diff --git a/Audio/CogAudio.xcodeproj/project.pbxproj b/Audio/CogAudio.xcodeproj/project.pbxproj
index 5af87de58..211d6ad23 100644
--- a/Audio/CogAudio.xcodeproj/project.pbxproj
+++ b/Audio/CogAudio.xcodeproj/project.pbxproj
@@ -39,8 +39,13 @@
 		17D21EBD0B8BF44000D1EBDE /* AudioPlayer.h in Headers */ = {isa = PBXBuildFile; fileRef = 17D21EBB0B8BF44000D1EBDE /* AudioPlayer.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		17D21EBE0B8BF44000D1EBDE /* AudioPlayer.m in Sources */ = {isa = PBXBuildFile; fileRef = 17D21EBC0B8BF44000D1EBDE /* AudioPlayer.m */; };
 		17F94DD50B8D0F7000A34E87 /* PluginController.h in Headers */ = {isa = PBXBuildFile; fileRef = 17F94DD30B8D0F7000A34E87 /* PluginController.h */; settings = {ATTRIBUTES = (Public, ); }; };
-		17F94DD60B8D0F7000A34E87 /* PluginController.m in Sources */ = {isa = PBXBuildFile; fileRef = 17F94DD40B8D0F7000A34E87 /* PluginController.m */; };
+		17F94DD60B8D0F7000A34E87 /* PluginController.mm in Sources */ = {isa = PBXBuildFile; fileRef = 17F94DD40B8D0F7000A34E87 /* PluginController.mm */; };
 		17F94DDD0B8D101100A34E87 /* Plugin.h in Headers */ = {isa = PBXBuildFile; fileRef = 17F94DDC0B8D101100A34E87 /* Plugin.h */; settings = {ATTRIBUTES = (Public, ); }; };
+		8328995327CB511000D7F028 /* RedundantPlaylistDataStore.m in Sources */ = {isa = PBXBuildFile; fileRef = 8328995127CB510F00D7F028 /* RedundantPlaylistDataStore.m */; };
+		8328995427CB511000D7F028 /* RedundantPlaylistDataStore.h in Headers */ = {isa = PBXBuildFile; fileRef = 8328995227CB511000D7F028 /* RedundantPlaylistDataStore.h */; };
+		8328995727CB51B700D7F028 /* SHA256Digest.h in Headers */ = {isa = PBXBuildFile; fileRef = 8328995527CB51B700D7F028 /* SHA256Digest.h */; };
+		8328995827CB51B700D7F028 /* SHA256Digest.m in Sources */ = {isa = PBXBuildFile; fileRef = 8328995627CB51B700D7F028 /* SHA256Digest.m */; };
+		8328995A27CB51C900D7F028 /* Security.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 8328995927CB51C900D7F028 /* Security.framework */; };
 		8347C7412796C58800FA8A7D /* NSFileHandle+CreateFile.h in Headers */ = {isa = PBXBuildFile; fileRef = 8347C73F2796C58800FA8A7D /* NSFileHandle+CreateFile.h */; };
 		8347C7422796C58800FA8A7D /* NSFileHandle+CreateFile.m in Sources */ = {isa = PBXBuildFile; fileRef = 8347C7402796C58800FA8A7D /* NSFileHandle+CreateFile.m */; };
 		834FD4EB27AF8F380063BC83 /* AudioChunk.h in Headers */ = {isa = PBXBuildFile; fileRef = 834FD4EA27AF8F380063BC83 /* AudioChunk.h */; };
@@ -139,9 +144,14 @@
 		17D21EBB0B8BF44000D1EBDE /* AudioPlayer.h */ = {isa = PBXFileReference; fileEncoding = 30; lastKnownFileType = sourcecode.c.h; path = AudioPlayer.h; sourceTree = "<group>"; };
 		17D21EBC0B8BF44000D1EBDE /* AudioPlayer.m */ = {isa = PBXFileReference; fileEncoding = 30; lastKnownFileType = sourcecode.c.objc; path = AudioPlayer.m; sourceTree = "<group>"; };
 		17F94DD30B8D0F7000A34E87 /* PluginController.h */ = {isa = PBXFileReference; fileEncoding = 30; lastKnownFileType = sourcecode.c.h; path = PluginController.h; sourceTree = "<group>"; };
