filter/Internal: rename struct AudioOutput to FilteredAudioOutput

Prepare to add an abstract class AudioOutput, to be implemented by
plugins, to get rid of the C-style vtable.

43 files changed, 138 insertions, 138 deletions

diff --git a/src/mixer/MixerControl.cxx b/src/mixer/MixerControl.cxx
index 3c6f86236..117fdfbcd 100644
--- a/src/mixer/MixerControl.cxx
+++ b/src/mixer/MixerControl.cxx
@@ -25,7 +25,7 @@
 
 Mixer *
 mixer_new(EventLoop &event_loop,
-	  const MixerPlugin &plugin, AudioOutput &ao,
+	  const MixerPlugin &plugin, FilteredAudioOutput &ao,
 	  MixerListener &listener,
 	  const ConfigBlock &block)
 {
diff --git a/src/mixer/MixerControl.hxx b/src/mixer/MixerControl.hxx
index e71592edb..bc4e54801 100644
--- a/src/mixer/MixerControl.hxx
+++ b/src/mixer/MixerControl.hxx
@@ -27,7 +27,7 @@
 
 class Mixer;
 class EventLoop;
-struct AudioOutput;
+struct FilteredAudioOutput;
 struct MixerPlugin;
 class MixerListener;
 struct ConfigBlock;
@@ -36,7 +36,8 @@ struct ConfigBlock;
  * Throws std::runtime_error on error.
  */
 Mixer *
-mixer_new(EventLoop &event_loop, const MixerPlugin &plugin, AudioOutput &ao,
+mixer_new(EventLoop &event_loop, const MixerPlugin &plugin,
+	  FilteredAudioOutput &ao,
 	  MixerListener &listener,
 	  const ConfigBlock &block);
 
diff --git a/src/mixer/MixerPlugin.hxx b/src/mixer/MixerPlugin.hxx
index a5693ddd2..d9cded5f5 100644
--- a/src/mixer/MixerPlugin.hxx
+++ b/src/mixer/MixerPlugin.hxx
@@ -28,7 +28,7 @@
 #define MPD_MIXER_PLUGIN_HXX
 
 struct ConfigBlock;
-struct AudioOutput;
+struct FilteredAudioOutput;
 class Mixer;
 class MixerListener;
 class EventLoop;
@@ -39,11 +39,11 @@ struct MixerPlugin {
 	 *
 	 * Throws std::runtime_error on error.
 	 *
-	 * @param ao the associated AudioOutput
+	 * @param ao the associated #AudioOutput
 	 * @param param the configuration section
 	 * @return a mixer object
 	 */
-	Mixer *(*init)(EventLoop &event_loop, AudioOutput &ao,
+	Mixer *(*init)(EventLoop &event_loop, FilteredAudioOutput &ao,
 		       MixerListener &listener,
 		       const ConfigBlock &block);
 
diff --git a/src/mixer/plugins/AlsaMixerPlugin.cxx b/src/mixer/plugins/AlsaMixerPlugin.cxx
index 49ec15c3b..76ad79d92 100644
--- a/src/mixer/plugins/AlsaMixerPlugin.cxx
+++ b/src/mixer/plugins/AlsaMixerPlugin.cxx
@@ -173,7 +173,7 @@ AlsaMixer::Configure(const ConfigBlock &block)
 }
 
 static Mixer *
-alsa_mixer_init(EventLoop &event_loop, gcc_unused AudioOutput &ao,
+alsa_mixer_init(EventLoop &event_loop, gcc_unused FilteredAudioOutput &ao,
 		MixerListener &listener,
 		const ConfigBlock &block)
 {
diff --git a/src/mixer/plugins/HaikuMixerPlugin.cxx b/src/mixer/plugins/HaikuMixerPlugin.cxx
index f0b50a91c..23f096430 100644
--- a/src/mixer/plugins/HaikuMixerPlugin.cxx
+++ b/src/mixer/plugins/HaikuMixerPlugin.cxx
@@ -48,7 +48,7 @@ public:
 };
 
 static Mixer *
-haiku_mixer_init(gcc_unused EventLoop &event_loop, AudioOutput &ao,
+haiku_mixer_init(gcc_unused EventLoop &event_loop, FilteredAudioOutput &ao,
 		MixerListener &listener,
 		gcc_unused const ConfigBlock &block)
 {
diff --git a/src/mixer/plugins/NullMixerPlugin.cxx b/src/mixer/plugins/NullMixerPlugin.cxx
index 66b6409b1..bacfe86c2 100644
--- a/src/mixer/plugins/NullMixerPlugin.cxx
+++ b/src/mixer/plugins/NullMixerPlugin.cxx
@@ -51,7 +51,7 @@ public:
 
 static Mixer *
 null_mixer_init(gcc_unused EventLoop &event_loop,
-		gcc_unused AudioOutput &ao,
+		gcc_unused FilteredAudioOutput &ao,
 		MixerListener &listener,
 		gcc_unused const ConfigBlock &block)
 {
diff --git a/src/mixer/plugins/OssMixerPlugin.cxx b/src/mixer/plugins/OssMixerPlugin.cxx
index 72cb72a47..23135c477 100644
--- a/src/mixer/plugins/OssMixerPlugin.cxx
+++ b/src/mixer/plugins/OssMixerPlugin.cxx
@@ -97,7 +97,8 @@ OssMixer::Configure(const ConfigBlock &block)
 }
 
 static Mixer *
-oss_mixer_init(gcc_unused EventLoop &event_loop, gcc_unused AudioOutput &ao,
+oss_mixer_init(gcc_unused EventLoop &event_loop,
+	       gcc_unused FilteredAudioOutput &ao,
 	       MixerListener &listener,
 	       const ConfigBlock &block)
 {
diff --git a/src/mixer/plugins/PulseMixerPlugin.cxx b/src/mixer/plugins/PulseMixerPlugin.cxx
index 5919e0ee6..670c4053e 100644
--- a/src/mixer/plugins/PulseMixerPlugin.cxx
+++ b/src/mixer/plugins/PulseMixerPlugin.cxx
@@ -161,7 +161,7 @@ pulse_mixer_on_change(PulseMixer &pm,
 }
 
