 Filter *
-PreparedNormalizeFilter::Open(AudioFormat &audio_format, gcc_unused Error &error)
+PreparedNormalizeFilter::Open(AudioFormat &audio_format)
 {
 	audio_format.format = SampleFormat::S16;
 
@@ -69,7 +68,7 @@ PreparedNormalizeFilter::Open(AudioFormat &audio_format, gcc_unused Error &error
 }
 
 ConstBuffer<void>
-NormalizeFilter::FilterPCM(ConstBuffer<void> src, gcc_unused Error &error)
+NormalizeFilter::FilterPCM(ConstBuffer<void> src)
 {
 	int16_t *dest = (int16_t *)buffer.Get(src.size);
 	memcpy(dest, src.data, src.size);
diff --git a/src/filter/plugins/NullFilterPlugin.cxx b/src/filter/plugins/NullFilterPlugin.cxx
index fc43bb7d1..47a7bb555 100644
--- a/src/filter/plugins/NullFilterPlugin.cxx
+++ b/src/filter/plugins/NullFilterPlugin.cxx
@@ -36,16 +36,14 @@ class NullFilter final : public Filter {
 public:
 	explicit NullFilter(const AudioFormat &af):Filter(af) {}
 
-	virtual ConstBuffer<void> FilterPCM(ConstBuffer<void> src,
-					    gcc_unused Error &error) override {
+	virtual ConstBuffer<void> FilterPCM(ConstBuffer<void> src) override {
 		return src;
 	}
 };
 
 class PreparedNullFilter final : public PreparedFilter {
 public:
-	virtual Filter *Open(AudioFormat &af,
-			     gcc_unused Error &error) override {
+	virtual Filter *Open(AudioFormat &af) override {
 		return new NullFilter(af);
 	}
 };
diff --git a/src/filter/plugins/ReplayGainFilterPlugin.cxx b/src/filter/plugins/ReplayGainFilterPlugin.cxx
index 49b7674c4..1c36a17c7 100644
--- a/src/filter/plugins/ReplayGainFilterPlugin.cxx
+++ b/src/filter/plugins/ReplayGainFilterPlugin.cxx
@@ -32,6 +32,8 @@
 #include "util/Domain.hxx"
 #include "Log.hxx"
 
+#include <stdexcept>
+
 #include <assert.h>
 
 static constexpr Domain replay_gain_domain("replay_gain");
@@ -73,10 +75,10 @@ public:
 		:Filter(audio_format),
 		 mixer(_mixer), base(_base), mode(REPLAY_GAIN_OFF) {
 		info.Clear();
-	}
 
-	bool Open(Error &error) {
-		return pv.Open(out_audio_format.format, error);
+		Error error;
+		if (!pv.Open(out_audio_format.format, error))
+			throw std::runtime_error(error.GetMessage());
 	}
 
 	void SetInfo(const ReplayGainInfo *_info) {
@@ -108,8 +110,7 @@ public:
 	void Update();
 
 	/* virtual methods from class Filter */
-	ConstBuffer<void> FilterPCM(ConstBuffer<void> src,
-				    Error &error) override;
+	ConstBuffer<void> FilterPCM(ConstBuffer<void> src) override;
 };
 
 class PreparedReplayGainFilter final : public PreparedFilter {
@@ -134,7 +135,7 @@ public:
 	}
 
 	/* virtual methods from class Filter */
-	Filter *Open(AudioFormat &af, Error &error) override;
+	Filter *Open(AudioFormat &af) override;
 };
 
 void
@@ -174,19 +175,13 @@ replay_gain_filter_init(gcc_unused const ConfigBlock &block,
 }
 
 Filter *
-PreparedReplayGainFilter::Open(AudioFormat &af, gcc_unused Error &error)
+PreparedReplayGainFilter::Open(AudioFormat &af)
 {
-	auto *filter = new ReplayGainFilter(af, mixer, base);
-	if (!filter->Open(error)) {
-		delete filter;
-		return nullptr;
-	}
-
-	return filter;
+	return new ReplayGainFilter(af, mixer, base);
 }
 
