diff --git a/src/face-tracker-monitor.cpp b/src/face-tracker-monitor.cpp
index 241c445..3bbceaf 100644
--- a/src/face-tracker-monitor.cpp
+++ b/src/face-tracker-monitor.cpp
@@ -1,6 +1,7 @@
 #include <obs-module.h>
 #include <obs.hpp>
 #include "plugin-macros.generated.h"
+#include "helper.hpp"
 
 
 #define MAX_ERROR 2
@@ -205,15 +206,12 @@ static uint32_t ftmon_get_width(void *data)
 		if (!ph)
 			return 0;
 
-		calldata_t cd = {0};
+		CALLDATA_FIXED_DECL(cd, 128);
 		if (proc_handler_call(ph, "get_target_size", &cd)) {
 			long long ret;
-			if (calldata_get_int(&cd, "width", &ret)) {
-				calldata_free(&cd);
-				return (int32_t)ret;
-			}
+			if (calldata_get_int(&cd, "width", &ret))
+				return (uint32_t)ret;
 		}
-		calldata_free(&cd);
 	}
 
 	OBSSource source(get_source(s));
@@ -235,15 +233,12 @@ static uint32_t ftmon_get_height(void *data)
 		if (!ph)
 			return 0;
 
-		calldata_t cd = {0};
+		CALLDATA_FIXED_DECL(cd, 128);
 		if (proc_handler_call(ph, "get_target_size", &cd)) {
 			long long ret;
-			if (calldata_get_int(&cd, "height", &ret)) {
-				calldata_free(&cd);
-				return (int32_t)ret;
-			}
+			if (calldata_get_int(&cd, "height", &ret))
+				return (uint32_t)ret;
 		}
-		calldata_free(&cd);
 	}
 
 	OBSSource source(get_source(s));
@@ -266,7 +261,7 @@ static void ftmon_video_render(void *data, gs_effect_t *)
 	if (!ph)
 		return;
 
-	calldata_t cd = {0};
+	CALLDATA_FIXED_DECL(cd, 128);
 	calldata_set_bool(&cd, "notrack", s->notrack);
 
 	if (!s->nosource) {
@@ -281,8 +276,6 @@ static void ftmon_video_render(void *data, gs_effect_t *)
 		calldata_set_bool(&cd, "landmark_only", true);
 
 	proc_handler_call(ph, "render_info", &cd);
-
-	calldata_free(&cd);
 }
 
 extern "C"
diff --git a/src/helper.hpp b/src/helper.hpp
index f939362..0e48b1e 100644
--- a/src/helper.hpp
+++ b/src/helper.hpp
@@ -8,6 +8,8 @@
 #define DEBUG_DATA_PATH_FILTER "Data Files (*.dat);;TSV Files (*.tsv);;All Files (*.*)"
 #endif
 
+#define CALLDATA_FIXED_DECL(cd, size) calldata_t cd; uint8_t calldata_##cd##_stack[128]; calldata_init_fixed(&cd, calldata_##cd##_stack, sizeof(calldata_##cd##_stack));
+
 struct pointf_s
 {
 	float x;
diff --git a/src/obsptz-backend.cpp b/src/obsptz-backend.cpp
index aa4c602..b7534dc 100644
--- a/src/obsptz-backend.cpp
+++ b/src/obsptz-backend.cpp
@@ -3,6 +3,7 @@
 #include <algorithm>
 #include "plugin-macros.generated.h"
 #include "obsptz-backend.hpp"
+#include "helper.hpp"
 
 #define debug(...) blog(LOG_INFO, __VA_ARGS__)
 
@@ -43,10 +44,9 @@ proc_handler_t *obsptz_backend::get_ptz_ph()
 	if (!ph)
 		return NULL;
 
-	calldata_t cd = {0};
+	CALLDATA_FIXED_DECL(cd, 128);
 	proc_handler_call(ph, "ptz_get_proc_handler", &cd);
 	calldata_get_ptr(&cd, "return", &ptz_ph);
-	calldata_free(&cd);
 
 	return ptz_ph;
 }
@@ -62,7 +62,7 @@ void obsptz_backend::set_pantilt_speed(int pan, int tilt)
 		same_pantilt_cnt = 0;
 	}
 
-	calldata_t cd = {0};
+	CALLDATA_FIXED_DECL(cd, 128);
 	calldata_set_int(&cd, "device_id", device_id);
 	calldata_set_float(&cd, "pan", pan / 24.0f);
 	calldata_set_float(&cd, "tilt", -tilt / 20.0f);
@@ -74,7 +74,6 @@ void obsptz_backend::set_pantilt_speed(int pan, int tilt)
 		ph = obs_get_proc_handler();
 		proc_handler_call(ph, "ptz_pantilt", &cd);
 	}
-	calldata_free(&cd);
 	uint64_t ns = os_gettime_ns();
 	available_ns = std::max(available_ns, ns) + (60*1000*1000);
 	prev_pan = pan;
@@ -96,12 +95,11 @@ void obsptz_backend::set_zoom_speed(int zoom)
 	if (!ph)
 		return;
 
-	calldata_t cd = {0};
+	CALLDATA_FIXED_DECL(cd, 128);
 	calldata_set_int(&cd, "device_id", device_id);
 	calldata_set_float(&cd, "zoom", -zoom / 7.0f);
 	proc_handler_call(ph, "ptz_move_continuous", &cd);
 
-	calldata_free(&cd);
 	uint64_t ns = os_gettime_ns();
 	available_ns = std::max(available_ns, ns) + (60*1000*1000);
 	prev_zoom = zoom;