 static Mixer *
-pulse_mixer_init(gcc_unused EventLoop &event_loop, AudioOutput &ao,
+pulse_mixer_init(gcc_unused EventLoop &event_loop, FilteredAudioOutput &ao,
 		 MixerListener &listener,
 		 gcc_unused const ConfigBlock &block)
 {
diff --git a/src/mixer/plugins/RoarMixerPlugin.cxx b/src/mixer/plugins/RoarMixerPlugin.cxx
index d3df5f910..e94c6ec78 100644
--- a/src/mixer/plugins/RoarMixerPlugin.cxx
+++ b/src/mixer/plugins/RoarMixerPlugin.cxx
@@ -45,7 +45,7 @@ public:
 };
 
 static Mixer *
-roar_mixer_init(gcc_unused EventLoop &event_loop, AudioOutput &ao,
+roar_mixer_init(gcc_unused EventLoop &event_loop, FilteredAudioOutput &ao,
 		MixerListener &listener,
 		gcc_unused const ConfigBlock &block)
 {
diff --git a/src/mixer/plugins/SoftwareMixerPlugin.cxx b/src/mixer/plugins/SoftwareMixerPlugin.cxx
index 0a1684b47..df54a1ae9 100644
--- a/src/mixer/plugins/SoftwareMixerPlugin.cxx
+++ b/src/mixer/plugins/SoftwareMixerPlugin.cxx
@@ -58,7 +58,7 @@ public:
 
 static Mixer *
 software_mixer_init(gcc_unused EventLoop &event_loop,
-		    gcc_unused AudioOutput &ao,
+		    gcc_unused FilteredAudioOutput &ao,
 		    MixerListener &listener,
 		    gcc_unused const ConfigBlock &block)
 {
diff --git a/src/mixer/plugins/WinmmMixerPlugin.cxx b/src/mixer/plugins/WinmmMixerPlugin.cxx
index bfbbe9d3d..eb00ddf66 100644
--- a/src/mixer/plugins/WinmmMixerPlugin.cxx
+++ b/src/mixer/plugins/WinmmMixerPlugin.cxx
@@ -64,7 +64,7 @@ winmm_volume_encode(int volume)
 }
 
 static Mixer *
-winmm_mixer_init(gcc_unused EventLoop &event_loop, AudioOutput &ao,
+winmm_mixer_init(gcc_unused EventLoop &event_loop, FilteredAudioOutput &ao,
 		 MixerListener &listener,
 		 gcc_unused const ConfigBlock &block)
 {
diff --git a/src/output/Control.cxx b/src/output/Control.cxx
index 73c8db654..c15d22467 100644
--- a/src/output/Control.cxx
+++ b/src/output/Control.cxx
@@ -38,7 +38,7 @@ static constexpr PeriodClock::Duration REOPEN_AFTER = std::chrono::seconds(10);
 
 struct notify audio_output_client_notify;
 
-AudioOutputControl::AudioOutputControl(AudioOutput *_output,
+AudioOutputControl::AudioOutputControl(FilteredAudioOutput *_output,
 				       AudioOutputClient &_client)
 	:output(_output), client(_client),
 	 thread(BIND_THIS_METHOD(Task))
diff --git a/src/output/Control.hxx b/src/output/Control.hxx
index 5e6dc956a..46bad6898 100644
--- a/src/output/Control.hxx
+++ b/src/output/Control.hxx
@@ -38,7 +38,7 @@
 #include <stdint.h>
 
 enum class ReplayGainMode : uint8_t;
-struct AudioOutput;
+struct FilteredAudioOutput;
 struct MusicChunk;
 struct ConfigBlock;
 class MusicPipe;
@@ -50,7 +50,7 @@ class AudioOutputClient;
  * Controller for an #AudioOutput and its output thread.
  */
 class AudioOutputControl {
-	AudioOutput *output;
+	FilteredAudioOutput *output;
 
 	/**
 	 * The PlayerControl object which "owns" this output.  This
@@ -209,7 +209,8 @@ public:
 	 */
 	mutable Mutex mutex;
 
-	AudioOutputControl(AudioOutput *_output, AudioOutputClient &_client);
+	AudioOutputControl(FilteredAudioOutput *_output,
+			   AudioOutputClient &_client);
 
 #ifndef NDEBUG
 	~AudioOutputControl() {
@@ -303,16 +304,14 @@ public:
 	void CommandAsync(Command cmd) noexcept;
 
 	/**
-	 * Sends a command to the #AudioOutput object and waits for
-	 * completion.
+	 * Sends a command to the object and waits for completion.
 	 *
 	 * Caller must lock the mutex.
 	 */
 	void CommandWait(Command cmd) noexcept;
 
 	/**
-	 * Lock the #AudioOutput object and execute the command
-	 * synchronously.
+	 * Lock the object and execute the command synchronously.
 	 */
 	void LockCommandWait(Command cmd) noexcept;
 
diff --git a/src/output/Finish.cxx b/src/output/Finish.cxx
index dfa7df7f6..c8d372fa0 100644
--- a/src/output/Finish.cxx
+++ b/src/output/Finish.cxx
@@ -23,7 +23,7 @@
 #include "mixer/MixerControl.hxx"
 #include "filter/FilterInternal.hxx"
 
-AudioOutput::~AudioOutput()
+FilteredAudioOutput::~FilteredAudioOutput()
 {
 	if (mixer != nullptr)
 		mixer_free(mixer);
@@ -34,14 +34,14 @@ AudioOutput::~AudioOutput()
 }
 
 void
-AudioOutput::BeginDestroy() noexcept
+FilteredAudioOutput::BeginDestroy() noexcept
 {
 	if (mixer != nullptr)
 		mixer_auto_close(mixer);
 }
 
 void
-AudioOutput::FinishDestroy() noexcept
+FilteredAudioOutput::FinishDestroy() noexcept
 {
 	ao_plugin_finish(this);
 }
diff --git a/src/output/Init.cxx b/src/output/Init.cxx
index 29ee3d530..159c1d63b 100644
--- a/src/output/Init.cxx
+++ b/src/output/Init.cxx
@@ -50,8 +50,8 @@
 #define AUDIO_OUTPUT_FORMAT	"format"
 #define AUDIO_FILTERS		"filters"
 
