diff --git a/src/main/java/me/mrletsplay/videobase/Config.java b/src/main/java/me/mrletsplay/videobase/Config.java
index 8b7358c..43a3878 100644
--- a/src/main/java/me/mrletsplay/videobase/Config.java
+++ b/src/main/java/me/mrletsplay/videobase/Config.java
@@ -9,6 +9,9 @@ public class Config implements JSONConvertible {
 	@JSONValue
 	private String libraryPath;
 
+	@JSONValue
+	private boolean readOnly;
+
 	@JSONValue
 	private String cachePath;
 
@@ -19,6 +22,10 @@ public class Config implements JSONConvertible {
 		return libraryPath;
 	}
 
+	public boolean isReadOnly() {
+		return readOnly;
+	}
+
 	public String getCachePath() {
 		return cachePath;
 	}
@@ -26,6 +33,7 @@ public class Config implements JSONConvertible {
 	public static Config createDefault() {
 		Config config = new Config();
 		config.libraryPath = "library";
+		config.readOnly = false;
 		config.cachePath = "cache";
 		return config;
 	}
diff --git a/src/main/java/me/mrletsplay/videobase/VideoBase.java b/src/main/java/me/mrletsplay/videobase/VideoBase.java
index 3a14669..387fab0 100644
--- a/src/main/java/me/mrletsplay/videobase/VideoBase.java
+++ b/src/main/java/me/mrletsplay/videobase/VideoBase.java
@@ -81,7 +81,7 @@ public class VideoBase {
 	}
 
 	private static void loadLibrary() {
-		library = Library.load(Path.of(config.getLibraryPath()));
+		library = Library.load(Path.of(config.getLibraryPath()), config.isReadOnly());
 	}
 
 }
diff --git a/src/main/java/me/mrletsplay/videobase/library/Library.java b/src/main/java/me/mrletsplay/videobase/library/Library.java
index 1dee67d..b98b7aa 100644
--- a/src/main/java/me/mrletsplay/videobase/library/Library.java
+++ b/src/main/java/me/mrletsplay/videobase/library/Library.java
@@ -25,13 +25,15 @@ public class Library {
 		VIDEO_METADATA_SUFFIX = ".meta.json";
 
 	private Path path;
+	private boolean readOnly;
 	private List<Video> videos;
 
-	public Library(Path path, List<Video> videos) {
+	public Library(Path path, boolean readOnly, List<Video> videos) {
 		Objects.requireNonNull(path, "path");
 		Objects.requireNonNull(videos, "videos");
 
 		this.path = path;
+		this.readOnly = readOnly;
 		this.videos = videos;
 	}
 
@@ -39,6 +41,10 @@ public class Library {
 		return path;
 	}
 
+	public boolean isReadOnly() {
+		return readOnly;
+	}
+
 	public List<Video> getVideos() {
 		return videos;
 	}
@@ -78,8 +84,10 @@ public class Library {
 	}
 
 	public boolean updateMetadata(Video video, VideoMetadata metadata) {
+		if(readOnly) return false;
+
 		VideoMetadata oldMetadata = video.getMetadata();
-		VideoMetadata newMetadata = VideoMetadata.inherit(oldMetadata, metadata);
+		VideoMetadata newMetadata = VideoMetadata.inherit(oldMetadata.getParent(), metadata);
 
 		Path videoPath = video.getPath().toAbsolutePath();
 		try {
@@ -94,28 +102,32 @@ public class Library {
 	public boolean updateMetadata(String videoId, VideoMetadata metadata) {
 		Video video = findVideoById(videoId);
 		if(video == null) return false;
-		updateMetadata(video, metadata);
-		return true;
+		return updateMetadata(video, metadata);
 	}
 
-	public static Library load(Path path) {
+	public static Library load(Path path, boolean readOnly) {
 		List<Video> videos = new ArrayList<>();
 		load(path, path, videos, VideoMetadata.DEFAULT_METADATA);
-		return new Library(path, videos);
+		return new Library(path, readOnly, videos);
 	}
 
 	private static void load(Path rootPath, Path path, List<Video> videos, VideoMetadata parentDefaultMetadata) {
 		if(!Files.isDirectory(path)) return;
 
