240p via HDMI on Raspberry Pi to RGBS, no need for RGB hats!

[fernan1234]

Though it is worth noting again that without super resolutions integer scale while solving any scrolling shimmering issues is effectively limited to 2x horizontal, which will be too skinny for some game resolutions.

I swear that this whole mess is 1000% easier if you just use RetroArch instead of messing with Retropie. RA let's you lock integer scaling from the video settings menu and all of your settings are controlled in one place. (outside of the config.txt)

Never was a fan of Retropie. I'd rather use Lakka instead, if I were not comfortable enough already with my Recalbox setup.

[setiawan]

Can anyone recommend a HDMI -> VGA converter? Should I get a powered/active one? Does that matter at all? Otherwise, there are a ton of options on ebay, and it feels like if I make an unguided decision, I'll end up choosing that one that just so happens to not work for whatever reason.

I'll be hooking it up with a JVC TM-H150CG, so the chain will go rpi4b -> HDMI to VGA converter -> VGA to RGBHV BNC cable -> JVC RGBHV input.

[vol.2]

Never was a fan of Retropie. I'd rather use Lakka instead, if I were not comfortable enough already with my Recalbox setup.

Support for Lakka on the pi has never been great. There are many bugs and incompatibilities with various cores, and I get the impression that it's too much work to maintain a pi-exclusive version of Lakka when there is already a generalized armhf version of Retroarch that basically works on all armhf devices.

With the recent efforts to unlock the performance potential on the pi, you can now compile RetroArch on the Pi4 for GLES3 instead of videocore, and there is talk of getting EGL to run (which can run without X11), but it's not been worked out yet (and the cores haven't been compiled for EGL). The cores are compiled for GLES3, notably mupen (which is the only compiled version for armhf RA that I can find)

Can anyone recommend a HDMI -> VGA converter?

I have a Portta and Tendak. Both of them work fine, but some of the Tendak's are better than others. Read through this thread, it will give you the information you seek viewtopic.php?f=6&t=59860&start=150

[kitty666cats]

Portta all the way!!!

[Fudoh]

I swear that this whole mess is 1000% easier if you just use RetroArch instead of messing with Retropie. RA let's you lock integer scaling from the video settings menu and all of your settings are controlled in one place. (outside of the config.txt)

if Retroarch can do it, then Retropie can do it as well. The base is the same. Care you post one of your retroarch.cfg files ? Or just the resolution part.

If you lock RA to integer scaling as you mentioned, does it correctly adapt to systems that has games running in more than a single horizontal resolution ?

@fernan1234:

This is not the case if you use integer scaling.

I know, but isn't 512px an awfully low horizontal fill factor? I'm pretty sure some monitors won't even be able to stretch that to reach both sides of the active picture area.

Did my first test with a small BVM today. CEA-8, 660px viewport. bilinear filter on the horizontal. Looks REALLY good. I'll try to take some photos over the next days.

[fernan1234]

I know, but isn't 512px an awfully low horizontal fill factor? I'm pretty sure some monitors won't even be able to stretch that to reach both sides of the active picture area.

Yes that is correct. I think I mentioned a while ago that those games are an issue. My workaround is to turn on the 16:9 mode on my BVM, which stretches the picture close enough to what it would be originally (and this display mode itself can be further adjusted as needed on the monitor side). With other CRTs it may not be as practical to accommodate for this limitation though. As I said earlier, using a super resolution is generally more convenient except for some cores where it causes problems (and which happened to be the ones I used to use more often), at least in my experience.

[Fudoh]

Is there a go-to low-cost sync combiner option available for somebody you wants to connect a Pi/HDMI/DAC setup to a RGsB or RGBs compatible monitor or TV, but not a RGBHV compatible one? I would recommend any of the cheap Extron interfaces, but it's large and cabling can easily get cluttered this way.

I know that at this point something like a RGB-Pi Scart cable makes more sense, but that's not always an option.

[fernan1234]

I know that at this point something like a RGB-Pi Scart cable makes more sense, but that's not always an option.

That's actually not a good solution since, first, AFAIK it limits you to using one of their images, and second and IMO more importantly, it's GPIO-based which means no 480i/240p but only 240p.