-AudioOutput::AudioOutput(const AudioOutputPlugin &_plugin,
-			 const ConfigBlock &block)
+FilteredAudioOutput::FilteredAudioOutput(const AudioOutputPlugin &_plugin,
+					 const ConfigBlock &block)
 	:plugin(_plugin)
 {
 	assert(plugin.finish != nullptr);
@@ -108,7 +108,7 @@ audio_output_mixer_type(const ConfigBlock &block) noexcept
 }
 
 static Mixer *
-audio_output_load_mixer(EventLoop &event_loop, AudioOutput &ao,
+audio_output_load_mixer(EventLoop &event_loop, FilteredAudioOutput &ao,
 			const ConfigBlock &block,
 			const MixerPlugin *plugin,
 			PreparedFilter &filter_chain,
@@ -148,7 +148,7 @@ audio_output_load_mixer(EventLoop &event_loop, AudioOutput &ao,
 }
 
 void
-AudioOutput::Configure(const ConfigBlock &block)
+FilteredAudioOutput::Configure(const ConfigBlock &block)
 {
 	if (!block.IsNull()) {
 		name = block.GetBlockValue(AUDIO_OUTPUT_NAME);
@@ -192,10 +192,10 @@ AudioOutput::Configure(const ConfigBlock &block)
 }
 
 inline void
-AudioOutput::Setup(EventLoop &event_loop,
-		   const ReplayGainConfig &replay_gain_config,
-		   MixerListener &mixer_listener,
-		   const ConfigBlock &block)
+FilteredAudioOutput::Setup(EventLoop &event_loop,
+			   const ReplayGainConfig &replay_gain_config,
+			   MixerListener &mixer_listener,
+			   const ConfigBlock &block)
 {
 
 	/* create the replay_gain filter */
@@ -249,7 +249,7 @@ AudioOutput::Setup(EventLoop &event_loop,
 			    convert_filter.Set(convert_filter_prepare()));
 }
 
-AudioOutput *
+FilteredAudioOutput *
 audio_output_new(EventLoop &event_loop,
 		 const ReplayGainConfig &replay_gain_config,
 		 const ConfigBlock &block,
@@ -278,7 +278,7 @@ audio_output_new(EventLoop &event_loop,
 			      plugin->name);
 	}
 
-	AudioOutput *ao = ao_plugin_init(event_loop, *plugin, block);
+	auto *ao = ao_plugin_init(event_loop, *plugin, block);
 	assert(ao != nullptr);
 
 	try {
diff --git a/src/output/Internal.cxx b/src/output/Internal.cxx
index 1d90b47e9..5af69348e 100644
--- a/src/output/Internal.cxx
+++ b/src/output/Internal.cxx
@@ -29,7 +29,7 @@
 #include "util/StringBuffer.hxx"
 
 void
-AudioOutput::Enable()
+FilteredAudioOutput::Enable()
 {
 	try {
 		ao_plugin_enable(*this);
@@ -40,13 +40,13 @@ AudioOutput::Enable()
 }
 
 void
-AudioOutput::Disable() noexcept
+FilteredAudioOutput::Disable() noexcept
 {
 	ao_plugin_disable(*this);
 }
 
 void
-AudioOutput::ConfigureConvertFilter()
+FilteredAudioOutput::ConfigureConvertFilter()
 {
 	try {
 		convert_filter_set(convert_filter.Get(), out_audio_format);
@@ -57,7 +57,7 @@ AudioOutput::ConfigureConvertFilter()
 }
 
 void
-AudioOutput::OpenOutputAndConvert(AudioFormat desired_audio_format)
+FilteredAudioOutput::OpenOutputAndConvert(AudioFormat desired_audio_format)
 {
 	out_audio_format = desired_audio_format;
 
@@ -98,7 +98,7 @@ AudioOutput::OpenOutputAndConvert(AudioFormat desired_audio_format)
 }
 
 void
-AudioOutput::CloseOutput(bool drain) noexcept
+FilteredAudioOutput::CloseOutput(bool drain) noexcept
 {
 	if (drain)
 		ao_plugin_drain(*this);
@@ -109,21 +109,21 @@ AudioOutput::CloseOutput(bool drain) noexcept
 }
 
 void
-AudioOutput::OpenSoftwareMixer() noexcept
+FilteredAudioOutput::OpenSoftwareMixer() noexcept
 {
 	if (mixer != nullptr && mixer->IsPlugin(software_mixer_plugin))
 		software_mixer_set_filter(*mixer, volume_filter.Get());
 }
 
 void
-AudioOutput::CloseSoftwareMixer() noexcept
+FilteredAudioOutput::CloseSoftwareMixer() noexcept
 {
 	if (mixer != nullptr && mixer->IsPlugin(software_mixer_plugin))
 		software_mixer_set_filter(*mixer, nullptr);
 }
 
 void
-AudioOutput::Close(bool drain) noexcept
+FilteredAudioOutput::Close(bool drain) noexcept
 {
 	CloseOutput(drain);
 	CloseSoftwareMixer();
@@ -133,13 +133,13 @@ AudioOutput::Close(bool drain) noexcept
 }
 
 void
-AudioOutput::BeginPause() noexcept
+FilteredAudioOutput::BeginPause() noexcept
 {
 	ao_plugin_cancel(*this);
 }
 
 bool
-AudioOutput::IteratePause() noexcept
+FilteredAudioOutput::IteratePause() noexcept
 {
 	try {
 		return ao_plugin_pause(*this);
diff --git a/src/output/Internal.hxx b/src/output/Internal.hxx
index 4326fe1a3..3e374d733 100644
--- a/src/output/Internal.hxx
+++ b/src/output/Internal.hxx
@@ -33,7 +33,7 @@ struct ConfigBlock;
 struct AudioOutputPlugin;
 struct ReplayGainConfig;
 
-struct AudioOutput {
+struct FilteredAudioOutput {
 	/**
 	 * The device's configured display name.
 	 */
@@ -108,10 +108,10 @@ struct AudioOutput {
 	/**
 	 * Throws #std::runtime_error on error.
 	 */
-	AudioOutput(const AudioOutputPlugin &_plugin,
-		    const ConfigBlock &block);
+	FilteredAudioOutput(const AudioOutputPlugin &_plugin,
+			    const ConfigBlock &block);
 