-		17F94DD40B8D0F7000A34E87 /* PluginController.m */ = {isa = PBXFileReference; fileEncoding = 30; lastKnownFileType = sourcecode.c.objc; path = PluginController.m; sourceTree = "<group>"; };
+		17F94DD40B8D0F7000A34E87 /* PluginController.mm */ = {isa = PBXFileReference; fileEncoding = 30; lastKnownFileType = sourcecode.cpp.objcpp; path = PluginController.mm; sourceTree = "<group>"; };
 		17F94DDC0B8D101100A34E87 /* Plugin.h */ = {isa = PBXFileReference; fileEncoding = 30; lastKnownFileType = sourcecode.c.h; path = Plugin.h; sourceTree = "<group>"; };
 		32DBCF5E0370ADEE00C91783 /* CogAudio_Prefix.pch */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = CogAudio_Prefix.pch; sourceTree = "<group>"; };
+		8328995127CB510F00D7F028 /* RedundantPlaylistDataStore.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; name = RedundantPlaylistDataStore.m; path = ../../Utils/RedundantPlaylistDataStore.m; sourceTree = "<group>"; };
+		8328995227CB511000D7F028 /* RedundantPlaylistDataStore.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = RedundantPlaylistDataStore.h; path = ../../Utils/RedundantPlaylistDataStore.h; sourceTree = "<group>"; };
+		8328995527CB51B700D7F028 /* SHA256Digest.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = SHA256Digest.h; path = ../../Utils/SHA256Digest.h; sourceTree = "<group>"; };
+		8328995627CB51B700D7F028 /* SHA256Digest.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; name = SHA256Digest.m; path = ../../Utils/SHA256Digest.m; sourceTree = "<group>"; };
+		8328995927CB51C900D7F028 /* Security.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = Security.framework; path = System/Library/Frameworks/Security.framework; sourceTree = SDKROOT; };
 		8347C73F2796C58800FA8A7D /* NSFileHandle+CreateFile.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = "NSFileHandle+CreateFile.h"; path = "../../Utils/NSFileHandle+CreateFile.h"; sourceTree = "<group>"; };
 		8347C7402796C58800FA8A7D /* NSFileHandle+CreateFile.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; name = "NSFileHandle+CreateFile.m"; path = "../../Utils/NSFileHandle+CreateFile.m"; sourceTree = "<group>"; };
 		834FD4EA27AF8F380063BC83 /* AudioChunk.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = AudioChunk.h; sourceTree = "<group>"; };
@@ -190,6 +200,7 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				8328995A27CB51C900D7F028 /* Security.framework in Frameworks */,
 				83725A9127AA16D50003F694 /* AVFoundation.framework in Frameworks */,
 				8DC2EF570486A6940098B216 /* Cocoa.framework in Frameworks */,
 				83725A9027AA16C90003F694 /* Accelerate.framework in Frameworks */,
@@ -264,7 +275,7 @@
 				839366651815923C006DD712 /* CogPluginMulti.h */,
 				839366661815923C006DD712 /* CogPluginMulti.m */,
 				17F94DD30B8D0F7000A34E87 /* PluginController.h */,
-				17F94DD40B8D0F7000A34E87 /* PluginController.m */,
+				17F94DD40B8D0F7000A34E87 /* PluginController.mm */,
 				17D21C750B8BE4BA00D1EBDE /* Chain */,