-		LibraryMetadata libraryMeta = null;
-		VideoMetadata defaultMetadata = parentDefaultMetadata;
+		LibraryMetadata libraryMetadata = null;
+
+		VideoMetadata inferredMetadata = new VideoMetadata(new JSONObject(Map.of(
+			VideoMetadata.FIELD_SERIES, path.getFileName().toString()
+		)));
+
+		VideoMetadata defaultMetadata = VideoMetadata.inherit(parentDefaultMetadata, inferredMetadata);
 
 		Path metaPath = path.resolve("meta.json");
 		if(Files.isRegularFile(metaPath)) {
 			try {
 				JSONObject obj = new JSONObject(Files.readString(metaPath));
-				libraryMeta = JSONConverter.decodeObject(obj, LibraryMetadata.class);
-				defaultMetadata = VideoMetadata.inherit(defaultMetadata, libraryMeta.getDefault());
+				libraryMetadata = JSONConverter.decodeObject(obj, LibraryMetadata.class);
+				defaultMetadata = VideoMetadata.inherit(defaultMetadata, libraryMetadata.getDefault());
 			}catch(IOException | JSONParseException | ClassCastException e) {
 				VideoBase.LOGGER.warn("Failed to parse metadata at " + path, e);
 			}
@@ -141,27 +153,26 @@ public class Library {
 					continue;
 				}
 
-				VideoMetadata inferredMetadata = new VideoMetadata(new JSONObject(Map.of(
-					VideoMetadata.FIELD_TITLE, fileNameNoExt,
-					VideoMetadata.FIELD_SERIES, path.getFileName().toString()
+				VideoMetadata inferredVideoMetadata = new VideoMetadata(new JSONObject(Map.of(
+					VideoMetadata.FIELD_TITLE, fileNameNoExt
 				)));
 
-				VideoMetadata videoMeta = VideoMetadata.inherit(defaultMetadata, inferredMetadata);
+				VideoMetadata videoMetadata = VideoMetadata.inherit(defaultMetadata, inferredVideoMetadata);
 
 				Path videoMetaPath = path.resolve(subPath.getFileName().toString() + VIDEO_METADATA_SUFFIX);
 				if(Files.isRegularFile(videoMetaPath)) {
 					try {
 						JSONObject obj = new JSONObject(Files.readString(videoMetaPath));
-						videoMeta = VideoMetadata.inherit(videoMeta, JSONConverter.decodeObject(obj, VideoMetadata.class));
+						videoMetadata = VideoMetadata.inherit(videoMetadata, JSONConverter.decodeObject(obj, VideoMetadata.class));
 					}catch(IOException | JSONParseException | ClassCastException e) {
 						VideoBase.LOGGER.warn("Failed to parse metadata at " + path, e);
 					}
-				}else if(libraryMeta != null && libraryMeta.getOverrides().containsKey(fileName)) {
-					videoMeta = VideoMetadata.inherit(videoMeta, libraryMeta.getOverrides().get(fileName));
+				}else if(libraryMetadata != null && libraryMetadata.getOverrides().containsKey(fileName)) {
+					videoMetadata = VideoMetadata.inherit(videoMetadata, libraryMetadata.getOverrides().get(fileName));
 				}
 