-	~AudioOutput();
+	~FilteredAudioOutput();
 
 private:
 	void Configure(const ConfigBlock &block);
@@ -188,7 +188,7 @@ extern struct notify audio_output_client_notify;
 /**
  * Throws #std::runtime_error on error.
  */
-AudioOutput *
+FilteredAudioOutput *
 audio_output_new(EventLoop &event_loop,
 		 const ReplayGainConfig &replay_gain_config,
 		 const ConfigBlock &block,
diff --git a/src/output/MultipleOutputs.cxx b/src/output/MultipleOutputs.cxx
index 0be03f14c..13dd62809 100644
--- a/src/output/MultipleOutputs.cxx
+++ b/src/output/MultipleOutputs.cxx
@@ -49,7 +49,7 @@ MultipleOutputs::~MultipleOutputs()
 		i->FinishDestroy();
 }
 
-static AudioOutput *
+static FilteredAudioOutput *
 LoadOutput(EventLoop &event_loop,
 	   const ReplayGainConfig &replay_gain_config,
 	   MixerListener &mixer_listener,
diff --git a/src/output/MultipleOutputs.hxx b/src/output/MultipleOutputs.hxx
index 3febfeecb..65748a9be 100644
--- a/src/output/MultipleOutputs.hxx
+++ b/src/output/MultipleOutputs.hxx
@@ -42,7 +42,6 @@ class EventLoop;
 class MixerListener;
 class AudioOutputClient;
 struct MusicChunk;
-struct AudioOutput;
 struct ReplayGainConfig;
 
 class MultipleOutputs {
diff --git a/src/output/OutputPlugin.cxx b/src/output/OutputPlugin.cxx
index 51f02154b..882553513 100644
--- a/src/output/OutputPlugin.cxx
+++ b/src/output/OutputPlugin.cxx
@@ -21,7 +21,7 @@
 #include "OutputPlugin.hxx"
 #include "Internal.hxx"
 
-AudioOutput *
+FilteredAudioOutput *
 ao_plugin_init(EventLoop &event_loop,
 	       const AudioOutputPlugin &plugin,
 	       const ConfigBlock &block)
@@ -32,39 +32,39 @@ ao_plugin_init(EventLoop &event_loop,
 }
 
 void
-ao_plugin_finish(AudioOutput *ao) noexcept
+ao_plugin_finish(FilteredAudioOutput *ao) noexcept
 {
 	ao->plugin.finish(ao);
 }
 
 void
-ao_plugin_enable(AudioOutput &ao)
+ao_plugin_enable(FilteredAudioOutput &ao)
 {
 	if (ao.plugin.enable != nullptr)
 		ao.plugin.enable(&ao);
 }
 
 void
-ao_plugin_disable(AudioOutput &ao) noexcept
+ao_plugin_disable(FilteredAudioOutput &ao) noexcept
 {
 	if (ao.plugin.disable != nullptr)
 		ao.plugin.disable(&ao);
 }
 
 void
-ao_plugin_open(AudioOutput &ao, AudioFormat &audio_format)
+ao_plugin_open(FilteredAudioOutput &ao, AudioFormat &audio_format)
 {
 	ao.plugin.open(&ao, audio_format);
 }
 
 void
-ao_plugin_close(AudioOutput &ao) noexcept
+ao_plugin_close(FilteredAudioOutput &ao) noexcept
 {
 	ao.plugin.close(&ao);
 }
 
 std::chrono::steady_clock::duration
-ao_plugin_delay(AudioOutput &ao) noexcept
+ao_plugin_delay(FilteredAudioOutput &ao) noexcept
 {
 	return ao.plugin.delay != nullptr
 		? ao.plugin.delay(&ao)
@@ -72,34 +72,34 @@ ao_plugin_delay(AudioOutput &ao) noexcept
 }
 
 void
-ao_plugin_send_tag(AudioOutput &ao, const Tag &tag)
+ao_plugin_send_tag(FilteredAudioOutput &ao, const Tag &tag)
 {
 	if (ao.plugin.send_tag != nullptr)
 		ao.plugin.send_tag(&ao, tag);
 }
 
 size_t
-ao_plugin_play(AudioOutput &ao, const void *chunk, size_t size)
+ao_plugin_play(FilteredAudioOutput &ao, const void *chunk, size_t size)
 {
 	return ao.plugin.play(&ao, chunk, size);
 }
 
 void
-ao_plugin_drain(AudioOutput &ao)
+ao_plugin_drain(FilteredAudioOutput &ao)
 {
 	if (ao.plugin.drain != nullptr)
 		ao.plugin.drain(&ao);
 }
 
 void
-ao_plugin_cancel(AudioOutput &ao) noexcept
+ao_plugin_cancel(FilteredAudioOutput &ao) noexcept
 {
 	if (ao.plugin.cancel != nullptr)
 		ao.plugin.cancel(&ao);
 }
 
 bool
-ao_plugin_pause(AudioOutput &ao)
+ao_plugin_pause(FilteredAudioOutput &ao)
 {
 	return ao.plugin.pause != nullptr && ao.plugin.pause(&ao);
 }
diff --git a/src/output/OutputPlugin.hxx b/src/output/OutputPlugin.hxx
index 5ce52e15c..bea770b94 100644
--- a/src/output/OutputPlugin.hxx
+++ b/src/output/OutputPlugin.hxx
@@ -29,7 +29,7 @@
 struct ConfigBlock;
 struct AudioFormat;
 struct Tag;
-struct AudioOutput;
+struct FilteredAudioOutput;
 struct MixerPlugin;
 class EventLoop;
 
@@ -57,12 +57,12 @@ struct AudioOutputPlugin {
 	 * @param param the configuration section, or nullptr if there is
 	 * no configuration
 	 */
-	AudioOutput *(*init)(EventLoop &event_loop, const ConfigBlock &block);
+	FilteredAudioOutput *(*init)(EventLoop &event_loop, const ConfigBlock &block);
 
 	/**
 	 * Free resources allocated by this device.
 	 */
-	void (*finish)(AudioOutput *data);
+	void (*finish)(FilteredAudioOutput *data);
 
 	/**
 	 * Enable the device.  This may allocate resources, preparing
@@ -70,13 +70,13 @@ struct AudioOutputPlugin {
 	 *
 	 * Throws #std::runtime_error on error.
 	 */
-	void (*enable)(AudioOutput *data);
+	void (*enable)(FilteredAudioOutput *data);
 