 ConstBuffer<void>
-ReplayGainFilter::FilterPCM(ConstBuffer<void> src, gcc_unused Error &error)
+ReplayGainFilter::FilterPCM(ConstBuffer<void> src)
 {
 	return mixer != nullptr
 		? src
diff --git a/src/filter/plugins/RouteFilterPlugin.cxx b/src/filter/plugins/RouteFilterPlugin.cxx
index b04362c90..f08bf84bc 100644
--- a/src/filter/plugins/RouteFilterPlugin.cxx
+++ b/src/filter/plugins/RouteFilterPlugin.cxx
@@ -96,8 +96,7 @@ public:
 		    const std::array<int8_t, MAX_CHANNELS> &_sources);
 
 	/* virtual methods from class Filter */
-	ConstBuffer<void> FilterPCM(ConstBuffer<void> src,
-				    Error &error) override;
+	ConstBuffer<void> FilterPCM(ConstBuffer<void> src) override;
 };
 
 class PreparedRouteFilter final : public PreparedFilter {
@@ -136,7 +135,7 @@ public:
 	bool Configure(const ConfigBlock &block, Error &error);
 
 	/* virtual methods from class PreparedFilter */
-	Filter *Open(AudioFormat &af, Error &error) override;
+	Filter *Open(AudioFormat &af) override;
 };
 
 bool
@@ -243,13 +242,13 @@ RouteFilter::RouteFilter(const AudioFormat &audio_format,
 }
 
 Filter *
-PreparedRouteFilter::Open(AudioFormat &audio_format, gcc_unused Error &error)
+PreparedRouteFilter::Open(AudioFormat &audio_format)
 {
 	return new RouteFilter(audio_format, min_output_channels, sources);
 }
 
 ConstBuffer<void>
-RouteFilter::FilterPCM(ConstBuffer<void> src, gcc_unused Error &error)
+RouteFilter::FilterPCM(ConstBuffer<void> src)
 {
 	size_t number_of_frames = src.size / input_frame_size;
 
diff --git a/src/filter/plugins/VolumeFilterPlugin.cxx b/src/filter/plugins/VolumeFilterPlugin.cxx
index 7e7fa2a4a..530839030 100644
--- a/src/filter/plugins/VolumeFilterPlugin.cxx
+++ b/src/filter/plugins/VolumeFilterPlugin.cxx
@@ -25,16 +25,19 @@
 #include "pcm/Volume.hxx"
 #include "AudioFormat.hxx"
 #include "util/ConstBuffer.hxx"
+#include "util/Error.hxx"
+
+#include <stdexcept>
 
 class VolumeFilter final : public Filter {
 	PcmVolume pv;
 
 public:
 	explicit VolumeFilter(const AudioFormat &audio_format)
-		:Filter(audio_format) {}
-
-	bool Open(Error &error) {
-		return pv.Open(out_audio_format.format, error);
+		:Filter(audio_format) {
+		Error error;
+		if (!pv.Open(out_audio_format.format, error))
+			throw std::runtime_error(error.GetMessage());
 	}
 
 	unsigned GetVolume() const {
@@ -46,8 +49,7 @@ public:
 	}
 
 	/* virtual methods from class Filter */
-	ConstBuffer<void> FilterPCM(ConstBuffer<void> src,
-				    Error &error) override;
+	ConstBuffer<void> FilterPCM(ConstBuffer<void> src) override;
 };
 
 class PreparedVolumeFilter final : public PreparedFilter {
@@ -55,7 +57,7 @@ class PreparedVolumeFilter final : public PreparedFilter {
 
 public:
 	/* virtual methods from class Filter */
-	Filter *Open(AudioFormat &af, Error &error) override;
+	Filter *Open(AudioFormat &af) override;
 };
 
 static PreparedFilter *
@@ -66,19 +68,13 @@ volume_filter_init(gcc_unused const ConfigBlock &block,
 }
 
