diff --git a/src/openrct2/rct1.c b/src/openrct2/rct1.c
index 3efc42f7a5..087dbfc049 100644
--- a/src/openrct2/rct1.c
+++ b/src/openrct2/rct1.c
@@ -21,62 +21,6 @@
 #include "util/sawyercoding.h"
 #include "util/util.h"
 
-bool rct1_read_sc4(const char *path, rct1_s4 *s4)
-{
-	uint8 *buffer, *decodedBuffer;
-	size_t length, decodedLength;
-	bool success;
-
-	if (!readentirefile(path, (void**)&buffer, &length)) {
-		gErrorType = ERROR_TYPE_FILE_LOAD;
-		gErrorStringId = STR_FILE_CONTAINS_INVALID_DATA;
-		return 0;
-	}
-
-	sint32 fileType = sawyercoding_detect_file_type(buffer, length);
-
-	decodedBuffer = malloc(sizeof(rct1_s4));
-	decodedLength = (fileType & FILE_VERSION_MASK) == FILE_VERSION_RCT1 ?
-		sawyercoding_decode_sv4(buffer, decodedBuffer, length, sizeof(rct1_s4)) :
-		sawyercoding_decode_sc4(buffer, decodedBuffer, length, sizeof(rct1_s4));
-	if (decodedLength == sizeof(rct1_s4)) {
-		memcpy(s4, decodedBuffer, sizeof(rct1_s4));
-		success = true;
-	} else {
-		success = false;
-	}
-
-	free(buffer);
-	free(decodedBuffer);
-	return success;
-}
-
-bool rct1_read_sv4(const char *path, rct1_s4 *s4)
-{
-	uint8 *buffer, *decodedBuffer;
-	size_t length, decodedLength;
-	bool success;
-
-	if (!readentirefile(path, (void**)&buffer, &length)) {
-		gErrorType = ERROR_TYPE_FILE_LOAD;
-		gErrorStringId = STR_FILE_CONTAINS_INVALID_DATA;
-		return 0;
-	}
-
-	decodedBuffer = malloc(sizeof(rct1_s4));
-	decodedLength = sawyercoding_decode_sv4(buffer, decodedBuffer, length, sizeof(rct1_s4));
-	if (decodedLength == sizeof(rct1_s4)) {
-		memcpy(s4, decodedBuffer, sizeof(rct1_s4));
-		success = true;
-	} else {
-		success = false;
-	}
-
-	free(buffer);
-	free(decodedBuffer);
-	return success;
-}
-
 bool rideTypeShouldLoseSeparateFlag(const rct_ride_entry *rideEntry)
 {
 	if (!gConfigInterface.select_by_track_type) {
diff --git a/src/openrct2/rct1.h b/src/openrct2/rct1.h
index d67e1fc677..da53723295 100644
--- a/src/openrct2/rct1.h
+++ b/src/openrct2/rct1.h
@@ -1189,10 +1189,6 @@ enum {
 
 extern const uint8 gRideCategories[0x60];
 
-bool rct1_read_sc4(const char *path, rct1_s4 *s4);
-bool rct1_read_sv4(const char *path, rct1_s4 *s4);
-void rct1_import_s4(rct1_s4 *s4);
-void rct1_fix_landscape();
 sint32 vehicle_preference_compare(uint8 rideType, const char * a, const char * b);
 bool rideTypeShouldLoseSeparateFlag(const rct_ride_entry *rideEntry);
 
diff --git a/src/openrct2/rct1/S4Importer.cpp b/src/openrct2/rct1/S4Importer.cpp
index aa840eca83..6e497d3e4f 100644
--- a/src/openrct2/rct1/S4Importer.cpp
+++ b/src/openrct2/rct1/S4Importer.cpp
@@ -14,11 +14,14 @@
  *****************************************************************************/
 #pragma endregion
 
+#include <memory>
 #include <vector>
 #include "../core/Collections.hpp"
 #include "../core/Console.hpp"
 #include "../core/Exception.hpp"
+#include "../core/FileStream.hpp"
 #include "../core/Guard.hpp"
+#include "../core/IStream.hpp"
 #include "../core/Memory.hpp"
 #include "../core/Path.hpp"
 #include "../core/String.hpp"
@@ -91,9 +94,9 @@ public:
 class S4Importer final : public IS4Importer
 {
 private:
-    const utf8 * _s4Path;
-    rct1_s4      _s4;
-    uint8        _gameVersion;
+    const utf8 * _s4Path = nullptr;
+    rct1_s4      _s4 = { 0 };
+    uint8        _gameVersion = 0;
 