 	/**
 	 * Disables the device.  It is closed before this method is
 	 * called.
 	 */
-	void (*disable)(AudioOutput *data);
+	void (*disable)(FilteredAudioOutput *data);
 
 	/**
 	 * Really open the device.
@@ -86,12 +86,12 @@ struct AudioOutputPlugin {
 	 * @param audio_format the audio format in which data is going
 	 * to be delivered; may be modified by the plugin
 	 */
-	void (*open)(AudioOutput *data, AudioFormat &audio_format);
+	void (*open)(FilteredAudioOutput *data, AudioFormat &audio_format);
 
 	/**
 	 * Close the device.
 	 */
-	void (*close)(AudioOutput *data);
+	void (*close)(FilteredAudioOutput *data);
 
 	/**
 	 * Returns a positive number if the output thread shall further
@@ -102,13 +102,13 @@ struct AudioOutputPlugin {
 	 *
 	 * @return the duration to wait
 	 */
-	std::chrono::steady_clock::duration (*delay)(AudioOutput *data) noexcept;
+	std::chrono::steady_clock::duration (*delay)(FilteredAudioOutput *data) noexcept;
 
 	/**
 	 * Display metadata for the next chunk.  Optional method,
 	 * because not all devices can display metadata.
 	 */
-	void (*send_tag)(AudioOutput *data, const Tag &tag);
+	void (*send_tag)(FilteredAudioOutput *data, const Tag &tag);
 
 	/**
 	 * Play a chunk of audio data.
@@ -117,19 +117,19 @@ struct AudioOutputPlugin {
 	 *
 	 * @return the number of bytes played
 	 */
-	size_t (*play)(AudioOutput *data,
+	size_t (*play)(FilteredAudioOutput *data,
 		       const void *chunk, size_t size);
 
 	/**
 	 * Wait until the device has finished playing.
 	 */
-	void (*drain)(AudioOutput *data);
+	void (*drain)(FilteredAudioOutput *data);
 
 	/**
 	 * Try to cancel data which may still be in the device's
 	 * buffers.
 	 */
-	void (*cancel)(AudioOutput *data);
+	void (*cancel)(FilteredAudioOutput *data);
 
 	/**
 	 * Pause the device.  If supported, it may perform a special
@@ -142,7 +142,7 @@ struct AudioOutputPlugin {
 	 * @return false on error (output will be closed by caller),
 	 * true for continue to pause
 	 */
-	bool (*pause)(AudioOutput *data);
+	bool (*pause)(FilteredAudioOutput *data);
 
 	/**
 	 * The mixer plugin associated with this output plugin.  This
@@ -162,43 +162,43 @@ ao_plugin_test_default_device(const AudioOutputPlugin *plugin)
 }
 
 gcc_malloc
-AudioOutput *
+FilteredAudioOutput *
 ao_plugin_init(EventLoop &event_loop,
 	       const AudioOutputPlugin &plugin,
 	       const ConfigBlock &block);
 
 void
-ao_plugin_finish(AudioOutput *ao) noexcept;
+ao_plugin_finish(FilteredAudioOutput *ao) noexcept;
 
 void
-ao_plugin_enable(AudioOutput &ao);
+ao_plugin_enable(FilteredAudioOutput &ao);
 
 void
-ao_plugin_disable(AudioOutput &ao) noexcept;
+ao_plugin_disable(FilteredAudioOutput &ao) noexcept;
 
 void
-ao_plugin_open(AudioOutput &ao, AudioFormat &audio_format);
+ao_plugin_open(FilteredAudioOutput &ao, AudioFormat &audio_format);
 
 void
-ao_plugin_close(AudioOutput &ao) noexcept;
+ao_plugin_close(FilteredAudioOutput &ao) noexcept;
 
 gcc_pure
 std::chrono::steady_clock::duration
-ao_plugin_delay(AudioOutput &ao) noexcept;
+ao_plugin_delay(FilteredAudioOutput &ao) noexcept;
 
 void
-ao_plugin_send_tag(AudioOutput &ao, const Tag &tag);
+ao_plugin_send_tag(FilteredAudioOutput &ao, const Tag &tag);
 
 size_t
-ao_plugin_play(AudioOutput &ao, const void *chunk, size_t size);
+ao_plugin_play(FilteredAudioOutput &ao, const void *chunk, size_t size);
 
 void
-ao_plugin_drain(AudioOutput &ao);
+ao_plugin_drain(FilteredAudioOutput &ao);
 
 void
-ao_plugin_cancel(AudioOutput &ao) noexcept;
+ao_plugin_cancel(FilteredAudioOutput &ao) noexcept;
 
 bool
-ao_plugin_pause(AudioOutput &ao);
+ao_plugin_pause(FilteredAudioOutput &ao);
 
 #endif
diff --git a/src/output/Wrapper.hxx b/src/output/Wrapper.hxx
index d7ef31166..f5a09afe7 100644
--- a/src/output/Wrapper.hxx
+++ b/src/output/Wrapper.hxx
@@ -30,68 +30,68 @@ struct Tag;
 
 template<class T>
 struct AudioOutputWrapper {
-	static T &Cast(AudioOutput &ao) {
+	static T &Cast(FilteredAudioOutput &ao) {
 		return ContainerCast(ao, &T::base);
 	}
 
-	static AudioOutput *Init(EventLoop &event_loop,
-				 const ConfigBlock &block) {
+	static FilteredAudioOutput *Init(EventLoop &event_loop,
+					 const ConfigBlock &block) {
 		T *t = T::Create(event_loop, block);
 		return &t->base;
 	}
 
-	static void Finish(AudioOutput *ao) {
+	static void Finish(FilteredAudioOutput *ao) {
 		T *t = &Cast(*ao);
 		delete t;
 	}
 
-	static void Enable(AudioOutput *ao) {
+	static void Enable(FilteredAudioOutput *ao) {
 		T &t = Cast(*ao);
 		t.Enable();
 	}
 
-	static void Disable(AudioOutput *ao) {
+	static void Disable(FilteredAudioOutput *ao) {
 		T &t = Cast(*ao);
 		t.Disable();
 	}
 
-	static void Open(AudioOutput *ao, AudioFormat &audio_format) {
+	static void Open(FilteredAudioOutput *ao, AudioFormat &audio_format) {
 		T &t = Cast(*ao);
 		t.Open(audio_format);
 	}
 
