RetroArch - Native CRT Support

Alphanu · 21 June 2018 22:23

The first issue you will have is windows. Especially with a Nvidia card!

My first question is. How have/are you creating the resolution mode-line?

With windows you really need to use a AMD 5xxx or higher with CRTemudriver.

With Linux there is less of a restriction. I has Intel GPUs working so I will assume some Nvidia cards will work too.

This only works correctly if the video card can simulate the correct video timings.

The FPS on screen display has a delay in its update. you should see a message setting refresh pop up, this is the speed that is being set by my code. Also with the current limitation of windows refresh screen hz are limited to 50, 55 or 60. I am working on this.

For all the windows users out there, I am working on a live USB so you can boot Linux RetroArch to play without having to install.

I will double check the windows code in case a bug has been introduced with the addition of Linux.

** I just read back that you are also having trouble on linux, this could be the Nvidia card. But also could be Ubuntu 18. I have only tested Ubuntu 14, 16 and Arch Linux.

I did find a VSYNC bug with Ubuntu a while back, I had to change swap frames to 2 for it to work properly, this may not be the case for you but it is worth a try.

dwhweb · 21 June 2018 22:44

Wrote a small shell script that changes the mode on boot via xrandr - if anyone else needs it, feel free to copy -

#!/bin/bash
xrandr --newmode "704x480" 13.27 704 720 784 848 480 483 489 523 interlace -hsync -vsync
xrandr --addmode VGA-1 704x480
xrandr --output VGA-1 --mode 704x480

This is invoked in ~/.config/lxsession/LXDE/autostart when LXDE loads - maybe this is not the preferred way to do this, I’m unsure.

I’m not intending using Windows if at all possible - was just asking in case Ati cards handle 15khz modes better and my hardware was struggling.

Alphanu · 21 June 2018 22:51

Thanks @dwhweb

This script is similar to what I use. Bear in mind that you may need to change “VGA-1” to your output ID wich could be VGA1 or even DVI-1 and so on. Just type xrandr in terminal and it will let you know what output is connected.

dwhweb · 23 June 2018 00:45

I’ve been messing around with this again today and seem to have got to the bottom of it – removing the Geforce GT 710 and re-enabling the onboard Radeon 4200 seems to have solved the problem. Works perfectly without the need for Vsync, Hard GPU sync or threaded video enabled. I would be interested if anyone knows why.

I was hoping I would get the Geforce working with it so initially I tried replacing the nouveau drivers with the nvidia binary blob – I would not recommend that others try this as from what I gather from https://devtalk.nvidia.com/default/topic/1008518/jetson-tx1/x11-configuration-xrandr-refresh-rates/ the official nvidia drivers only accept predefined modes or modes from a monitor EDID – xrandr won’t change modes with these drivers.

Maybe ATI cards are better suited for CRT displays in Linux as well as Windows?

astos · 9 July 2018 19:39

I’ve found that using crt switchres with super resolutions (2560) on windows 7, retroarch can’t seem to get the correct refresh rate so the game is stuttery and the sound skips. However if I use native resolution modes it runs fine. my video card is an HD5450 and groovymame works just fine with super resolutions. I don’t really mind having super resolutions for mame and native for retroarch, but I’m still curious why this would happen. My cpu is a Pentium G3258 OCed to 4.5GHZ with 8GB ram. This cpu has great single thread performance so I’m not sure what’s happening here.

Alphanu · 11 July 2018 15:40

That’s a strange one. I’ve never had sync problems. You’ll need VSYNC and audio sync turned on. It will Probably be due to the modelines you have installed. Grroveymame uses dynamic hz which Retroarch does not.

You’ll have to install static modelines. You’ll find the ones you need on the front page of the Retroarch Github.

Also Retroarch has mame with switching so you don’t need both.

OlDirty · 11 July 2018 17:48

I’m trying to enable super resolution but can’t find the super resolution settings under the \Video in Retroarch. Do i have to enable something so they show up? I have CRT Emudriver installed and GroovyMame is running fine with super resolutions.

Alphanu · 11 July 2018 20:16

You need to enable advanced settings. This can be found in user interface I believe.

Once enabled CRTSwitch will be found in video settings.

You need to make sure that you install your super resolutions in static mode not dynamic. RetroArch can do 3840, 2560 and 1920. you need to change these values within the retroarch.cfg file

mdrejhon · 20 July 2018 16:56

(EDIT: Discussion complete)

Re: $1082 BountySource on RetroArch lagless VSYNC

Question: Does the Native CRT support preserve original machine’s input latencies for mid-screen input reads too, with the CRT module implementation?