 				17D21C9B0B8BE4BA00D1EBDE /* Output */,
 				17D21C9E0B8BE4BA00D1EBDE /* Status.h */,
@@ -349,6 +360,10 @@
 		17D21CDC0B8BE5B400D1EBDE /* Utils */ = {
 			isa = PBXGroup;
 			children = (
+				8328995527CB51B700D7F028 /* SHA256Digest.h */,
+				8328995627CB51B700D7F028 /* SHA256Digest.m */,
+				8328995227CB511000D7F028 /* RedundantPlaylistDataStore.h */,
+				8328995127CB510F00D7F028 /* RedundantPlaylistDataStore.m */,
 				835FAC5C27BCA14D00BA8562 /* BadSampleCleaner.h */,
 				835FAC5D27BCA14D00BA8562 /* BadSampleCleaner.m */,
 				8399CF2A27B5D1D4008751F1 /* NSDictionary+Merge.h */,
@@ -436,6 +451,7 @@
 		83725A8F27AA16C90003F694 /* Frameworks */ = {
 			isa = PBXGroup;
 			children = (
+				8328995927CB51C900D7F028 /* Security.framework */,
 			);
 			name = Frameworks;
 			sourceTree = "<group>";
@@ -470,6 +486,7 @@
 				17D21CA70B8BE4BA00D1EBDE /* Node.h in Headers */,
 				8399CF2C27B5D1D5008751F1 /* NSDictionary+Merge.h in Headers */,
 				17D21CA90B8BE4BA00D1EBDE /* OutputNode.h in Headers */,
+				8328995427CB511000D7F028 /* RedundantPlaylistDataStore.h in Headers */,
 				17D21CC50B8BE4BA00D1EBDE /* OutputCoreAudio.h in Headers */,
 				834FD4F427AFA2150063BC83 /* Downmix.h in Headers */,
 				17D21CC70B8BE4BA00D1EBDE /* Status.h in Headers */,
@@ -481,6 +498,7 @@
 				834FD4F027AF93680063BC83 /* ChunkList.h in Headers */,
 				17F94DD50B8D0F7000A34E87 /* PluginController.h in Headers */,
 				17F94DDD0B8D101100A34E87 /* Plugin.h in Headers */,
+				8328995727CB51B700D7F028 /* SHA256Digest.h in Headers */,
 				834FD4EB27AF8F380063BC83 /* AudioChunk.h in Headers */,
 				17A2D3C50B8D1D37000778C4 /* AudioDecoder.h in Headers */,
 				8347C7412796C58800FA8A7D /* NSFileHandle+CreateFile.h in Headers */,
@@ -590,12 +608,14 @@
 				17D21CF40B8BE5EF00D1EBDE /* Semaphore.m in Sources */,
 				8347C7422796C58800FA8A7D /* NSFileHandle+CreateFile.m in Sources */,
 				17D21DC80B8BE79700D1EBDE /* CoreAudioUtils.m in Sources */,
+				8328995327CB511000D7F028 /* RedundantPlaylistDataStore.m in Sources */,
 				8377C64C27B8C51500E8BC0F /* fft_accelerate.c in Sources */,
 				839366681815923C006DD712 /* CogPluginMulti.m in Sources */,
 				835C88AA2797D4D400E28EAE /* lpc.c in Sources */,
 				17D21EBE0B8BF44000D1EBDE /* AudioPlayer.m in Sources */,
-				17F94DD60B8D0F7000A34E87 /* PluginController.m in Sources */,
+				17F94DD60B8D0F7000A34E87 /* PluginController.mm in Sources */,
 				17A2D3C60B8D1D37000778C4 /* AudioDecoder.m in Sources */,
+				8328995827CB51B700D7F028 /* SHA256Digest.m in Sources */,
 				17C940240B900909008627D6 /* AudioMetadataReader.m in Sources */,
 				17B619310B909BC300BC003F /* AudioPropertiesReader.m in Sources */,
 				17ADB13D0B97926D00257CA2 /* AudioSource.m in Sources */,
diff --git a/Audio/PluginController.m b/Audio/PluginController.mm
similarity index 82%
rename from Audio/PluginController.m
rename to Audio/PluginController.mm
index 89068d408..1b52df1a4 100644
--- a/Audio/PluginController.m
+++ b/Audio/PluginController.mm
@@ -8,6 +8,125 @@
 