A messy Extron RGB interface setup is worth it for RGBs/RGsB-only monitors. The older and simpler ones are found for very cheap (while the fancier ones with multiple inputs and displays have become pretty expensive). There's also this DIY approach for sync combining: https://www.retrorgb.com/building-a-pas ... biner.html

[vol.2]

if Retroarch can do it, then Retropie can do it as well. The base is the same. Care you post one of your retroarch.cfg files ? Or just the resolution part.

It can (more or less), but the process is convoluted by the settings being spread out. You can also bypass the RP settings and just set things in the RA config, but there is a trick to getting it to save without being reset by RP each time you boot (because it interferes with the way that RP controls RA's settings)

I say "more or less" because RP is not running the latest and greatest RA, nor does it incorporate all the features at parity. I can't say exactly what options you exactly will have in RP (even in RA in RP).

If you lock RA to integer scaling as you mentioned, does it correctly adapt to systems that has games running in more than a single horizontal resolution ?

Yes. Here's a Genesis and 256 SNES game. Notice the menu text is messed up in the genesis game because it's altered the resolution:

Spoiler

Spoiler

And here's what I set my console to, but that doesn't really matter because it will change the moment a game is loaded, the default resolution is just for the console.

Spoiler

-All you have to do is open the game and tweak the video settings as you looking at the screen and you can adjust it in real-time, switching in and out of the game as you go. You don't have to exit out of it and restart or anything. Then once you have things the way you like it, you go to QuickMenu (which only appears when a game is running), and then to Overrides. You select "Save Game Overrides," and it saves the profile for that game. You can also save the overrides for the all games on a core, or for all games in the same directory (if you have a bunch of games with a similar profile).



This is all with the retrotink using a base resolution for the system of 3840x240. There's going to be a lot of crap in there that I don't use like "windowed resolution' settings and the like:

Spoiler

video_adaptive_vsync = "false"
video_allow_rotate = "true"
video_aspect_ratio = "-1.000000"
video_aspect_ratio_auto = "false"
video_black_frame_insertion = "false"
video_context_driver = ""
video_crop_overscan = "false"
video_ctx_scaling = "false"
video_disable_composition = "false"
video_driver = "gl"
video_filter = ""
video_filter_dir = "default"
video_font_enable = "true"
video_font_path = ""
video_font_size = "52.000000"
video_force_aspect = "true"
video_force_srgb_disable = "false"
video_frame_delay = "0"
video_fullscreen = "false"
video_fullscreen_x = "0"
video_fullscreen_y = "0"
video_gpu_record = "false"
video_gpu_screenshot = "true"
video_hard_sync = "false"
video_hard_sync_frames = "1"
video_layout_directory = "~/.config/retroarch/layouts"
video_layout_enable = "true"
video_layout_path = ""
video_layout_selected_view = "0"
video_max_swapchain_images = "3"
video_message_color = "ffff00"
video_message_pos_x = "0.200000"
video_message_pos_y = "0.050000"
video_monitor_index = "0"
video_msg_bgcolor_blue = "0"
video_msg_bgcolor_enable = "false"
video_msg_bgcolor_green = "0"
video_msg_bgcolor_opacity = "1.000000"
video_msg_bgcolor_red = "0"
video_post_filter_record = "false"
video_record_config = ""
video_record_quality = "4"
video_record_scale_factor = "1"
video_record_threads = "2"
video_refresh_rate = "60.056454"
video_rotation = "0"
video_scale = "3.000000"
video_scale_integer = "false"
video_shader_delay = "0"
video_shader_dir = "~/.config/retroarch/shaders"
video_shader_enable = "false"
video_shader_watch_files = "false"
video_shared_context = "false"
video_smooth = "false"
video_stream_config = ""
video_stream_port = "56400"
video_stream_quality = "10"
video_stream_scale_factor = "1"
video_stream_url = ""
video_swap_interval = "1"
video_threaded = "false"
video_vsync = "true"
video_window_opacity = "100"
video_window_save_positions = "false"
video_window_show_decorations = "true"
video_windowed_fullscreen = "true"
video_windowed_position_height = "720"
video_windowed_position_width = "1280"
video_windowed_position_x = "0"
video_windowed_position_y = "0"