EDIT: No, it is refresh cycle granularity, not scanline granularity

(e.g. no surge-execution, no pre-rendering of framebuffer before scanning out, just 1:1 emulator execution speed while having original machine’s lag, streaming scanlines out of graphics output in realtime, aka realtime beam racing – emulator executes at 1:1 original machine speed with no surge-execution, yet is streaming pixels out in realtime, rather tham framebuffering all of them first before display?)

EDIT: The beam racing sync support can be later merged with CRT support, to achieve exact original signal with exact original-machine lag without need for pre-framebuffering).

Context:

Lagless VSYNC Support (beam raced synchronization) - [$1082 !]

I’m just trying to research commonalities.

EDIT: Done. Thanks, @Alphanu

P.S. I must compliment you in this great work in CRT support.

OlDirty · 22 July 2018 12:07

I manualy added the modes to my super resolution setup. The ones which are listed in the FAQ: 15 khz CRT documentation wiki.

Set the CRT Switch in retroarch and started a game with BigBox. I hear a switching noise from my chassis and then my screen goes black. The games run well if i connnect a LCD with the CRT Switch OFF.

purity1516 · 24 August 2018 12:20

Hello @Alphanu Let me ask if there was any progress implementing calamity 's dynamic modelines to your code.

Alphanu · 24 August 2018 18:44

I have been having a break recently. Taking some time out for family!

However, I am back now. I am still talking with calamity and it will be happening. ATM I don’t have a time scale on when this will be implemented as he is quite busy.

purity1516 · 27 August 2018 10:50

this is quite fair.
thanks for your job!

rafan · 11 September 2018 14:31

I’m trying to get the Commodore 64 core (vice_x64_libretro) to work with CRT Switchres.

I have the 2560x272@50hz resolution available on the CRT, but the core will not switch to the resolution. CRT Switchres is on and I have the aspect set to Core Provided.

Other cores I tried up until now work perfectly with CRT switchres, but this Commodore 64 seems to have some issues.

@Alphanu could you possibly take a peek to what’s going wrong with this core? (Or what I may be doing wrong )

rafan · 16 September 2018 05:52

@Alphanu

In case you missed my previous post.

Does the vice_x64_libretro core (commodore 64 core) work for you with switching under Linux?

Alphanu · 16 September 2018 15:20

I have not tested that core yet. Next time I have a run through I will give it a go.

No. I’ve been measuring the output from the PC connection with an oscilloscope. So I have re-written the way the dotclock and porches are calculated to generate the output resolution for Linux. Now the output matches the original hardware. So for cores that report the exact res and hz its almost perfect

hunterk · 17 September 2018 03:04

If you guys can list cores that don’t report exactly, we can try to fix that.

@Alphanu FYI, Twinaphex just added those menu options for you to tie into.

Alphanu · 17 September 2018 17:15

@hunterk Oh cool. I’ve had a quick look and it seems that until I change things my side, CRT switching wont work.

If i get time in the week I will get on it, otherwise it will get done at the weekend.

lkl2018 · 18 September 2018 12:54

Hello Guys !

Maybe I won’t have any answer as this discussion is already gone so fare technicaly speaking; however, I wanted to know if any tutorial existed for the retroarch CRT setup. I found videos only showing it worked (without explanation), and some forum topic, but nothing very clear. My problem is that I got a UMSA (ultimate scart adapter), an ATI card, with 15khz activated, and tried to use retroarch on my crt (advanced mode, crt switch activated so on…). However, I don’t know if I miss some modelines, or if arcade_OSD is messing with retroarch but I can’t have the UI properly scaled, for instance. I found a retroarch_2560.exe file but it didn’t work. There are also some trick to do in order to launch the menu from a LCD and emulators to the CRT I think, but I didn"t find any how-to.

that’s why I’m asking if anybody did a clear tutorial designed for people that have a PC hokked to a CRT.

thanks in advance to whoever will help

James-F · 18 September 2018 14:40

I want to know too whether there is a tutorial, much more convenient that going through 350 posts.

I have a VGA to RGB-Scart adapter that works perfectly with 15kHz resolutions from my Nvidia card, but I have to set the secondary monitor (CRT TV) to that specific resolution (1280x240) permanently.