 #import "NSDictionary+Merge.h"
 
+#import "RedundantPlaylistDataStore.h"
+
+#import <chrono>
+#import <map>
+#import <mutex>
+#import <thread>
+
+struct Cached_Metadata {
+	std::chrono::steady_clock::time_point time_accessed;
+	NSDictionary *properties;
+	NSDictionary *metadata;
+	Cached_Metadata()
+	: properties(nil), metadata(nil) {
+	}
+};
+
+static std::mutex Cache_Lock;
+
+static std::map<std::string, Cached_Metadata> Cache_List;
+
+static RedundantPlaylistDataStore *Cache_Data_Store = nil;
+
+static bool Cache_Running = false;
+
+static std::thread *Cache_Thread = NULL;
+
+static void cache_run();
+
+static void cache_init() {
+	Cache_Data_Store = [[RedundantPlaylistDataStore alloc] init];
+	Cache_Thread = new std::thread(cache_run);
+}
+
+static void cache_deinit() {
+	Cache_Running = false;
+	Cache_Thread->join();
+	delete Cache_Thread;
+	Cache_Data_Store = nil;
+}
+
+static void cache_insert_properties(NSURL *url, NSDictionary *properties) {
+	std::lock_guard<std::mutex> lock(Cache_Lock);
+
+	std::string path = [[url absoluteString] UTF8String];
+	properties = [Cache_Data_Store coalesceEntryInfo:properties];
+
+	Cached_Metadata &entry = Cache_List[path];
+
+	entry.properties = properties;
+	entry.time_accessed = std::chrono::steady_clock::now();
+}
+
+static void cache_insert_metadata(NSURL *url, NSDictionary *metadata) {
+	std::lock_guard<std::mutex> lock(Cache_Lock);
+
+	std::string path = [[url absoluteString] UTF8String];
+	metadata = [Cache_Data_Store coalesceEntryInfo:metadata];
+
+	Cached_Metadata &entry = Cache_List[path];
+
+	entry.metadata = metadata;
+	entry.time_accessed = std::chrono::steady_clock::now();
+}
+
+static NSDictionary *cache_access_properties(NSURL *url) {
+	std::lock_guard<std::mutex> lock(Cache_Lock);
+
+	std::string path = [[url absoluteString] UTF8String];
+
+	Cached_Metadata &entry = Cache_List[path];
+
+	if(entry.properties) {
+		entry.time_accessed = std::chrono::steady_clock::now();
+		return entry.properties;
+	}
+
+	return nil;
+}
+
+static NSDictionary *cache_access_metadata(NSURL *url) {
+	std::lock_guard<std::mutex> lock(Cache_Lock);
+
+	std::string path = [[url absoluteString] UTF8String];
+
+	Cached_Metadata &entry = Cache_List[path];
+
+	if(entry.metadata) {
+		entry.time_accessed = std::chrono::steady_clock::now();
+		return entry.metadata;
+	}
+
+	return nil;
+}
+
+static void cache_run() {
+	std::chrono::milliseconds dura(250);
+
+	while(Cache_Running) {
+		std::chrono::steady_clock::time_point now = std::chrono::steady_clock::now();
+
+		{
+			std::lock_guard<std::mutex> lock(Cache_Lock);
+			for(auto it = Cache_List.begin(); it != Cache_List.end();) {
+				auto elapsed = std::chrono::duration_cast<std::chrono::seconds>(now - it->second.time_accessed);
+				if(elapsed.count() >= 10) {
+					it = Cache_List.erase(it);
+					continue;
+				}
+				++it;
+			}
+
+			if(Cache_List.size() == 0)
+				[Cache_Data_Store reset];
+		}
+
+		std::this_thread::sleep_for(dura);
+	}
+}
+
 @implementation PluginController
 
