Has anyone used a real CRT for lakka?

Libretro Lakka
#1

I plan on getting a CRT soon and I’m curious to know if anyone uses lakka, or if it’s even possible to use lakka on an older TV. Obviously it won’t have HDMI ports, so I’d have to buy an HDMI to composite cable converter of some sort. I’m just wondering if lakka would still be able to detect your resolution and all if I were to do that and if so, would roms run in their native resolution instead of being scaled up? I’ve never done anything like this before, but I believe it would add to the whole authentic aspect of it.

As I am now, I run Lakka in 720p so there’s a fair amount of noticeable artifacts when attempting to use a CRT shader. I could run at 1080p, but attempting to run lakka at x5 integral scale means a good chunk of screen is cut off from the top and bottom (it’s a 720p tv originally), and setting the scale to x4 is far too small for my tastes.

#2

I have used a cheap 10$ box hdmi to av on my windows 10 pc and i’ve run retroarch. I had to set my desktop to a low res i think is was around 480p just for the box to work. One thing i did notice is that the box introduce input lag, not much but some.

original nes on tv(actual console)

image.png1920×1080 2.09 MB

and retroarch:

20170228_192718.jpg4249×2390 2.66 MB
20170228_192746.jpg4249×2390 2.12 MB

its cuts off and its not filled all in on the sides but if you set nes aspect ratio to 4:3 it fills in the sides, tops still cuts off. prob could adjust manually but lazy. and would be hard to adjust just to this tv when i never use it. retroarch nes 4:3

image.png1920×1080 1.85 MB

I know not the same a using lakka but it gives you an idea.

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#3

On a regular TV, the easiest options are to accept 480i and use the composite out on an RPi (or the svideo out on an old laptop or GPU). If this firmware upgrade for RPi’s composite encoder pans out, it would be a much better alternative:

The best current option, IMO, is to softmod a Wii and run RetroArch through that.

1 Like
#4

Hmm, do you have any shaders running? It looks similar, but Mario seems to be a bit blurry compared to the NES itself. It’s not too bad though, and it could just be the picture.

The thing about Lakka though, is that you can’t really change the resolution manually, like you could in Windows. There may be a way to modify resolutions within the config files, but I see no method of doing so in the gui aside from core resolutions.

Thanks for your input by the way, and the pictures. Would you say that the input lag on the converter is considerably worse than using a HD tv? I currently have Hard Sync on, and I still notice input lag. Some games are better than others though.

#6

I might have to look into getting a Wii. I owned one a few years back and I softmodded it to do emulation, but I remember many games weren’t very smooth. At least, not n64 anyway.

Is 480i really that terrible for emulation?

#7

Homebrew N64 emulation isn’t going to be smooth on Wii. Your best option there is Wii VC (either legit or injection).

The blurriness you mentioned from nonekiller001’s shots is probably caused by it converting the signal from 480p on the PC side to 480i on the TV side (just as a note: old standard def NTSC TVs only accept/display 480i; so-called 240p is a hack on the standard 480i signal, and hardware that works with NTSC TVs typically does bog-standard 480i exclusively and doesn’t know how to handle the non-interlaced 240-line signals we want to produce).

If you want it to look as sharp as the real thing, you need to feed it a legit 240 non-interlaced signal, which is (currently) pretty difficult to do outside of a hacked Wii/U.

That said, if you’re using a shitty old 13" TV, 480i is going to look totally fine! The whole 240p obsession is a fidelity issue and if you can stomach the slightly worse picture with 480i, it’s much, much easier to produce through off-the-shelf adapters.

1 Like
#8

It really depends on the games for input lag but i think it’s a bit more than lcd tv’s. Also i had no shaders on so it, so the blurriness was from the box and type of signal it out puts, like hunterk said.

and the pics are screen shot of pics on my desktop because the real pics were too big and i couldnt get them uploaded.

#9

UPDATE: looks like that experimental firmware for RPi works! So, it’s now a viable platform for 240p without using a chain of funky adapters. Just get a 3.5mm to RCA breakout cable and you’re off to the races.

4 Likes
#10

Where did you find it?

#11

It’s buried in the middle of that giant github issue. Here’s a direct link: https://drive.google.com/uc?id=0B-6zmEDJwxZEME9lSEFZRmQ5RGs&export=download

and here’s how to install it:

Basically you need to copy all of the files into your /boot/ folder. Probably the easiest way is to power off your Pi, take out the microSD card, and plug it into a card reader on your computer. Then copy all of the files from the zip over into the boot folder (remember to back up the old versions first). After that, open /boot/config.txt and add the line popcornmix mentions above: sdtv_progressive_scan=1 Save, close, eject, put it back into your Pi, and boot it up.

2 Likes
#12

I’m testing it right now and it’s great on Lakka. But do you also have multiple “tearing” lines on vertical scrolling items (like vertical scrolling text or sprites) in Picodrive?

EDIT: it seems related to this bug

But in 240p is now much more evident in Picodrive :_(((

#13

There is a great Hardware addon for a Raspberry PI called Pi2Scart from Arcadeforge.net (around 35€). It outputs RGB Video, and even supports 240p. I had previously connected my RPI3 with Lakka to a 32" CRT via Composite, and recently got myself such a Pi2Scart. Difference in image quality is huge! And it comes with absolutely no input lag.

I can only recommend this Hardware Addon. This is by far the best and easiest solution to connect a CRT to a RPI.

I’ve also posted some image comparisons on my homepage.

2 Likes
#14

In places that included SCART ports on TVs, this is true, but in USA, most TVs came with only composite and coaxial/RF jacks, with Svideo and YPbPr ports for higher quality in the late 90s. We never got to experience the glory of 240p RGB except in arcades :frowning:

#15

Is it compatible with all Raspberry Pis ? I have a 1 and a 2.

#16

Yes, it apparently works with all of them. EDIT: urp, thought you meant the 240p firmware, but you meant the SCART thing. nvm!

#17

On the product Page it’s only about the Pi3, but it should work on any (model B), as it uses GPIO connection. I can test on a Pi2 and provide results later on.

1 Like
#18

Thanks for sharing this.

Posted it on the RetroPie forums

Looks like you usern name is available so go ahead and register :wink:

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#19

Please pardon me for being pedantic, but I’d like to know if anyone else has the same issue with Picodrive core (I’m on Raspberry Pi 1, 240p composite).

Picture is affected by strange horizontal lines that are much more evident on sprites with vertical scrolling (but these lines are always present). Here there are a couple of videos from Bare Knuckle III on Picodrive.

VIDEO 1 Look at the text that rolls vertically, it is “cut off” by these horizontal lines that seem always in the same position: https://1drv.ms/v/s!AgxFrlHsc5x409hjO8kbvGjjCdKmfw

VIDEO 2 Please look at the mouth of Axel (main character of the game): https://1drv.ms/v/s!AgxFrlHsc5x409hiAfhH7kSQLhVBBQ

VIDEO 3 Now please take a look at his eye: https://1drv.ms/v/s!AgxFrlHsc5x409hhBvVUn3r8oFmdkA

This only occurs with Picodrive core, not with other cores like FCEUMM. Maybe someone could confirm whether it has the same issue?

Thank you very much!

#20

That’s because the image is being stretched vertically. Do you have “crop overscan” enabled or disabled? The image is okay with GenPlusGX?

#21

Surely this is not an issue related to video settings: I’ve checked yet all possible combinations (crop overscan, aspect ratio, integer scaling), and yes, picture is OK with GenPlusGX (but it is much slower than Picodrive on my good old Raspberry Pi 1).

Any suggestions on who (developer) I could point out this problem?

Thank you very much!