And this is the config.txt for that:

Spoiler

[pi4]
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
dtoverlay=vc4-fkms-v3d
max_framebuffers=1


######RetrotinkUltimate#####


dtoverlay=dpi24
enable_dpi_lcd=1
display_default_lcd=1
dpi_output_format=519
dpi_group=2
dpi_mode=87

dpi_timings=3840 1 109 343 343 240 1 3 5 14 0 0 0 60 0 72925291 1

As for the sync combiner, there used to be a real bad-ass solution that I got one of awhile back that's just a BNC breakout board with a sync combiner chip on it, but I can't find it on ebay anymore. I saw the retrotink VGA-SCart boards that mike opensourced, those are only $30 and here:

https://www.ebay.co.uk/itm/VGA2SCART-VG ... 4363618169

[kitty666cats]

Another idea (not at all optimal) dawned on me - right this second, I'm downscaling to 240p using GBS Control with an image set to CEA 480p, lol. Obviously, this is not what people should be aiming to do though

[Fudoh]

Thanks for the detailed reply, vol.2!

I saw the retrotink VGA-SCart boards that mike opensourced, those are only $30 and here:

nice, I'll try one of those. Arcadeforge's UMSA costs about the same. That's probably a good alternative for local users over here.

[vol.2]

Arcadeforge's UMSA costs about the same. That's probably a good alternative for local users over here.

the ebay one sells as a board-level item for a little cheaper, 19 lbs.

[kitty666cats]

UMSA is definitely a better bet if you can get it for around the same price, or of course an Extron interface is always great

[Fudoh]

UMSA is definitely a better bet if you can get it for around the same price

why? I trust Mike's designs. The UMSA requires an external PSU, while Mike's converter design is powered through a 5V line on the VGA input. If this works, it might be an easier setup. Anyway, I ordered both and will give them a try with the Pi's 240p output.

[NewSchoolBoxer]

why? I trust Mike's designs. The UMSA requires an external PSU, while Mike's converter design is powered through a 5V line on the VGA input. If this works, it might be an easier setup. Anyway, I ordered both and will give them a try with the Pi's 240p output.

Is pulling 5V from VGA pin 9 not a worse design? For powering the EDID or DDC chip inside a monitor but can assume using here is no issue. Issue is HDMI 5V line is limited to 50 mA and VGA is supposed to allow up to 1A but older standard was 50 mA max. I don't think a guarantee that every HDMI to VGA converter is suppling more power to pin 9 to get up to 1A, especially in this world of do it yourself retro tech or race-to-the-bottom priced no brand electronics. https://electronics.stackexchange.com/q ... -connector

5V*50 mA DC is 0.25 watts. Depending on what you're powering, that could be fine or nowhere near enough. USB 1.0 guaranteed current is 500 mA, therefore 2.5W, and with the rise of hungry cell phone batteries, USB power can be 5W or more.

USMA may have higher power needs than Mike's device or may have other reason for wanting external power. Electromagnetic interference is going to be higher on the VGA line than it is from an external power source.

[vol.2]

The SN74HCS7266 on the VGA2SCART takes about 0.1ua typical. You could power it with a potato, one of those small round, red guys.

[Fudoh]

Both VGA to Scart adapters (from Retro Upgrades in the UK and from Arcadeforge in Germany) work perfectly.

One small tiny detail I can't work out though: when I set my Pi to boot in 480i (hdmi mode 6), Emulationstation assumes a 16:9 ratio, so everything looks a bit horizontally squeezed on a 4:3 screen. On a XGA display with the Pi set to output XGA as well, ES properly assumes a 4:3 display and displays accordingly.

Any idea how I can get ES to honor the 4:3 ratio during 480i output ?

[fernan1234]

This may be of interest to people following this topic:

https://www.libretro.com/index.php/retr ... dmap-q1q2/

Basically those who already have a DE10 Nano for a MiSTer setup or some other purpose will be able to use it for Retroarch. Should feel beefier than a Pi eventually, and 15khz output via HDMI, or the analogue IO board, should be supported just as it is on MiSTer.

Of course, the Nano is much more expensive than a Pi so it probably won't be a good solution for those who like the Pi precisely for its low cost.