 				String id = Hash.hash(rootPath.relativize(subPath).toString());
-				videos.add(new Video(subPath, id, videoMeta == null ? VideoMetadata.DEFAULT_METADATA : videoMeta));
+				videos.add(new Video(subPath, id, videoMetadata == null ? VideoMetadata.DEFAULT_METADATA : videoMetadata));
 			}
 		}catch(IOException e) {
 			VideoBase.LOGGER.warn("Failed to load folder at " + path, e);
diff --git a/src/main/java/me/mrletsplay/videobase/library/VideoMetadata.java b/src/main/java/me/mrletsplay/videobase/library/VideoMetadata.java
index 2458272..f1f8e44 100644
--- a/src/main/java/me/mrletsplay/videobase/library/VideoMetadata.java
+++ b/src/main/java/me/mrletsplay/videobase/library/VideoMetadata.java
@@ -1,7 +1,6 @@
 package me.mrletsplay.videobase.library;
 
 import java.util.Map;
-import java.util.Objects;
 
 import me.mrletsplay.mrcore.json.JSONObject;
 import me.mrletsplay.mrcore.json.JSONType;
@@ -38,36 +37,61 @@ public class VideoMetadata implements JSONConvertible {
 		.optional(FIELD_AUTHOR, JSONType.STRING)
 		.optional(FIELD_INDEX, JSONType.INTEGER);
 
+	private VideoMetadata parent;
 	private JSONObject metadata;
+	private JSONObject cachedEffectiveMetadata;
 
 	@JSONConstructor
 	private VideoMetadata() {}
 
 	public VideoMetadata(JSONObject metadata) {
-		Objects.requireNonNull(metadata, "metadata");
-		this.metadata = metadata;
+		this.metadata = metadata == null ? new JSONObject() : metadata;
 	}
 
 	public String getSeries() {
-		return metadata.optString(FIELD_SERIES).orElse(null);
+		return getEffective().optString(FIELD_SERIES).orElse(null);
 	}
 
 	public String getTitle() {
-		return metadata.optString(FIELD_TITLE).orElse(null);
+		return getEffective().optString(FIELD_TITLE).orElse(null);
 	}
 
 	public String getAuthor() {
-		return metadata.optString(FIELD_AUTHOR).orElse(null);
+		return getEffective().optString(FIELD_AUTHOR).orElse(null);
 	}
 
 	public Integer getIndex() {
-		return metadata.optInt(FIELD_INDEX).orElse(null);
+		return getEffective().optInt(FIELD_INDEX).orElse(null);
+	}
+
+	public VideoMetadata getParent() {
+		return parent;
 	}
 
 	public JSONObject getRaw() {
 		return new JSONObject(metadata);
 	}
 
+	public JSONObject getEffective() {
+		if(cachedEffectiveMetadata != null) return cachedEffectiveMetadata;
+
+		JSONObject meta = new JSONObject(parent == null ? null : parent.getEffective());
+		for(String key : metadata.keys()) {
+			Object value = metadata.get(key);
+			if(value == null) { // Setting to null resets to default value if available, otherwise removes attribute
+				value = DEFAULT_METADATA.metadata.opt(key).orElse(null);
+				if(value == null) {
+					meta.remove(key);
+					continue;
+				}
+			}
+
+			meta.set(key, value);
+		}
+
+		return cachedEffectiveMetadata = meta;
+	}
+
 	@Override
 	public void preDeserialize(JSONObject object) {
 		this.metadata = object;
@@ -86,24 +110,9 @@ public class VideoMetadata implements JSONConvertible {
 	}
 
 	public static VideoMetadata inherit(VideoMetadata parent, VideoMetadata child) {
-		if(parent == null) return child;
-		if(child == null) return parent;
-
-		JSONObject meta = new JSONObject(parent == null ? null : parent.metadata);
-		for(String key : child.metadata.keys()) {
-			Object value = child.metadata.get(key);
-			if(value == null) { // Setting to null resets to default value if available, otherwise removes attribute
-				value = DEFAULT_METADATA.metadata.opt(key).orElse(null);
-				if(value == null) {
-					meta.remove(key);
-					continue;
-				}
-			}
-
-			meta.set(key, value);
-		}
-
-		return new VideoMetadata(meta);
+		VideoMetadata meta = new VideoMetadata(child == null ? null : child.getRaw());
+		meta.parent = parent;
+		return meta;
 	}
 