     // Lists of dynamic object entries
     EntryList _rideEntries;
@@ -120,24 +123,6 @@ private:
     uint8 _researchRideTypeUsed[128];
 
 public:
-    void LoadSavedGame(const utf8 * path) override
-    {
-        if (!rct1_read_sv4(path, &_s4))
-        {
-            throw Exception("Unable to load SV4.");
-        }
-        _s4Path = path;
-    }
-
-    void LoadScenario(const utf8 * path) override
-    {
-        if (!rct1_read_sc4(path, &_s4))
-        {
-            throw Exception("Unable to load SC4.");
-        }
-        _s4Path = path;
-    }
-
     void Load(const utf8 * path) override
     {
         const utf8 * extension = Path::GetExtension(path);
@@ -155,6 +140,47 @@ public:
         }
     }
 
+    void LoadSavedGame(const utf8 * path) override
+    {
+        auto fs = FileStream(path, FILE_MODE_OPEN);
+        LoadFromStream(&fs, false);
+        _s4Path = path;
+    }
+
+    void LoadScenario(const utf8 * path) override
+    {
+        auto fs = FileStream(path, FILE_MODE_OPEN);
+        LoadFromStream(&fs, true);
+        _s4Path = path;
+    }
+
+    void LoadFromStream(IStream * stream, bool isScenario) override
+    {
+        size_t dataSize = stream->GetLength() - stream->GetPosition();
+        std::unique_ptr<uint8> data = std::unique_ptr<uint8>(stream->ReadArray<uint8>(dataSize));
+        std::unique_ptr<uint8> decodedData = std::unique_ptr<uint8>(Memory::Allocate<uint8>(sizeof(rct1_s4)));
+
+        size_t decodedSize;
+        if (isScenario)
+        {
+            decodedSize = sawyercoding_decode_sc4(data.get(), decodedData.get(), dataSize, sizeof(rct1_s4));
+        }
+        else
+        {
+            decodedSize = sawyercoding_decode_sv4(data.get(), decodedData.get(), dataSize, sizeof(rct1_s4));
+        }
+
+        if (decodedSize == sizeof(rct1_s4))
+        {
+            Memory::Copy<void>(&_s4, decodedData.get(), sizeof(rct1_s4));
+            _s4Path = "";
+        }
+        else
+        {
+            throw Exception("Unable to decode park.");
+        }
+    }
+
     void Import() override
     {
         Initialise();
diff --git a/src/openrct2/rct1/S4Importer.h b/src/openrct2/rct1/S4Importer.h
index 91d67965bb..78a7d95037 100644
--- a/src/openrct2/rct1/S4Importer.h
+++ b/src/openrct2/rct1/S4Importer.h
@@ -19,16 +19,19 @@
 #include "../common.h"
 #include "../scenario/ScenarioRepository.h"
 
+interface IStream;
+
 /**
  * Interface to import RollerCoaster Tycoon 1 scenarios (*.SC4) and saved games (*.SV4).
  */
 interface IS4Importer
 {
 public:
-    virtual ~IS4Importer() { }
+    virtual ~IS4Importer() = default;
+    virtual void Load(const utf8 * path) abstract;
     virtual void LoadSavedGame(const utf8 * path) abstract;
     virtual void LoadScenario(const utf8 * path) abstract;
-    virtual void Load(const utf8 * path) abstract;
+    virtual void LoadFromStream(IStream * stream, bool isScenario) abstract;
     virtual void Import() abstract;
     virtual bool GetDetails(scenario_index_entry * dst) abstract;
 };
diff --git a/src/openrct2/scenario/ScenarioRepository.cpp b/src/openrct2/scenario/ScenarioRepository.cpp
index c37881ec27..430ab503ac 100644
--- a/src/openrct2/scenario/ScenarioRepository.cpp
+++ b/src/openrct2/scenario/ScenarioRepository.cpp
@@ -317,12 +317,18 @@ private:
                 // RCT1 scenario
                 bool result = false;
                 IS4Importer * s4Importer = CreateS4Importer();
-                s4Importer->LoadScenario(path.c_str());
-                if (s4Importer->GetDetails(entry))
+                try
+                {
+                    s4Importer->LoadScenario(path.c_str());
+                    if (s4Importer->GetDetails(entry))
+                    {
+                        String::Set(entry->path, sizeof(entry->path), path.c_str());
+                        entry->timestamp = timestamp;
+                        result = true;
+                    }
+                }
+                catch (Exception)
                 {
-                    String::Set(entry->path, sizeof(entry->path), path.c_str());
-                    entry->timestamp = timestamp;
-                    result = true;
                 }
                 delete s4Importer;
                 return result;