-	static void Close(AudioOutput *ao) {
+	static void Close(FilteredAudioOutput *ao) {
 		T &t = Cast(*ao);
 		t.Close();
 	}
 
 	gcc_pure
-	static std::chrono::steady_clock::duration Delay(AudioOutput *ao) noexcept {
+	static std::chrono::steady_clock::duration Delay(FilteredAudioOutput *ao) noexcept {
 		T &t = Cast(*ao);
 		return t.Delay();
 	}
 
-	static void SendTag(AudioOutput *ao, const Tag &tag) {
+	static void SendTag(FilteredAudioOutput *ao, const Tag &tag) {
 		T &t = Cast(*ao);
 		t.SendTag(tag);
 	}
 
-	static size_t Play(AudioOutput *ao, const void *chunk, size_t size) {
+	static size_t Play(FilteredAudioOutput *ao, const void *chunk, size_t size) {
 		T &t = Cast(*ao);
 		return t.Play(chunk, size);
 	}
 
-	static void Drain(AudioOutput *ao) {
+	static void Drain(FilteredAudioOutput *ao) {
 		T &t = Cast(*ao);
 		t.Drain();
 	}
 
-	static void Cancel(AudioOutput *ao) {
+	static void Cancel(FilteredAudioOutput *ao) {
 		T &t = Cast(*ao);
 		t.Cancel();
 	}
 
-	static bool Pause(AudioOutput *ao) {
+	static bool Pause(FilteredAudioOutput *ao) {
 		T &t = Cast(*ao);
 		return t.Pause();
 	}
diff --git a/src/output/plugins/AlsaOutputPlugin.cxx b/src/output/plugins/AlsaOutputPlugin.cxx
index 9fe0a3dd1..1d3d24869 100644
--- a/src/output/plugins/AlsaOutputPlugin.cxx
+++ b/src/output/plugins/AlsaOutputPlugin.cxx
@@ -64,7 +64,7 @@ class AlsaOutput final
 
 	friend struct AudioOutputWrapper<AlsaOutput>;
 
-	AudioOutput base;
+	FilteredAudioOutput base;
 
 	Manual<PcmExport> pcm_export;
 
diff --git a/src/output/plugins/AoOutputPlugin.cxx b/src/output/plugins/AoOutputPlugin.cxx
index b131e8994..0be06acd0 100644
--- a/src/output/plugins/AoOutputPlugin.cxx
+++ b/src/output/plugins/AoOutputPlugin.cxx
@@ -40,7 +40,7 @@ static unsigned ao_output_ref;
 class AoOutput {
 	friend struct AudioOutputWrapper<AoOutput>;
 
-	AudioOutput base;
+	FilteredAudioOutput base;
 
 	const size_t write_size;
 	int driver;
diff --git a/src/output/plugins/FifoOutputPlugin.cxx b/src/output/plugins/FifoOutputPlugin.cxx
index a57fd44b8..c001e2195 100644
--- a/src/output/plugins/FifoOutputPlugin.cxx
+++ b/src/output/plugins/FifoOutputPlugin.cxx
@@ -37,7 +37,7 @@
 class FifoOutput {
 	friend struct AudioOutputWrapper<FifoOutput>;
 
-	AudioOutput base;
+	FilteredAudioOutput base;
 
 	const AllocatedPath path;
 	std::string path_utf8;
diff --git a/src/output/plugins/HaikuOutputPlugin.cxx b/src/output/plugins/HaikuOutputPlugin.cxx
index ecf37c897..d6b8c5b2e 100644
--- a/src/output/plugins/HaikuOutputPlugin.cxx
+++ b/src/output/plugins/HaikuOutputPlugin.cxx
@@ -48,7 +48,7 @@ class HaikuOutput {
 	friend int haiku_output_get_volume(HaikuOutput &haiku);
 	friend bool haiku_output_set_volume(HaikuOutput &haiku, unsigned volume);
 
-	AudioOutput base;
+	FilteredAudioOutput base;
 
 	size_t write_size;
 
diff --git a/src/output/plugins/JackOutputPlugin.cxx b/src/output/plugins/JackOutputPlugin.cxx
index 4abc4b057..770de3fdb 100644
--- a/src/output/plugins/JackOutputPlugin.cxx
+++ b/src/output/plugins/JackOutputPlugin.cxx
@@ -43,7 +43,7 @@ static constexpr unsigned MAX_PORTS = 16;
 static constexpr size_t jack_sample_size = sizeof(jack_default_audio_sample_t);
 
 struct JackOutput {
-	AudioOutput base;
+	FilteredAudioOutput base;
 
 	/**
 	 * libjack options passed to jack_client_open().
@@ -443,7 +443,7 @@ JackOutput::Disable()
 	}
 }
 
-static AudioOutput *
+static FilteredAudioOutput *
 mpd_jack_init(EventLoop &, const ConfigBlock &block)
 {
 	jack_set_error_function(mpd_jack_error);
diff --git a/src/output/plugins/NullOutputPlugin.cxx b/src/output/plugins/NullOutputPlugin.cxx
index 1090f62b5..4603e16df 100644
--- a/src/output/plugins/NullOutputPlugin.cxx
+++ b/src/output/plugins/NullOutputPlugin.cxx
@@ -26,7 +26,7 @@
 class NullOutput {
 	friend struct AudioOutputWrapper<NullOutput>;
 
-	AudioOutput base;
+	FilteredAudioOutput base;
 
 	const bool sync;
 
diff --git a/src/output/plugins/OSXOutputPlugin.cxx b/src/output/plugins/OSXOutputPlugin.cxx
index c68deb88b..c619d2ec5 100644
--- a/src/output/plugins/OSXOutputPlugin.cxx
+++ b/src/output/plugins/OSXOutputPlugin.cxx
@@ -36,7 +36,7 @@
 #include <memory>
 
 struct OSXOutput {
-	AudioOutput base;
+	FilteredAudioOutput base;
 
 	/* configuration settings */
 	OSType component_subtype;
@@ -103,7 +103,7 @@ OSXOutput::OSXOutput(const ConfigBlock &block)
 	sync_sample_rate = block.GetBlockValue("sync_sample_rate", false);
 }
 