 Filter *
-PreparedVolumeFilter::Open(AudioFormat &audio_format, Error &error)
+PreparedVolumeFilter::Open(AudioFormat &audio_format)
 {
-	auto *filter = new VolumeFilter(audio_format);
-	if (!filter->Open(error)) {
-		delete filter;
-		return nullptr;
-	}
-
-	return filter;
+	return new VolumeFilter(audio_format);
 }
 
 ConstBuffer<void>
-VolumeFilter::FilterPCM(ConstBuffer<void> src, gcc_unused Error &error)
+VolumeFilter::FilterPCM(ConstBuffer<void> src)
 {
 	return pv.Apply(src);
 }
diff --git a/src/output/Internal.hxx b/src/output/Internal.hxx
index d0a8b3440..d9958f03f 100644
--- a/src/output/Internal.hxx
+++ b/src/output/Internal.hxx
@@ -404,7 +404,10 @@ private:
 	 */
 	void CloseOutput(bool drain);
 
-	AudioFormat OpenFilter(AudioFormat &format, Error &error_r);
+	/**
+	 * Throws std::runtime_error on error.
+	 */
+	AudioFormat OpenFilter(AudioFormat &format);
 
 	/**
 	 * Mutex must not be locked.
diff --git a/src/output/OutputThread.cxx b/src/output/OutputThread.cxx
index 6950f7a21..24819feb8 100644
--- a/src/output/OutputThread.cxx
+++ b/src/output/OutputThread.cxx
@@ -93,38 +93,28 @@ AudioOutput::Disable()
 }
 
 inline AudioFormat
-AudioOutput::OpenFilter(AudioFormat &format, Error &error_r)
-{
+AudioOutput::OpenFilter(AudioFormat &format)
+try {
 	assert(format.IsValid());
 
 	/* the replay_gain filter cannot fail here */
-	if (prepared_replay_gain_filter != nullptr) {
+	if (prepared_replay_gain_filter != nullptr)
 		replay_gain_filter_instance =
-			prepared_replay_gain_filter->Open(format, error_r);
-		if (replay_gain_filter_instance == nullptr)
-			return AudioFormat::Undefined();
-	}
+			prepared_replay_gain_filter->Open(format);
 
-	if (prepared_other_replay_gain_filter != nullptr) {
+	if (prepared_other_replay_gain_filter != nullptr)
 		other_replay_gain_filter_instance =
-			prepared_other_replay_gain_filter->Open(format, error_r);
-		if (other_replay_gain_filter_instance == nullptr) {
-			delete replay_gain_filter_instance;
-			return AudioFormat::Undefined();
-		}
-	}
+			prepared_other_replay_gain_filter->Open(format);
 
-	filter_instance = prepared_filter->Open(format, error_r);
-	if (filter_instance == nullptr) {
-		delete other_replay_gain_filter_instance;
-		delete replay_gain_filter_instance;
-		return AudioFormat::Undefined();
-	}
+	filter_instance = prepared_filter->Open(format);
 
 	if (mixer != nullptr && mixer->IsPlugin(software_mixer_plugin))
 		software_mixer_set_filter(*mixer, volume_filter.Get());
 
 	return filter_instance->GetOutAudioFormat();
+} catch (...) {
+	CloseFilter();
+	throw;
 }
 
 void
@@ -165,10 +155,11 @@ AudioOutput::Open()
 
 	/* open the filter */
 
-	const AudioFormat filter_audio_format =
-		OpenFilter(in_audio_format, error);
-	if (!filter_audio_format.IsDefined()) {
-		FormatError(error, "Failed to open filter for \"%s\" [%s]",
+	AudioFormat filter_audio_format;
+	try {
+		filter_audio_format = OpenFilter(in_audio_format);
+	} catch (const std::runtime_error &e) {
+		FormatError(e, "Failed to open filter for \"%s\" [%s]",
 			    name, plugin.name);
 
 		fail_timer.Update();
@@ -202,9 +193,10 @@ AudioOutput::Open()
 		return;
 	}
 
-	if (!convert_filter_set(convert_filter.Get(), out_audio_format,
-				error)) {
-		FormatError(error, "Failed to convert for \"%s\" [%s]",
+	try {
+		convert_filter_set(convert_filter.Get(), out_audio_format);
+	} catch (const std::runtime_error &e) {
+		FormatError(e, "Failed to convert for \"%s\" [%s]",
 			    name, plugin.name);
 
 		mutex.unlock();
@@ -295,12 +287,12 @@ AudioOutput::ReopenFilter()
 	CloseFilter();
 	mutex.lock();
 
