diff --git a/src/Partition.cxx b/src/Partition.cxx
index 8aca29dde..f3027e05c 100644
--- a/src/Partition.cxx
+++ b/src/Partition.cxx
@@ -45,10 +45,10 @@ Partition::EmitIdle(unsigned mask)
 void
 Partition::UpdateEffectiveReplayGainMode(ReplayGainMode mode)
 {
-	if (mode == REPLAY_GAIN_AUTO)
+	if (mode == ReplayGainMode::AUTO)
 	    mode = playlist.queue.random
-		    ? REPLAY_GAIN_TRACK
-		    : REPLAY_GAIN_ALBUM;
+		    ? ReplayGainMode::TRACK
+		    : ReplayGainMode::ALBUM;
 
 	outputs.SetReplayGainMode(mode);
 }
diff --git a/src/Partition.hxx b/src/Partition.hxx
index 5cfba615e..b7bccca6b 100644
--- a/src/Partition.hxx
+++ b/src/Partition.hxx
@@ -178,7 +178,7 @@ struct Partition final : QueueListener, PlayerListener, MixerListener {
 
 	/**
 	 * Publishes the effective #ReplayGainMode to all subsystems.
-	 * #REPLAY_GAIN_AUTO is substituted.
+	 * #ReplayGainMode::AUTO is substituted.
 	 *
 	 * @param mode the configured mode
 	 */
diff --git a/src/ReplayGainConfig.cxx b/src/ReplayGainConfig.cxx
index 98b555abe..68b8c4b77 100644
--- a/src/ReplayGainConfig.cxx
+++ b/src/ReplayGainConfig.cxx
@@ -28,7 +28,7 @@
 #include <string.h>
 #include <math.h>
 
-ReplayGainMode replay_gain_mode = REPLAY_GAIN_OFF;
+ReplayGainMode replay_gain_mode = ReplayGainMode::OFF;
 
 static constexpr bool DEFAULT_REPLAYGAIN_LIMIT = true;
 
@@ -40,16 +40,16 @@ const char *
 replay_gain_get_mode_string(void)
 {
 	switch (replay_gain_mode) {
-	case REPLAY_GAIN_AUTO:
+	case ReplayGainMode::AUTO:
 		return "auto";
 
-	case REPLAY_GAIN_OFF:
+	case ReplayGainMode::OFF:
 		return "off";
 
-	case REPLAY_GAIN_TRACK:
+	case ReplayGainMode::TRACK:
 		return "track";
 
-	case REPLAY_GAIN_ALBUM:
+	case ReplayGainMode::ALBUM:
 		return "album";
 	}
 
@@ -63,13 +63,13 @@ replay_gain_set_mode_string(const char *p)
 	assert(p != nullptr);
 
 	if (strcmp(p, "off") == 0)
-		replay_gain_mode = REPLAY_GAIN_OFF;
+		replay_gain_mode = ReplayGainMode::OFF;
 	else if (strcmp(p, "track") == 0)
-		replay_gain_mode = REPLAY_GAIN_TRACK;
+		replay_gain_mode = ReplayGainMode::TRACK;
 	else if (strcmp(p, "album") == 0)
-		replay_gain_mode = REPLAY_GAIN_ALBUM;
+		replay_gain_mode = ReplayGainMode::ALBUM;
 	else if (strcmp(p, "auto") == 0)
-		replay_gain_mode = REPLAY_GAIN_AUTO;
+		replay_gain_mode = ReplayGainMode::AUTO;
 	else
 		return false;
 
diff --git a/src/ReplayGainInfo.hxx b/src/ReplayGainInfo.hxx
index 9bcd3f0f0..ae14635ad 100644
--- a/src/ReplayGainInfo.hxx
+++ b/src/ReplayGainInfo.hxx
@@ -50,7 +50,7 @@ struct ReplayGainInfo {
 	}
 
 	const ReplayGainTuple &Get(ReplayGainMode mode) const {
-		return mode == REPLAY_GAIN_ALBUM
+		return mode == ReplayGainMode::ALBUM
 			? (album.IsDefined() ? album : track)
 			: (track.IsDefined() ? track : album);
 	}
diff --git a/src/ReplayGainMode.hxx b/src/ReplayGainMode.hxx
index 8893aba14..c564cda9c 100644
--- a/src/ReplayGainMode.hxx
+++ b/src/ReplayGainMode.hxx
@@ -20,11 +20,13 @@
 #ifndef MPD_REPLAY_GAIN_MODE_HXX
 #define MPD_REPLAY_GAIN_MODE_HXX
 
