Mednafen PCE FAST

Libretro Cores
#1

I’m getting some weird behaviour with this (new user) and would like to know your opinion. I’m using a 15kHz CRT and get some tearing with vertical scrolling which isn’t there with other cores and the same options. This is my override file:

video_fullscreen_x = "256"
video_fullscreen_y = "224"
video_refresh_rate = "59.95"
video_vsync = "true"
video_hard_sync = "false"
video_hard_sync_frames = "0"
video_frame_delay = "0"

video_force_aspect = "true"
video_scale_integer = "true"
video_aspect_ratio = "1.142857143"
video_aspect_ratio_auto = "false"
aspect_ratio_index = 19

custom_viewport_width = "256"
custom_viewport_heighth = "224"
custom_viewport_x = 0
custom_viewport_y = 0
video_crop_overscan = "false"
video_black_frame_insertion = "false"
video_shared_context = "false"

I’ve tried everything there, really. From superwide resolutions and different vertical resolutions to any kind of combination with the aspect ratio options and cropping overscan. Also, I can’t this core to acknowledge the refresh rate I type there, unlike other cores. It’s always 60.1 no matter what. It’s not that different to the supposedly original refresh (~59.82 according to MAME), but I thought RA allowed for these changes. Is it core-dependent, so that Mednafen PCE FAST originally is coded for 61.1 and RA couldn’t touch that?

#2

For the vertical scrolling thing, try messing with the ‘last scanline’ option. On my arcade monitor, it needs to be 223…? (or maybe it’s 225? I can’t remember, just that it wasn’t 224 as I expected).

RetroArch will typically just lock to whatever refresh rate the display is using. If it’s a slightly lower res than the others, it could be using a slightly higher refresh, dunno.

#3

Hi. Thanks for the answer. I’m afraid nor 223, nor 225, nor 239, nor 242 work to solve the “tearing effect”. It indeed looks as if there’s some kind of vertical scaling involved, more than the usual tearing effect.

How does RA use CD-ROM images, by the way? Is it required to mount them or any format can be loaded?

#4

Nevermind. Found it: http://emulation.gametechwiki.com/index.php/Cue_sheet_(.cue)

You can’t load a physical CD-ROM with any Mednafen core, can you?

#5

Not through RetroArch, no.

Do you have integer scaling enabled?

#6

Just use the “sharpen-lighter-box” shader and you will have the guarantee that the picture will be pixel perfect.

#7

1:1 resolution CRT user here. A shader should not be the way, but thanks.

[QUOTE=hunterk;45077] Do you have integer scaling enabled?[/QUOTE]

Yeah, I tried enabled and disabled, and with/without video_force_aspect. If you have your related options on hand and are sure you don’t get pixel distortion in vertical scrolling, maybe you can paste them here?

#8

I don’t have my config handy but it’s crop overscan ON, last scanline 223 (I think), integer scale, fullscreen, video_aspect_ratio = “-1.0000”, aspect_ratio_index = “22”, video_aspect_ratio_auto = “false”

#9

I’m also a 1:1 resolution CRT user. And that shader works perfectly for this purpose. You just need to disable the sharpen factor, setting the value to zero. And change the aspect ratio if the picture is cropped.

#10

Ah, thanks. Will look into it.

I think that may be my problem. I didn’t understand you’re talking about an actual option (and not the full_resolution values) since I didn’t find it explained anywhere. What’s the correct syntax for that, please?

#11

It’s in the core options. Load up a game, go back into the quick menu, go down to options and you should see first/last scanline options. Change it from 224 to 223.

#12

Got it, thanks. It works for me with initial scanline 1 and last 240, but I’m using a 256x240 mode under the core provided aspect ratio currently. Couldn’t get it to work with a super wide resolution, but I don’t think I fully understand all the aspect ratio-related options (there’s even another one in the core options!). (Hopefully the non-FAST version of Mednafen PCE is added soon, BTW)

Anyway, a couple of final questions for now, if may I - are these:

video_hard_sync = “true” video_hard_sync_frames = “3” video_frame_delay = “15”

the theoretical optimal settings for the lag thing, assuming your PC has enough power? Or is frame_delay redundant there?

Has D3D all the benefits of OpenGL regarding RA’s syncronization engine?

#13

You want the hard sync frames as low as possible. 0 is best. Frame delay should go as high as possible without crackling (varies per-core and sometimes even per-game). I don’t have a lot of experience with the d3d driver but I assume most of those options still act the same with it.

#14

video_frame_delay is really annoying as it varies depending on anything you run: not just a particular core but also a particular game. You’d rather put it back to 0 while still fixing your issues.

hardsync frame to 0 can be expensive, it’s OK with PCE if your cpu isn’t too bad. It needs to be put on 1 or disable with the most cpu intensive cores (some Mame games, Saturn…).

#15

Since this thread is labeled “Mednafen PCE FAST” I’m gonna hijack it with a question and skip the redundancy of creating a new thread with the exact same name.

How much less accurate is this core compared to the regular non-fast Mednafen PCE module?

I only have 1 game, Dracula X - Chi no Rondo for reference to begin with so I don’t know the PC-Engine emulation that well.

I have played the game in both Libretro and standalone and can’t say I have seen any difference in emulation.

What’s the biggest difference, what is is that the PCE Fast does different?

#16

There are two games I’ve had noticeable problems with in PCE Fast that work fine in Mednafen stand alone’s default PCE mode (accuracy). Violent Soldier has a glitchy line that appears sometimes and Popful Mail has glitchy cutscenes that can freeze.

Mednafen’s documentation explains what PCE Fast is: “The “pce_fast” emulation module is an experimental alternative to the pce emulation module. It is a fork of 0.8.x modified for speed at the expense of (usually) unneeded accuracy(this compares to the “pce” module, which traded speed away in favor of accuracy).”

#17

[QUOTE=Awakened;45386]There are two games I’ve had noticeable problems with in PCE Fast that work fine in Mednafen stand alone’s default PCE mode (accuracy). Violent Soldier has a glitchy line that appears sometimes and Popful Mail has glitchy cutscenes that can freeze.

Mednafen’s documentation explains what PCE Fast is: “The “pce_fast” emulation module is an experimental alternative to the pce emulation module. It is a fork of 0.8.x modified for speed at the expense of (usually) unneeded accuracy(this compares to the “pce” module, which traded speed away in favor of accuracy).”[/QUOTE]

Interesting, thanks for taking your time to answer my question!

I like how they say that accuracy is unneeded. Accuracy is definitely not unneeded and the accuracy module should have been the only choice when they ported Mednafen PCE to Libretro from the beginning.

However, the fast core is the only one in Libretro so we’ll have to take it for what it is. At least it plays Dracula X - Chi no Rondo fine and looks good with shaders.

#18

If a tree falls in the forest and no one is around to hear it, does it make a sound?

#19

What do you mean?

#20

I think he means there’s some invisible lumberjack tribe in that forest. Some of them could be deaf perhaps.