-	const AudioFormat filter_audio_format =
-		OpenFilter(in_audio_format, error);
-	if (!filter_audio_format.IsDefined() ||
-	    !convert_filter_set(convert_filter.Get(), out_audio_format,
-				error)) {
-		FormatError(error,
+	AudioFormat filter_audio_format;
+	try {
+		filter_audio_format = OpenFilter(in_audio_format);
+		convert_filter_set(convert_filter.Get(), out_audio_format);
+	} catch (const std::runtime_error &e) {
+		FormatError(e,
 			    "Failed to open filter for \"%s\" [%s]",
 			    name, plugin.name);
 
@@ -383,11 +375,13 @@ ao_chunk_data(AudioOutput *ao, const MusicChunk *chunk,
 			*replay_gain_serial_p = chunk->replay_gain_serial;
 		}
 
-		Error error;
-		data = replay_gain_filter->FilterPCM(data, error);
-		if (data.IsNull())
-			FormatError(error, "\"%s\" [%s] failed to filter",
+		try {
+			data = replay_gain_filter->FilterPCM(data);
+		} catch (const std::runtime_error &e) {
+			FormatError(e, "\"%s\" [%s] failed to filter",
 				    ao->name, ao->plugin.name);
+			return nullptr;
+		}
 	}
 
 	return data;
@@ -449,15 +443,13 @@ ao_filter_chunk(AudioOutput *ao, const MusicChunk *chunk)
 
 	/* apply filter chain */
 
-	Error error;
-	data = ao->filter_instance->FilterPCM(data, error);
-	if (data.IsNull()) {
-		FormatError(error, "\"%s\" [%s] failed to filter",
+	try {
+		return ao->filter_instance->FilterPCM(data);
+	} catch (const std::runtime_error &e) {
+		FormatError(e, "\"%s\" [%s] failed to filter",
 			    ao->name, ao->plugin.name);
 		return nullptr;
 	}
-
-	return data;
 }
 
 inline bool
diff --git a/test/run_filter.cxx b/test/run_filter.cxx
index 0fa414e39..58f235956 100644
--- a/test/run_filter.cxx
+++ b/test/run_filter.cxx
@@ -105,13 +105,7 @@ try {
 
 	/* open the filter */
 
-	Error error;
-	std::unique_ptr<Filter> filter(prepared_filter->Open(audio_format,
-							     error));
-	if (!filter) {
-		LogError(error, "Failed to open filter");
-		return EXIT_FAILURE;
-	}
+	std::unique_ptr<Filter> filter(prepared_filter->Open(audio_format));
 
 	const AudioFormat out_audio_format = filter->GetOutAudioFormat();
 
@@ -127,12 +121,7 @@ try {
 		if (nbytes <= 0)
 			break;
 
-		auto dest = filter->FilterPCM({(const void *)buffer, (size_t)nbytes},
-					      error);
-		if (dest.IsNull()) {
-			LogError(error, "filter/Filter failed");
-			return EXIT_FAILURE;
-		}
+		auto dest = filter->FilterPCM({(const void *)buffer, (size_t)nbytes});
 
 		nbytes = write(1, dest.data, dest.size);
 		if (nbytes < 0) {
@@ -147,7 +136,7 @@ try {
 	config_global_finish();
 
 	return EXIT_SUCCESS;
- } catch (const std::exception &e) {
+} catch (const std::exception &e) {
 	LogError(e);
 	return EXIT_FAILURE;
- }
+}