-enum ReplayGainMode {
-	REPLAY_GAIN_AUTO = -2,
-	REPLAY_GAIN_OFF,
-	REPLAY_GAIN_ALBUM,
-	REPLAY_GAIN_TRACK,
+#include <stdint.h>
+
+enum class ReplayGainMode : uint8_t {
+	OFF,
+	ALBUM,
+	TRACK,
+	AUTO,
 };
 
 #endif
diff --git a/src/decoder/Bridge.cxx b/src/decoder/Bridge.cxx
index 633f2a55a..f878a6708 100644
--- a/src/decoder/Bridge.cxx
+++ b/src/decoder/Bridge.cxx
@@ -592,10 +592,10 @@ DecoderBridge::SubmitReplayGain(const ReplayGainInfo *new_replay_gain_info)
 		if (++serial == 0)
 			serial = 1;
 
-		if (REPLAY_GAIN_OFF != replay_gain_mode) {
+		if (ReplayGainMode::OFF != replay_gain_mode) {
 			ReplayGainMode rgm = replay_gain_mode;
-			if (rgm != REPLAY_GAIN_ALBUM)
-				rgm = REPLAY_GAIN_TRACK;
+			if (rgm != ReplayGainMode::ALBUM)
+				rgm = ReplayGainMode::TRACK;
 
 			const auto &tuple = new_replay_gain_info->Get(rgm);
 			const auto scale =
diff --git a/src/filter/plugins/ReplayGainFilterPlugin.cxx b/src/filter/plugins/ReplayGainFilterPlugin.cxx
index da4a3bca2..3c8ce751d 100644
--- a/src/filter/plugins/ReplayGainFilterPlugin.cxx
+++ b/src/filter/plugins/ReplayGainFilterPlugin.cxx
@@ -50,7 +50,7 @@ class ReplayGainFilter final : public Filter {
 	 */
 	const unsigned base;
 
-	ReplayGainMode mode = REPLAY_GAIN_OFF;
+	ReplayGainMode mode = ReplayGainMode::OFF;
 
 	ReplayGainInfo info;
 
@@ -72,7 +72,7 @@ public:
 	ReplayGainFilter(const AudioFormat &audio_format,
 			 Mixer *_mixer, unsigned _base)
 		:Filter(audio_format),
-		 mixer(_mixer), base(_base), mode(REPLAY_GAIN_OFF) {
+		 mixer(_mixer), base(_base) {
 		info.Clear();
 
 		pv.Open(out_audio_format.format);
@@ -94,7 +94,7 @@ public:
 
 		FormatDebug(replay_gain_domain,
 			    "replay gain mode has changed %d->%d\n",
-			    mode, _mode);
+			    (int)mode, (int)_mode);
 
 		mode = _mode;
 		Update();
@@ -138,7 +138,7 @@ void
 ReplayGainFilter::Update()
 {
 	unsigned volume = PCM_VOLUME_1;
-	if (mode != REPLAY_GAIN_OFF) {
+	if (mode != ReplayGainMode::OFF) {
 		const auto &tuple = info.Get(mode);
 		float scale = tuple.CalculateScale(replay_gain_preamp,
 						   replay_gain_missing_preamp,
diff --git a/src/output/Internal.hxx b/src/output/Internal.hxx
index 2c5f4ba56..393269690 100644
--- a/src/output/Internal.hxx
+++ b/src/output/Internal.hxx
@@ -148,7 +148,7 @@ struct AudioOutput {
 	 */
 	bool woken_for_play = false;
 
-	ReplayGainMode replay_gain_mode = REPLAY_GAIN_OFF;
+	ReplayGainMode replay_gain_mode = ReplayGainMode::OFF;
 
 	/**
 	 * If not nullptr, the device has failed, and this timer is used