-static AudioOutput *
+static FilteredAudioOutput *
 osx_output_init(EventLoop &, const ConfigBlock &block)
 {
 	OSXOutput *oo = new OSXOutput(block);
@@ -128,7 +128,7 @@ osx_output_init(EventLoop &, const ConfigBlock &block)
 }
 
 static void
-osx_output_finish(AudioOutput *ao)
+osx_output_finish(FilteredAudioOutput *ao)
 {
 	OSXOutput *oo = (OSXOutput *)ao;
 
@@ -514,7 +514,7 @@ osx_render(void *vdata,
 }
 
 static void
-osx_output_enable(AudioOutput *ao)
+osx_output_enable(FilteredAudioOutput *ao)
 {
 	char errormsg[1024];
 	OSXOutput *oo = (OSXOutput *)ao;
@@ -550,7 +550,7 @@ osx_output_enable(AudioOutput *ao)
 }
 
 static void
-osx_output_disable(AudioOutput *ao)
+osx_output_disable(FilteredAudioOutput *ao)
 {
 	OSXOutput *oo = (OSXOutput *)ao;
 
@@ -562,7 +562,7 @@ osx_output_disable(AudioOutput *ao)
 }
 
 static void
-osx_output_close(AudioOutput *ao)
+osx_output_close(FilteredAudioOutput *ao)
 {
 	OSXOutput *od = (OSXOutput *)ao;
 
@@ -573,7 +573,7 @@ osx_output_close(AudioOutput *ao)
 }
 
 static void
-osx_output_open(AudioOutput *ao, AudioFormat &audio_format)
+osx_output_open(FilteredAudioOutput *ao, AudioFormat &audio_format)
 {
 	char errormsg[1024];
 	OSXOutput *od = (OSXOutput *)ao;
@@ -663,14 +663,14 @@ osx_output_open(AudioOutput *ao, AudioFormat &audio_format)
 }
 
 static size_t
-osx_output_play(AudioOutput *ao, const void *chunk, size_t size)
+osx_output_play(FilteredAudioOutput *ao, const void *chunk, size_t size)
 {
 	OSXOutput *od = (OSXOutput *)ao;
 	return od->ring_buffer->push((uint8_t *)chunk, size);
 }
 
 static std::chrono::steady_clock::duration
-osx_output_delay(AudioOutput *ao) noexcept
+osx_output_delay(FilteredAudioOutput *ao) noexcept
 {
 	OSXOutput *od = (OSXOutput *)ao;
 	return od->ring_buffer->write_available()
diff --git a/src/output/plugins/OpenALOutputPlugin.cxx b/src/output/plugins/OpenALOutputPlugin.cxx
index 4f31ad4ee..79d7c165e 100644
--- a/src/output/plugins/OpenALOutputPlugin.cxx
+++ b/src/output/plugins/OpenALOutputPlugin.cxx
@@ -39,7 +39,7 @@ class OpenALOutput {
 	/* should be enough for buffer size = 2048 */
 	static constexpr unsigned NUM_BUFFERS = 16;
 
-	AudioOutput base;
+	FilteredAudioOutput base;
 
 	const char *device_name;
 	ALCdevice *device;
diff --git a/src/output/plugins/OssOutputPlugin.cxx b/src/output/plugins/OssOutputPlugin.cxx
index 60237a537..b5fe87461 100644
--- a/src/output/plugins/OssOutputPlugin.cxx
+++ b/src/output/plugins/OssOutputPlugin.cxx
@@ -63,7 +63,7 @@
 class OssOutput {
 	friend struct AudioOutputWrapper<OssOutput>;
 
-	AudioOutput base;
+	FilteredAudioOutput base;
 
 #ifdef AFMT_S24_PACKED
 	Manual<PcmExport> pcm_export;
diff --git a/src/output/plugins/PipeOutputPlugin.cxx b/src/output/plugins/PipeOutputPlugin.cxx
index 7d5efb940..455b16fab 100644
--- a/src/output/plugins/PipeOutputPlugin.cxx
+++ b/src/output/plugins/PipeOutputPlugin.cxx
@@ -31,7 +31,7 @@
 class PipeOutput {
 	friend struct AudioOutputWrapper<PipeOutput>;
 
-	AudioOutput base;
+	FilteredAudioOutput base;
 
 	const std::string cmd;
 	FILE *fh;
diff --git a/src/output/plugins/PulseOutputPlugin.cxx b/src/output/plugins/PulseOutputPlugin.cxx
index cae66eb36..cd1f4c97b 100644
--- a/src/output/plugins/PulseOutputPlugin.cxx
+++ b/src/output/plugins/PulseOutputPlugin.cxx
@@ -47,7 +47,7 @@
 class PulseOutput {
 	friend struct AudioOutputWrapper<PulseOutput>;
 
-	AudioOutput base;
+	FilteredAudioOutput base;
 
 	const char *name;
 	const char *server;
diff --git a/src/output/plugins/RecorderOutputPlugin.cxx b/src/output/plugins/RecorderOutputPlugin.cxx
index 75705a609..075abf472 100644
--- a/src/output/plugins/RecorderOutputPlugin.cxx
+++ b/src/output/plugins/RecorderOutputPlugin.cxx
@@ -45,7 +45,7 @@ static constexpr Domain recorder_domain("recorder");
 class RecorderOutput {
 	friend struct AudioOutputWrapper<RecorderOutput>;
 
-	AudioOutput base;
+	FilteredAudioOutput base;
 
 	/**
 	 * The configured encoder plugin.
diff --git a/src/output/plugins/RoarOutputPlugin.cxx b/src/output/plugins/RoarOutputPlugin.cxx
index 15bd031f0..4963cf9f7 100644
--- a/src/output/plugins/RoarOutputPlugin.cxx
+++ b/src/output/plugins/RoarOutputPlugin.cxx
@@ -39,7 +39,7 @@
 class RoarOutput {
 	friend struct AudioOutputWrapper<RoarOutput>;
 
-	AudioOutput base;
+	FilteredAudioOutput base;
 
 	const std::string host, name;
 
@@ -54,7 +54,7 @@ class RoarOutput {
 public:
 	RoarOutput(const ConfigBlock &block);
 
