UI: Check pointer before the first dereference

UI/window-basic-settings.cpp

@@ -4185,6 +4185,9 @@ void OBSBasicSettings::AdvReplayBufferChanged()
 	int vbitrate = (int)obs_data_get_int(settings, "bitrate");
 	const char *rateControl = obs_data_get_string(settings, "rate_control");
 
+	if (!rateControl)
+		rateControl = "";
+
 	bool lossless = strcmp(rateControl, "lossless") == 0 ||
 			ui->advOutRecType->currentIndex() == 1;
 	bool replayBufferEnabled = ui->advReplayBuf->isChecked();
@@ -4210,9 +4213,6 @@ void OBSBasicSettings::AdvReplayBufferChanged()
 	if (memMB < 1)
 		memMB = 1;
 
-	if (!rateControl)
-		rateControl = "";
-
 	bool varRateControl = (astrcmpi(rateControl, "CBR") == 0 ||
 	                       astrcmpi(rateControl, "VBR") == 0 ||
 	                       astrcmpi(rateControl, "ABR") == 0);