15khz Lakka.tv?

Libretro Lakka
#1

Hi,

I recently discovered LAKKA and retroarch, and I plan to build a dedicated machine (x86, probably core2duo mini pc) for it. I already tested Lakka with liveUSB linux version, it’s working great.

I’m wondering if it’s possible to configure Lakka to start in 15khz (in low resolution like 640x288 or at worst, interlaced 640x480), so I could make a vga>scart adapter and plug the PC on a rgb scart tv.

If it’s not possible to do this, I’d appreciate to know which is the best shader for a good CRT rgb (rgb and not composite, because I know there is some shaders to emulate this specific composite ugliness look :D) emulation on LCD screen.

thank you for your help, and thanks for retroarch and lakka.

#2

I haven’t tried Lakka/XMB specifically, but I don’t imagine it would scale down to ultra-low-res very gracefully. However, the RGUI menu looks fantastic at 240p and I use it on my CGA arcade monitor all the time.

For shaders, there are a lot of options and you should just try them out and see what looks best to you. Some common favorites are crt-hyllian (without or without halation), crt-easymode, crt-geom and crt-lottes. None of these include composite emulation. Which one works best for you will also vary based on your GPU, as some are more demanding than others.

#3

thank you for your answer,

Concerning the shaders, I’ll take a look, thank you.

Concerning the 1st question, I’m not interested into mediacenter features, I just want a “frontend” for the retroarch emulators. You say that you’re using retroarch on your CGA arcade monitor, wich is basically what I want to do also (since a scart rgb tv, an old amiga rgb monitors, are, basically, arcade monitors).

For what I understand from your answer, retroarch will accept to work in 15khz (for instance, using a windows or linux with 15khz video driver or arcade video card), but I would prefer to use a dedicated gaming distro like Lakka.tv. If not, I will have to install an OS + retroarch+frontend, and configure everything to work on joypad, autostart on frontend, etc…A lot of work, sounds a bit like reinventing the wheel since Lakka just does that perfectly already. It’s just a matter of tweaking it for 15khz.

Lakka user interface with its minimalistic look and feel would look decent in low res for sure.

#4

Lakka as a distro should work fine, since it runs in KMS/EGL (that is, directly from console, no window manager, etc.). In my experience (not with Lakka specifically, mind you, but with Ubuntu), the hard part is making your OS recognize the monitor at the correct resolution and refresh rate, since old TVs/arcade monitors don’t really have EDIDs. You can create an EDID from scratch as I did here:

or you can just download the EDID I made (linked in that post), which should work for any standard CGA monitor. Note: it reports an ultra-wide 1920x240 resolution, which minimizes scaling artifacts on the horizontal axis to let you run lots of different games/systems without recalibrating the monitor for each one.

I would recommend setting up your system (switching to RGUI, etc.) on another display and then moving it to your TV/monitor for finishing touches, and make sure you have network access for ssh!

#5

thank you for your help, I will study these new informations. The “dark” part of the process for me is to “link” this 15khz EDID config inside Lakka installed system, so the “retrobox” will start in 15khz. Probably just doing it the way you explain, copying the EDID file into lib/firmware (assuming the paths are the same in an installed Lakka machine).

#6

Yeah, that’s a good question. If you need any help along the way, I’m happy to chime in when possible.

#7

thanks

for now I’m testing lakka on my lenovo laptop (core 2 duo p8700 2.8ghz), I’m searching for THE machine I’ll use for my “retrobox” (probably also a core 2 duo, in small form factor case). Then, I’ll work on the 15khz side of the project.