diff --git a/src/hardware/r_opengl/r_opengl.c b/src/hardware/r_opengl/r_opengl.c
index ed60f2175..73f6a4044 100644
--- a/src/hardware/r_opengl/r_opengl.c
+++ b/src/hardware/r_opengl/r_opengl.c
@@ -1924,7 +1924,7 @@ EXPORT void HWRAPI(CreateModelVBOs) (model_t *model)
 	}
 }
 
-#define BUFFER_OFFSET(i) ((char*)NULL + (i))
+#define BUFFER_OFFSET(i) ((void*)(i))
 
 static void DrawModelEx(model_t *model, INT32 frameIndex, INT32 duration, INT32 tics, INT32 nextFrameIndex, FTransform *pos, float scale, UINT8 flipped, UINT8 *color)
 {
diff --git a/src/sdl/mixer_sound.c b/src/sdl/mixer_sound.c
index 9a713608c..5a086880a 100644
--- a/src/sdl/mixer_sound.c
+++ b/src/sdl/mixer_sound.c
@@ -880,13 +880,18 @@ boolean I_SetSongSpeed(float speed)
 #ifdef HAVE_OPENMPT
 	if (openmpt_mhandle)
 	{
-		char modspd[13];
-
 		if (speed > 4.0f)
 			speed = 4.0f; // Limit this to 4x to prevent crashing, stupid fix but... ~SteelT 27/9/19
-
-		sprintf(modspd, "%g", speed);
-		openmpt_module_ctl_set(openmpt_mhandle, "play.tempo_factor", modspd);
+#if OPENMPT_API_VERSION_MAJOR < 1 && OPENMPT_API_VERSION_MINOR < 5
+		{
+			// deprecated in 0.5.0
+			char modspd[13];
+			sprintf(modspd, "%g", speed);
+			openmpt_module_ctl_set(openmpt_mhandle, "play.tempo_factor", modspd);
+		}
+#else
+		openmpt_module_ctl_set_floatingpoint(openmpt_mhandle, "play.tempo_factor", (double)speed);
+#endif
 		return true;
 	}
 #else