UI: Use CQP for NVENC when using simple output mode

When using simple output mode, previously NVENC did not support a
constant quality rate control method, and you'd have to use VBR with
bitrate.  However CQP has since been added to NVENC, and it's preferable
to use for recording when available instead of using VBR.

obs/window-basic-main-outputs.cpp

@@ -154,7 +154,7 @@ struct SimpleOutput : BasicOutputHandler {
 
 	void UpdateRecordingSettings_x264_crf(int crf);
 	void UpdateRecordingSettings_qsv11(int crf);
-	void UpdateRecordingSettings_nvenc(int bitrate);
+	void UpdateRecordingSettings_nvenc(int cqp);
 	void UpdateRecordingSettings();
 	void UpdateRecordingAudioSettings();
 	virtual void Update() override;
@@ -461,12 +461,13 @@ void SimpleOutput::UpdateRecordingSettings_qsv11(int crf)
 	obs_data_release(settings);
 }
 
-void SimpleOutput::UpdateRecordingSettings_nvenc(int bitrate)
+void SimpleOutput::UpdateRecordingSettings_nvenc(int cqp)
 {
 	obs_data_t *settings = obs_data_create();
+	obs_data_set_string(settings, "rate_control", "CQP");
 	obs_data_set_string(settings, "profile", "high");
 	obs_data_set_string(settings, "preset", "hq");
-	obs_data_set_int(settings, "bitrate", bitrate);
+	obs_data_set_int(settings, "cqp", cqp);
 
 	obs_encoder_update(h264Recording, settings);
 
@@ -485,7 +486,7 @@ void SimpleOutput::UpdateRecordingSettings()
 		UpdateRecordingSettings_qsv11(crf);
 
 	} else if (videoEncoder == SIMPLE_ENCODER_NVENC) {
-		UpdateRecordingSettings_nvenc(ultra_hq ? 90000 : 22000);
+		UpdateRecordingSettings_nvenc(crf);
 	}
 }