Displaying emulator on Sony CRT monitor

lonestar

I set up Retropie with BBC Micro and Commodore PET and C64 emulation. I would now like to display this on a Sony PVM1371QM CRT monitor. I have purchased a HDMI to RGB converter and hooked up the Pi to the RGB and audio connections on the back but need some help setting up the HDMI output to PAL 480i resolution. Is this possible and if so, how would i go about setting this up?

I did find one reference here:

https://forums.raspberrypi.com/viewtopic.php?p=991766#p991766

However, the xrandr command does not work and just returns:

$ xrandr
Can't open display

I would like to hope that this is possible.

phillip_benoit

Your converter should handle the output to PAL. It will also specify the input settings for HDMI.

mitu

@lonestar said in Displaying emulator on Sony CRT monitor:

However, the xrandr command does not work and just returns:

$ xrandr
Can't open display

I would like to hope that this is possible.

xrandr works only when run in a desktop environment. Install the RaspiOS full image (with the desktop) and make sure you're using an X11 session (i.e. no Wayland), then you can run the commands from the RaspberryPi forums topic.

lonestar

I am not sure whether I am using Wayland. I am running Retropie which runs on Emulationstation. I don't think it uses X11 because there is no Pi desktop environment, and from Googling I see that Wayland is a replacement for X11? Does this mean I need to reconfigure Emulationstation to run on X11 somehow?
This is obviously going to be more complex than I had imagined.

mitu

@lonestar said in Displaying emulator on Sony CRT monitor:

I am not sure whether I am using Wayland. I am running Retropie which runs on Emulationstation. I don't think it uses X11 because there is no Pi desktop environment, and from Googling I see that Wayland is a replacement for X11?

Yes, if you have installed RetroPie from our image(s), then there's no desktop.

Does this mean I need to reconfigure Emulationstation to run on X11 somehow?

There's no need for a re-configuration and it's probably working from a desktop environment, but it's not a configuration we support.

lonestar

@mitu Thanks for pointing that out, yes I installed Retropie from the standard image. Yet Retropie does have some kind of GUI once Emulationstation is fired up. So if its not using Wayland or X11 and not supported on them, then what is it using and how does one configure the screen resolution?

mitu

@lonestar said in Displaying emulator on Sony CRT monitor:

So if its not using Wayland or X11 and not supported on them, then what is it using and how does one configure the screen resolution?

On the current RetroPie image you can specify the resolution using the hdmi_group and hdmi_mode options (see here), though this selects the boot video mode from the ones that the display supports. Depending on the Pi model used, you can also create a custom video mode using hdmi_cvt, but I don't think this works on a Pi4 - this is your use case, since a CRT doesn't usually have EDID/DDC information for the Pi to detect the supported video modes.

The RPI forum link has this covered, but most of the advices and options added there are created before the Pi4 and most of them don't apply to it. I'm not sure how well using X11 would work for adding custom video modes, since I haven't tried it personally, but some posters there had some success with it.

lonestar

@mitu Thank you for that link. I am using a Pi400, which I understand is essentially the same as a Pi 4, and it does have two HDMI ports. If I understand correctly, then hdmi_group and hdmi_mode should still work but hdmi_cvt will not?

Selecting the mode at boot time would be OK as I can apply the desired configuration to the second HDMI port only. I have also set up SSH to work headless should it become necessary in any case. I will experiment some with this.

lonestar

I did manage to get it working eventually, but discovered that what I though was an RGB converter was not, in fact, putting out RGB. I ended up purchasing another converter, this time for composite video (HDMI to CVBS) and using one of the BNC video ports. This worked fine with the appropriate video settings (hdmi_group and hdmi_mode) in added in config.txt. The adapter does not work with 576i, but does recognize 576p. Possibly because this is a video monitor, the image does not fill the display like on a TV - there is a black border - but it does work.