-	operator AudioOutput *() {
+	operator FilteredAudioOutput *() {
 		return &base;
 	}
 
diff --git a/src/output/plugins/ShoutOutputPlugin.cxx b/src/output/plugins/ShoutOutputPlugin.cxx
index 847ab3b95..4126059b7 100644
--- a/src/output/plugins/ShoutOutputPlugin.cxx
+++ b/src/output/plugins/ShoutOutputPlugin.cxx
@@ -40,7 +40,7 @@
 static constexpr unsigned DEFAULT_CONN_TIMEOUT = 2;
 
 struct ShoutOutput final {
-	AudioOutput base;
+	FilteredAudioOutput base;
 
 	shout_t *shout_conn;
 	shout_metadata_t *shout_meta;
diff --git a/src/output/plugins/SndioOutputPlugin.cxx b/src/output/plugins/SndioOutputPlugin.cxx
index f8c154c1a..a0d7a3e48 100644
--- a/src/output/plugins/SndioOutputPlugin.cxx
+++ b/src/output/plugins/SndioOutputPlugin.cxx
@@ -47,7 +47,7 @@ static constexpr Domain sndio_output_domain("sndio_output");
 
 class SndioOutput {
 	friend struct AudioOutputWrapper<SndioOutput>;
-	AudioOutput base;
+	FilteredAudioOutput base;
 	const char *const device;
 	const unsigned buffer_time; /* in ms */
 	struct sio_hdl *sio_hdl;
diff --git a/src/output/plugins/SolarisOutputPlugin.cxx b/src/output/plugins/SolarisOutputPlugin.cxx
index 856a64ac0..ae4e71ff8 100644
--- a/src/output/plugins/SolarisOutputPlugin.cxx
+++ b/src/output/plugins/SolarisOutputPlugin.cxx
@@ -53,7 +53,7 @@ struct audio_info {
 class SolarisOutput {
 	friend struct AudioOutputWrapper<SolarisOutput>;
 
-	AudioOutput base;
+	FilteredAudioOutput base;
 
 	/* configuration */
 	const char *const device;
diff --git a/src/output/plugins/WinmmOutputPlugin.cxx b/src/output/plugins/WinmmOutputPlugin.cxx
index b17c65d3f..0a335eeaf 100644
--- a/src/output/plugins/WinmmOutputPlugin.cxx
+++ b/src/output/plugins/WinmmOutputPlugin.cxx
@@ -42,7 +42,7 @@ struct WinmmBuffer {
 class WinmmOutput {
 	friend struct AudioOutputWrapper<WinmmOutput>;
 
-	AudioOutput base;
+	FilteredAudioOutput base;
 
 	const UINT device_id;
 	HWAVEOUT handle;
diff --git a/src/output/plugins/httpd/HttpdInternal.hxx b/src/output/plugins/httpd/HttpdInternal.hxx
index 11d193d56..7726ea2c1 100644
--- a/src/output/plugins/httpd/HttpdInternal.hxx
+++ b/src/output/plugins/httpd/HttpdInternal.hxx
@@ -52,7 +52,7 @@ struct Tag;
 class HttpdOutput final : ServerSocket, DeferredMonitor {
 	friend struct AudioOutputWrapper<HttpdOutput>;
 
-	AudioOutput base;
+	FilteredAudioOutput base;
 
 	/**
 	 * True if the audio output is open and accepts client
@@ -160,7 +160,7 @@ public:
 	static HttpdOutput *Create(EventLoop &event_loop,
 				   const ConfigBlock &block);
 
-	static constexpr HttpdOutput *Cast(AudioOutput *ao) {
+	static constexpr HttpdOutput *Cast(FilteredAudioOutput *ao) {
 		return &ContainerCast(*ao, &HttpdOutput::base);
 	}
 
diff --git a/src/output/plugins/sles/SlesOutputPlugin.cxx b/src/output/plugins/sles/SlesOutputPlugin.cxx
index 4165dd20f..ca47f99a4 100644
--- a/src/output/plugins/sles/SlesOutputPlugin.cxx
+++ b/src/output/plugins/sles/SlesOutputPlugin.cxx
@@ -43,7 +43,7 @@ class SlesOutput {
 	static constexpr unsigned N_BUFFERS = 3;
 	static constexpr size_t BUFFER_SIZE = 65536;
 
-	AudioOutput base;
+	FilteredAudioOutput base;
 
 	SLES::Object engine_object, mix_object, play_object;
 	SLES::Play play;
@@ -89,7 +89,7 @@ class SlesOutput {
 public:
 	SlesOutput(const ConfigBlock &block);
 
-	operator AudioOutput *() {
+	operator FilteredAudioOutput *() {
 		return &base;
 	}
 
diff --git a/test/read_mixer.cxx b/test/read_mixer.cxx
index 4c7efabe3..f133e426d 100644
--- a/test/read_mixer.cxx
+++ b/test/read_mixer.cxx
@@ -51,7 +51,7 @@ try {
 	EventLoop event_loop;
 
 	Mixer *mixer = mixer_new(event_loop, alsa_mixer_plugin,
-				 *(AudioOutput *)nullptr,
+				 *(FilteredAudioOutput *)nullptr,
 				 *(MixerListener *)nullptr,
 				 ConfigBlock());
 
diff --git a/test/run_output.cxx b/test/run_output.cxx
index 9f6a87a60..f3e969fd8 100644
--- a/test/run_output.cxx
+++ b/test/run_output.cxx
@@ -49,7 +49,7 @@ filter_plugin_by_name(gcc_unused const char *name) noexcept
 	return NULL;
 }
 
-static AudioOutput *
+static FilteredAudioOutput *
 load_audio_output(EventLoop &event_loop, const char *name)
 {
 	const auto *param = config_find_block(ConfigBlockOption::AUDIO_OUTPUT,
@@ -63,7 +63,7 @@ load_audio_output(EventLoop &event_loop, const char *name)
 }
 
 static void
-run_output(AudioOutput &ao, AudioFormat audio_format)
+run_output(FilteredAudioOutput &ao, AudioFormat audio_format)
 {
 	/* open the audio output */
 
@@ -127,7 +127,7 @@ try {
 
 	/* initialize the audio output */
 
-	AudioOutput *ao = load_audio_output(io_thread.GetEventLoop(), argv[2]);
+	auto *ao = load_audio_output(io_thread.GetEventLoop(), argv[2]);
 
 	/* parse the audio format */