 @synthesize sources;
@@ -49,11 +168,17 @@ static PluginController *sharedPluginController = nil;
 		self.decodersByMimeType = [[NSMutableDictionary alloc] init];
 
 		[self setup];
+
+		cache_init();
 	}
 
 	return self;
 }
 
+- (void)dealloc {
+	cache_deinit();
+}
+
 - (void)setup {
 	if(self.configured == NO) {
 		self.configured = YES;
@@ -457,6 +582,9 @@ static PluginController *sharedPluginController = nil;
 	   [urlScheme isEqualToString:@"https"])
 		return nil;
 
+	NSDictionary *cacheData = cache_access_metadata(url);
+	if(cacheData) return cacheData;
+
 	NSString *ext = [url pathExtension];
 	NSArray *readers = [metadataReaders objectForKey:[ext lowercaseString]];
 	NSString *classString;
@@ -470,9 +598,13 @@ static PluginController *sharedPluginController = nil;
 					else
 						++i;
 				}
-				return [CogMetadataReaderMulti metadataForURL:url readers:_readers];
+				cacheData = [CogMetadataReaderMulti metadataForURL:url readers:_readers];
+				cache_insert_metadata(url, cacheData);
+				return cacheData;
 			}
-			return [CogMetadataReaderMulti metadataForURL:url readers:readers];
+			cacheData = [CogMetadataReaderMulti metadataForURL:url readers:readers];
+			cache_insert_metadata(url, cacheData);
+			return cacheData;
 		} else {
 			classString = [readers objectAtIndex:0];
 		}
@@ -482,7 +614,9 @@ static PluginController *sharedPluginController = nil;
 
 	Class metadataReader = NSClassFromString(classString);
 
-	return [metadataReader metadataForURL:url];
+	cacheData = [metadataReader metadataForURL:url];
+	cache_insert_metadata(url, cacheData);
+	return cacheData;
 }
 
 // If no properties reader is defined, use the decoder's properties.
@@ -493,6 +627,10 @@ static PluginController *sharedPluginController = nil;
 		return nil;
 
 	NSDictionary *properties = nil;
+
+	properties = cache_access_properties(url);
+	if(properties) return properties;
+
 	NSString *ext = [url pathExtension];
 
 	id<CogSource> source = [self audioSourceForURL:url];
@@ -504,8 +642,10 @@ static PluginController *sharedPluginController = nil;
 	if(readers) {
 		if([readers count] > 1) {
 			properties = [CogPropertiesReaderMulti propertiesForSource:source readers:readers];
-			if(properties != nil && [properties count])
+			if(properties != nil && [properties count]) {
+				cache_insert_properties(url, properties);
 				return properties;
+			}
 		} else {
 			classString = [readers objectAtIndex:0];
 		}
@@ -514,8 +654,10 @@ static PluginController *sharedPluginController = nil;
 		if(readers) {
 			if([readers count] > 1) {
 				properties = [CogPropertiesReaderMulti propertiesForSource:source readers:readers];
-				if(properties != nil && [properties count])
+				if(properties != nil && [properties count]) {
+					cache_insert_properties(url, properties);
 					return properties;
+				}
 			} else {
 				classString = [readers objectAtIndex:0];
 			}
@@ -526,8 +668,10 @@ static PluginController *sharedPluginController = nil;
 		Class propertiesReader = NSClassFromString(classString);
 
 		properties = [propertiesReader propertiesForSource:source];
-		if(properties != nil && [properties count])
+		if(properties != nil && [properties count]) {
+			cache_insert_properties(url, properties);
 			return properties;
+		}
 	}
 
 	{
@@ -541,7 +685,9 @@ static PluginController *sharedPluginController = nil;
 
 		[decoder close];
 
-		return [NSDictionary dictionaryByMerging:properties with:metadata];
+		NSDictionary *cacheData = [NSDictionary dictionaryByMerging:properties with:metadata];
+		cache_insert_properties(url, cacheData);
+		return cacheData;
 	}
 }
 
diff --git a/Utils/RedundantPlaylistDataStore.h b/Utils/RedundantPlaylistDataStore.h
index 2927f7fa5..2b2899e0d 100644
--- a/Utils/RedundantPlaylistDataStore.h
+++ b/Utils/RedundantPlaylistDataStore.h
@@ -21,6 +21,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (id)init;
 - (NSDictionary *)coalesceEntryInfo:(NSDictionary *)pe;
+- (void)reset;
 
 @end
 
diff --git a/Utils/RedundantPlaylistDataStore.m b/Utils/RedundantPlaylistDataStore.m
index f8b96f0ee..19c00d82e 100644
--- a/Utils/RedundantPlaylistDataStore.m
+++ b/Utils/RedundantPlaylistDataStore.m
@@ -69,4 +69,9 @@
 	return [NSDictionary dictionaryWithDictionary:ret];
 }
 
+- (void)reset {
+	[stringStore removeAllObjects];
+	[artStore removeAllObjects];
+}
+
 @end