diff --git a/aegisub/libaegisub/common/log.cpp b/aegisub/libaegisub/common/log.cpp
index e0465eb0f..7bb434f4c 100644
--- a/aegisub/libaegisub/common/log.cpp
+++ b/aegisub/libaegisub/common/log.cpp
@@ -26,6 +26,8 @@
 #include "libaegisub/util.h"
 
 #include <algorithm>
+#include <boost/filesystem.hpp>
+#include <boost/filesystem/fstream.hpp>
 #include <boost/range/algorithm.hpp>
 #include <cstring>
 #include <fstream>
@@ -90,43 +92,37 @@ Message::~Message() {
 	msg.freeze(false);
 }
 
-JsonEmitter::JsonEmitter(agi::fs::path const& directory, const agi::log::LogSink *log_sink)
-: time_start(util::time_log())
-, directory(directory)
-, log_sink(log_sink)
+JsonEmitter::JsonEmitter(fs::path const& directory)
+: fp(new boost::filesystem::ofstream(unique_path(directory/util::strftime("%Y-%m-%d-%H-%M-%S-%%%%%%%%.json"))))
 {
+	WriteTime("open");
 }
 
 JsonEmitter::~JsonEmitter() {
-	json::Object root;
-	json::Array &array = root["log"];
+	WriteTime("close");
+}
 
-	auto time_close = util::time_log();
+void JsonEmitter::log(SinkMessage *sm) {
+	json::Object entry;
+	entry["sec"]      = (int64_t)sm->tv.tv_sec;
+	entry["usec"]     = (int64_t)sm->tv.tv_usec;
+	entry["severity"] = sm->severity;
+	entry["section"]  = sm->section;
+	entry["file"]     = sm->file;
+	entry["func"]     = sm->func;
+	entry["line"]     = sm->line;
+	entry["message"]  = sm->message;
+	json::Writer::Write(entry, *fp);
+	fp->flush();
+}
 
-	Sink const& sink = *log_sink->GetSink();
-	for (unsigned int i=0; i < sink.size(); i++) {
-		json::Object entry;
-		entry["sec"]      = (int64_t)sink[i]->tv.tv_sec;
-		entry["usec"]     = (int64_t)sink[i]->tv.tv_usec;
-		entry["severity"] = sink[i]->severity;
-		entry["section"]  = sink[i]->section;
-		entry["file"]     = sink[i]->file;
-		entry["func"]     = sink[i]->func;
-		entry["line"]     = sink[i]->line;
-		entry["message"]  = sink[i]->message;
-
-		array.push_back(std::move(entry));
-	}
-
-	json::Array &timeval_open = root["timeval"]["open"];
-	timeval_open.push_back((int64_t)time_start.tv_sec);
-	timeval_open.push_back((int64_t)time_start.tv_usec);
-
-	json::Array &timeval_close = root["timeval"]["close"];
-	timeval_close.push_back((int64_t)time_close.tv_sec);
-	timeval_close.push_back((int64_t)time_close.tv_usec);
-
-	json::Writer::Write(root, io::Save(directory/(std::to_string(time_start.tv_sec) + ".json")).Get());
+void JsonEmitter::WriteTime(const char *key) {
+	auto time = util::time_log();
+	json::Object obj;
+	json::Array &timeval = obj[key];
+	timeval.push_back((int64_t)time.tv_sec);
+	timeval.push_back((int64_t)time.tv_usec);
+	json::Writer::Write(obj, *fp);
 }
 
 	} // namespace log
diff --git a/aegisub/libaegisub/include/libaegisub/log.h b/aegisub/libaegisub/include/libaegisub/log.h
index 4a99f2c1f..447f20063 100644
--- a/aegisub/libaegisub/include/libaegisub/log.h
+++ b/aegisub/libaegisub/include/libaegisub/log.h
@@ -19,11 +19,9 @@
 #include <libaegisub/fs_fwd.h>
 #include <libaegisub/time.h>
 
-#include <boost/filesystem/path.hpp>
-#include <cstdint>
-#include <cstdio>
 #include <ctime>
 #include <deque>
+#include <iosfwd>
 #include <memory>
 #include <vector>
 
@@ -133,26 +131,20 @@ public:
 	virtual void log(SinkMessage *sm)=0;
 };
 
-/// A simple emitter which writes the log to a file in json format when it's destroyed
+/// A simple emitter which writes the log to a file in json format
 class JsonEmitter : public Emitter {
-	/// Init time
-	timeval time_start;
+	std::unique_ptr<std::ostream> fp;
 
-	/// Directory to write the log file in
-	const agi::fs::path directory;
+	void WriteTime(const char *key);
 
-	/// Parent sink to get messages from
-	const agi::log::LogSink *log_sink;
 public:
 	/// Constructor
 	/// @param directory Directory to write the log file in
-	/// @param log_sink Parent sink to get messages from
-	JsonEmitter(agi::fs::path const& directory, const agi::log::LogSink *log_sink);
+	JsonEmitter(fs::path const& directory);
 	/// Destructor
 	~JsonEmitter();
 
-	/// No-op log function as everything is done in the destructor
-	void log(SinkMessage *) { }
+	void log(SinkMessage *);
 };
 
 /// Generates a message and submits it to the log sink.
diff --git a/aegisub/src/main.cpp b/aegisub/src/main.cpp
index 38a42d2e6..0da644497 100644
--- a/aegisub/src/main.cpp
+++ b/aegisub/src/main.cpp
@@ -180,7 +180,7 @@ bool AegisubApp::OnInit() {
 	StartupLog("Create log writer");
 	auto path_log = StandardPaths::DecodePath("?user/log/");
 	agi::fs::CreateDirectory(path_log);
-	agi::log::log->Subscribe(new agi::log::JsonEmitter(path_log, agi::log::log));
+	agi::log::log->Subscribe(new agi::log::JsonEmitter(path_log));
 	CleanCache(path_log, "*.json", 10, 100);
 
 	StartupLog("Load user configuration");
diff --git a/aegisub/tests/main.cpp b/aegisub/tests/main.cpp
index 7344b24de..87c32428f 100644
--- a/aegisub/tests/main.cpp
+++ b/aegisub/tests/main.cpp
@@ -23,7 +23,7 @@ int main(int argc, char **argv) {
 
 	int retval;
 	agi::log::log = new agi::log::LogSink;
-	agi::log::log->Subscribe(new agi::log::JsonEmitter("./", agi::log::log));
+	agi::log::log->Subscribe(new agi::log::JsonEmitter("./"));
 	::testing::InitGoogleTest(&argc, argv);
 
 	retval = RUN_ALL_TESTS();