 }
diff --git a/src/main/java/me/mrletsplay/videobase/rest/LibraryAPI.java b/src/main/java/me/mrletsplay/videobase/rest/LibraryAPI.java
index 854d3a4..93696ed 100644
--- a/src/main/java/me/mrletsplay/videobase/rest/LibraryAPI.java
+++ b/src/main/java/me/mrletsplay/videobase/rest/LibraryAPI.java
@@ -98,19 +98,31 @@ public class LibraryAPI implements EndpointCollection {
 	}
 
 	@Endpoint(method = HttpRequestMethod.GET, path = "/video/{video}/metadata", pathPattern = true)
-	public void getMetadata(HttpRequestContext ctx, @RequestParameter("video") String videoId) {
+	public void getVideoMetadata(HttpRequestContext ctx, @RequestParameter("video") String videoId) {
 		Video video = VideoBase.getLibrary().findVideoById(videoId);
 		if(video == null) {
 			ctx.respond(HttpStatusCodes.NOT_FOUND_404, new TextResponse("Not found"));
 			return;
 		}
 
-		ctx.respond(HttpStatusCodes.OK_200, new JsonResponse(video.getMetadata().getRaw()));
+		VideoMetadata videoMetadata = video.getMetadata();
+
+		JSONObject meta = new JSONObject();
+		meta.put("raw", videoMetadata.getRaw());
+		meta.put("inherited", videoMetadata.getParent() == null ? new JSONObject() : videoMetadata.getParent().getEffective());
+		meta.put("effective", videoMetadata.getEffective());
+
+		ctx.respond(HttpStatusCodes.OK_200, new JsonResponse(meta));
 	}
 
 	@Endpoint(method = HttpRequestMethod.PUT, path = "/video/{video}/metadata", pathPattern = true)
 	public void updateVideoMetadata(HttpRequestContext ctx, @RequestParameter("video") String videoId) {
 		Library library = VideoBase.getLibrary();
+		if(library.isReadOnly()) {
+			ctx.respond(HttpStatusCodes.ACCESS_DENIED_403, new TextResponse("Library is read-only"));
+			return;
+		}
+
 		Video video = VideoBase.getLibrary().findVideoById(videoId);
 		if(video == null) {
 			ctx.respond(HttpStatusCodes.NOT_FOUND_404, new TextResponse("Not found"));
@@ -129,7 +141,11 @@ public class LibraryAPI implements EndpointCollection {
 			return;
 		}
 
-		library.updateMetadata(video, new VideoMetadata(metadata));
+		if(!library.updateMetadata(video, new VideoMetadata(metadata))) {
+			ctx.respond(HttpStatusCodes.INTERNAL_SERVER_ERROR_500, new TextResponse("Failed to update metadata"));
+			return;
+		}
+
 		ctx.respond(HttpStatusCodes.OK_200, new JsonResponse(video.getMetadata().getRaw()));
 	}
 
@@ -185,7 +201,7 @@ public class LibraryAPI implements EndpointCollection {
 	private JSONObject videoToJSON(Video video) {
 		JSONObject v = new JSONObject();
 		v.put("id", video.getId());
-		v.put("metadata", video.getMetadata().getRaw());
+		v.put("metadata", video.getMetadata().getEffective());
 		return v;
 	}
 
diff --git a/src/main/java/me/mrletsplay/videobase/util/ThumbnailCreator.java b/src/main/java/me/mrletsplay/videobase/util/ThumbnailCreator.java
index d52f289..ba871bc 100644
--- a/src/main/java/me/mrletsplay/videobase/util/ThumbnailCreator.java
+++ b/src/main/java/me/mrletsplay/videobase/util/ThumbnailCreator.java
@@ -68,6 +68,8 @@ public class ThumbnailCreator {
 			}
 
 			BufferedImage thumbnail = ImageIO.read(new ByteArrayInputStream(bOut.toByteArray()));
+			if(thumbnail == null) return null;
+
 			try(OutputStream out = Files.newOutputStream(thumbnailFile)) {
 				ImageIO.write(thumbnail, "PNG", out);
 			}