[vol.2]

Both VGA to Scart adapters (from Retro Upgrades in the UK and from Arcadeforge in Germany) work perfectly.

One small tiny detail I can't work out though: when I set my Pi to boot in 480i (hdmi mode 6), Emulationstation assumes a 16:9 ratio, so everything looks a bit horizontally squeezed on a 4:3 screen. On a XGA display with the Pi set to output XGA as well, ES properly assumes a 4:3 display and displays accordingly.

Any idea how I can get ES to honor the 4:3 ratio during 480i output ?

I had a problem with my pi in the past where I couldn't get it to output in 4:3. I'm not sure if it's the same as yours though.

The first thing to check (assuming you haven't) is if you can get a 4:3 image when using a progressive mode. If you can, then your problem is not the same as mine, and it's most likely something specific to ES and I wouldn't be able to help.

If progressive modes also appear as squished 16:9, then it might be a firmware issue. That's exactly the reason that I stopped using the pi with a HDMI-VGA adapter so long ago. If you can't get progressive modes to work correctly, you can read below to troubleshoot, otherwise just ignore it.

Spoiler

There should be a call in the config.txt that expresses which blob to use for controlling the DRM/KMS graphics rendering pipeline. I don't have a Pi3, so I'm not sure if they ever figured out how to enable real KMS for that, when I was using one, it was FKMS or Legacy still.

Legacy is the Broadcom driver that they provided to run the GPU on the VC4. FKMS is a proprietary blob that the Pi foundation developed with the aid of Broadcom under strict NDA as a stop-gap measure for tailoring the VC4 to the Pi's particular breed of hardware and software. Only thing is that it took almost 10 years to get over the gap. Recently (end of last year) they finally got the VC6 on the Pi4 (and possibly the VC4 on the Pi3) to play nice with plain old regular KMS from the Linux kernel.

That was the issue that I ran into with the aspect ratio way back when.

Basically, I had to switch around dtoverlay=vc4-fkms-v3d. Try to find that in your config.txt. If it's there, comment it out and try again. If it's not, try to add it. If there is some other entry that calls "regular" KMS (it will not have a "k"), you can't use both switches. It will use whichever of them is last in the config.

There was another time that I had some overclocking issues that screwed it up. You can also try disabling all overclocking as a troubleshooting step.

None of this should be relevant if you have a correct aspect ratio on progressive resolutions.

[vol.2]

Of course, the Nano is much more expensive than a Pi so it probably won't be a good solution for those who like the Pi precisely for its low cost.

Yeah, that looks really cool. It's definitely expensive though. I seriously thought about mister before, but with all the dedicated hardware and piecing things together little by little, it seemed to be too much. It's interesting that it's using an FPGA to emulate the systems (that's really the "big" selling point), but I know that I personally wouldn't notice a difference between RA on a Pi and RA on a Mister. For ease of setup, a cheaply purchased secondhand PC running CRT emudriver and an older ATI card is also a great solution and much higher horsepower than all of the above.

But interesting to note that it will support RA. I will definitely keep my eye on that. Thanks.

[Fudoh]

slightly OT, but while we're at it: could somebody with Retropie running on a Pi3 get me a copy of this folder (after adding the core using the web updater), please? The core is officially supported, but no longer included by default. And I don't seem to be able to find a binary download for it.

Code: Select all

/opt/retropie/libretrocores/lr-fbalpha2012

My Pi setup is currently not LAN or WLAN capable. And as far as I can tell there are a few NG games that don't run on FBNeo, but only on Alpha2012 - no matter which rom versions are used.

[vol.2]

I can't help with the FB Alpha 2012 binary, but I thought you could just use MAME if FB NEO won't work. That's worked for me in the past. I think I was using MAME 2002 for stuff with compatibility issues.

I tried to compile FB Alpha for RA with no success awhile back because FB Neo is basically the same thing but newer and the developer is *extremely* hostile to requests pertaining to Alpha if I remember correctly. So be careful FWIW.

Ok, now looking it up...

Ah yes, there is some drama behind the issues that I forgot about it. Tread lightly poking around for help.

https://www.retrorgb.com/final-burn-neo ... alpha.html

[Fudoh]

thanks for the pointer. And my bad - turned out to be a bios file mixup. Didn't realize something changed there as well between my older FBA set and the now required FBneo one.

