Add libpath argument.

src/builtins/builtins-encoder.cc

@@ -27,6 +27,8 @@ BUILTIN(InitEncodeContext) {
     Handle<Object> bitrate = args.atOrUndefined(isolate, 4);
     // Framerate
     Handle<Object> framerate = args.atOrUndefined(isolate, 5);
+    // Libav Path, Optional
+    Handle<Object> libpath = args.atOrUndefined(isolate, 6);
 
     // Maybe an Encoder already exists.
     if (inited) return *isolate->factory()->ToBoolean(true);
@@ -39,8 +41,22 @@ BUILTIN(InitEncodeContext) {
             isolate, NewTypeError(MessageTemplate::kInvalidArgument));
     }
 
+    // Libav path
+    std::string libpath_cppstr;
+    if (libpath->IsUndefined()) {
+        libpath_cppstr = "";
+    } else {
+        Handle<String> libpath_str;
+        ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+            isolate, libpath_str, Object::ToString(isolate, libpath));
+        libpath_cppstr = libpath_str->ToCString().get();
+    }
+
     // Convert to C/C++ type
-    std::string outpath { Object::ToString(isolate, path)->ToCString().get() };
+    Handle<String> path_str;
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, path_str,
+                                       Object::ToString(isolate, path));
+    std::string outpath = { path_str->ToCString().get() };
 
     uint32_t width_int, height_int, bitrate_int, framerate_int;
 
@@ -50,7 +66,7 @@ BUILTIN(InitEncodeContext) {
     framerate->ToUint32(&framerate_int);
 
     enc = new LAIPIC_ENCODER::Encoder {
-        "", outpath, width_int, width_int, bitrate_int };
+        libpath_cppstr, outpath, width_int, height_int, bitrate_int };
 
     if (!enc->isReady()) {
         // Fail to initialize LAIPIC_ENCODER::Encoder.
@@ -69,6 +85,12 @@ BUILTIN(Encode) {
 
     if (!inited) return *isolate->factory()->ToBoolean(false);
 
+    Handle<Object> frame = args.atOrUndefined(isolate, 1);
+    if (frame->IsNull()) {
+        enc->encodeRGB(nullptr, 0);
+        return *isolate->factory()->ToBoolean(true);
+    }
+
     Handle<JSTypedArray> array;
     ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, array,
         JSTypedArray::Validate(isolate, args.atOrUndefined(isolate, 1), "ENCODER.encode()"));

src/init/bootstrapper.cc

@@ -2786,12 +2786,12 @@ void Genesis::InitializeGlobal(Handle<JSGlobalObject> global_object,
     InstallToStringTag(isolate_, json_object, "JSON");
   }
 
-  {
+  { // -- E N C O D E R
     Handle<JSObject> encoder =
         factory->NewJSObject(isolate_->object_function(), AllocationType::kOld);
     JSObject::AddProperty(isolate_, global, "ENCODER", encoder, DONT_ENUM);
     SimpleInstallFunction(isolate_, encoder, "init",
-                          Builtin::kInitEncodeContext, 5, true);
+                          Builtin::kInitEncodeContext, 6, true);
     SimpleInstallFunction(isolate_, encoder, "encode",
                           Builtin::kEncode, 1, true);
     SimpleInstallFunction(isolate_, encoder, "close",