[vol.2]

I've made an interesting discovery that may account for some issues I was seeing on the Pi4 with HDMI-VGA adapters and custom modeline.

The HDMI pipeline on the Pi4 pushes 2 pixels per clock cycle. Apparently, this means that all horizontal resolutions must contain only even integers for all values. The behavior if it finds an odd number is to fall back to the closest lower resolution in the modedb pool. If no lower resolution is available, then it chooses the lowest higher resolution.


I wondered why this would be an issue if you were to, for example, have and odd value for both the front and back porch, but I haven't got an answer on that yet.

https://www.raspberrypi.org/documentati ... i4-hdmi.md

IAC, if you are trying to create arbitrary resolutions out of the HDMI hole on a Pi4, it's worth paying attention to this factor.

[Fudoh]

after using various converters to get an analogue 240p signal from my Pi, I wanted to share my findings - possible to make the choice easier for anybody who wants to try this.

- Startech HDMI to VGA (actually VGA or component)
https://www.startech.com/en-de/audio-vi ... s/hdmi2vga
Works like a charm both in RGB and component. Works well with full range RGB HDMI output (which is my prefered setting). It's a powered DA converter, so one more PSU. High official price ($250?), but I got it cheap ($35) from ebay.

- Portta HDMI to VGA converter
https://www.amazon.de/-/en/gp/product/B003O55U8K
Works great with full range RGB HDMI output. It's an externally powered DA converter (with an annoyingly small DC barrel connector), so one more PSU. Retails for under $30 new on Amazon.

- Portta HDMI to YUV converter
https://www.amazon.com/gp/product/B00A8FIQXA
Works great with full range RGB HDMI output. It's an externally powered DA converter (with an annoyingly small DC barrel connector), so one more PSU. Retails for under $20 new on Amazon.

- Generic HDMI to YUV Converter with rounded top without branding
https://www.ebay.de/itm/264962656193
Always outputs rubbish when the Pi boots in 480i. Starting a game blindly (into 240p) makes it come alive. Exiting back into Emulationstation (480i) works fine afterwards. Otherwise flawless quality. Works great with full range RGB HDMI output. It's an externally powered DA converter, so one more PSU. Retails for about $15-20 on ebay (from chinese sellers)

- Generic HDMI to YUV Converter with rounded top and with "HD Video Converter" branding on top.
https://www.ebay.de/itm/353359161260
Didn't work for me in 480i or 240. Works in 480p though, so at least it doesn't seem to be defective.

- LogiLink HDMI to YUV breakout box
https://www.ebay.de/itm/265012724614
Works in 480i, but refuses to play along in 240p. Was $30 new on ebay.

- Speaka HDMI to YUV converter
https://www.amazon.de/dp/B00L925G0M (and certainly available from other brands as well)
Works in 480i, but refuses to play along in 240p. Was $30 new on ebay.

- Tendak HDMI to VGA
https://www.amazon.de/-/en/gp/product/B06WCZDDY1
Works with full range RGB HDMI output. It's a HDMI-powered DA converter, so no extra PSU. Retails for $15 new on Amazon. Has audio output. Sometimes I got some sparkles in the image on the initial boot. Was usually fine after booting into game.

- Snowkids HDMI to VGA cable
https://www.amazon.de/-/en/gp/product/B08CW57STX
Requires the HDMI output to be set to LIMITED range RGB. It's a HDMI-powered DA converter, so no extra PSU. Retails for $13 on Amazon, available in various cable lengths, which is nice. Quite neat, but it does not have its own audio output, so audio must be taken from the Pi directly or using a HDMI extractor.


INCOMING for testing: Extron DVI-RGB 200 converter


For RGBHV to RGBs conversion I used:

- Extron 580xi RGB interface (or any other of their RGB interfaces)
https://www.extron.com/product/rgb580xi
Obviously fine, but huge, requires space and power. BNC outputs. Nothing easy for a small setup.

- Arcadeforce UMSA
http://arcadeforge.net/UMSA:::15.html
Works great. From 30 EUR directly from Arcadeforge Germany. Requires its own PSU.

- VGA2Scart based on Mike Chi's Design.
https://www.retroupgrades.co.uk/
Works great. 20-25 GPB (with or without 3D printed cover) directly from retroupgrades UK. Requires no additional PSU.
UPDATE: The VGA2Scart has problems providing the correct blanking voltage for TVs that require a "RGB switching signal". If you have a TV or monitor that you can manually set to RGB, then this converter will work fine. If not, then get the UMSA instead.

I am not the greatest audiophile. The Pi's audio output is supposed to be pretty bad, but I have a hard time hearing great differences between a 50 cent D/A converter built into any of those converters above and the Pi's own 3.5mm analogue output. If you want to go audiophile, you can use a HDMI audio extractor and better audio DAC, but I would say, sticking to the Pi's 3,5mm output is alright for classic gaming, at least compared to the converters above.

(TESTING SOON: HDMI audio extractor + DACMagic + Marshall speaker)

My recommendation for any permanent setup are the Portta converters. Reliable, absolutely fine PQ during my tests. Easy to get and rather affordable. The component version for $20 can directly be used with any 15khz-YUV capable monitor or TV. If RGB is required on the TV's end, all the tested solutions are fine. For a permanent PVM or BVM I would use an Extron (and directly convert to RGsB instead of RGBs). If you need to integrate into a Scart environment the other two sync converter solutions (UMSA and VGA2Scart unit) are great, since they give you necessary signaling on pins 8 and 16 of the scart connector, which some TV require to enable RGB.

The slightly cheaper generic chinese boxes are hit or miss and I don't think saving $5 over the Portta converter is worth it. You can get lucky, but it's a risk. One of mine was a dud and the other has problems with the Pi's initial 480i boot-up. Most other boxes I tested didn't work out for me and the Startech is way to expensive to get a recommendation.

One the easiest solutions all around was actually the Snowkids cable along with the VGA2Scart, since both are passively powered, so there's absolutely no extra PSU required between the Pi's HDMI output and a CRT's Scart input. I would definitely prefer it to the Tendak. it's way more solid and had no sparkles on my setup. It just requires the Pi to be set to limited range though (which is a simple setting in the Pi's config.txt file).

I'll update once I get more converters.

[vol.2]

The Pi's audio output is supposed to be pretty bad, but I have a hard time hearing great differences between a 50 cent D/A converter built into any of those converters above and the Pi's own 3.5mm analogue output.

Thanks for posting all your results.

In terms of audio, I found that a cheap-o usb audio DAC is a good move. The issue comes when you are dealing with source material with marginal audio fidelity, it will compound the issue to use the built-in DAC. Additionally, there is grounding problems with the 3.5mm jack on some setups, and you may find it to be completely unusable in that case.

However, you are unlikely to notice much of a difference unless you have a suitably good amp and speakers anyway. The quality of your audio is only as good as the worst component in the chain.

[fernan1234]

I'd strongly recommend extracting the digital audio from the HDMI output in one of these setups, rather than rely on whatever the video DAC happens to include. Being able to get clean digital audio is one of the big advantages of going the HDMI route for this.

[vol.2]

I'd strongly recommend extracting the digital audio from the HDMI output in one of these setups, rather than rely on whatever the video DAC happens to include. Being able to get clean digital audio is one of the big advantages of going the HDMI route for this.

The HMDI holes are no better than the USB holes. It's all digital; I just don't have any receivers with HDMI input, but I have good pro audio USB interfaces.

[Fudoh]

Yeah, I guess. On my permanent setup I'm using an HDMI audio extractor and take it from there.

I just pointed it out, since using certain converters didn't require any additional PSUs, so of course it seems like the easiest way to just use the 3.5mm audio connector on the Pi itself.

USB audio doesn't sound to bad either. I think I have a Cambridge DACMagic unit somewhere which I don't use for anything else atm.

[kitty666cats]

I’ve been quite happy with the 3.5mm analog audio output of the Portta HDMI to VGA, I definitely prefer it over the Pi’s 3.5mm jack.

I wonder if the fact that the Pi’s 3.5mm isn’t solely dedicated to audio (outputs composite video as we all know) has something to do with the slightly less satisfactory audio? I am no expert, but seems plausible that it could be a factor...