flickering makes some games hard/impossible to play

[beta-tester]

Bug report

Describe the bug

Here is a clear and concise description of what the problem is:

on a Raspberry Pi (RPi3B) in combination with LibreELEC 9.1(v9.1-20191027) and Stella (atari2600 emulator),
there are some games where some objects are flickering extremely in a way (none-constant frequency), that it is hard or impossible to play.

• Astroids: the astroids are flickering.
• Pac-Man: the ghosts are flickering.
• Yar's Revenge: the safezone and the "shield" of the enemy are flickering.

under LibreELEC v9.1-20191027, the listed objects of the games are flickering in a none-constant frequency. it happens, that the flickering objects are not visible for longer time so that you don't see them and got hitten from an invisible object. it is hard or impossible survive/win the game.

RetroArch Behavior

Here is a clear and concise description of what happens in RetroArch with the same core/game:

i tried Lakka-RPi2.arm-2.3.1 (on the same SD card, on the same RPi3B, with the same Stella 2014 emulator and same games), there those objects are flickering as well, but in a way higher and more constant frequency so, that you mostely always are able to play/survive the game.

To Reproduce

Steps to reproduce the behavior:

1. download and update to LibreELEC-RPi2.arm-9.1-devel-20191027191757-4e65d03.tar
2. start LibreELEC on a RPi3B
3. install Atari2600 (Stella 2014) add-on
   (Add-Ons | Install from Repository | LibreELEC Add-ons | Game add-ons | Emulators | Atari - 2600 (Stella 2014) | Install | Ok)
4. navigate to Astroid.a26 / Pac-Man.a26 / Yars' Revenge.a26 rom and start the game

Debuglog

The debuglog can be found here:

Screenshots

Here are some links or screenshots to help explain the problem:

MP4 of issue.zip

• Astroids.mp4: see how the objects are not visible few times for around 1 second.
• Pac-Man.mp4: see how sometimes there are less than 4 ghosts visible for around 1 second (e.g. the ghost at bottom right corner)
• Yars' Revenge.mp4: see how the middle safezone and the rights "shield" disappear few times for a longer period.

Your Environment

Used Operating system:

• Android
• iOS
• Linux
• OSX
• Raspberri-Pi
• Windows
• Windows UWP

Operating system version/name:

Kodi version: 18.4 + patch LibreELEC-RPi2.arm-9.1-devel-20191027191757-4e65d03.tar, because with the normal unpatched version, the stella add-on is not usable.

note: Once the issue is made we require you to update it with new information or Kodi versions should that be required.
Team Kodi will consider your problem report however, we will not make any promises the problem will be solved.

[beta-tester]

because of the black screen issue #5, i just tried LibreELEC 9.2 with Kodi 18.5 and RetroPlayer patches (LibreELEC-RPi2.arm-9.2-devel-20191126203326-551ead9.tar), there the issue is also present.
subjectively it feels a tiny little bit even worse - the duration of periods, where all the objects are invisible seems to be a bit longer.

[atri11ion]

I realize beta-tester's post is from 2019 and it is now 2023, however I just started using New Retro Arcade: Neon this month. I purchased it from Steam for using with my Quest 2 in VR. I happen to love the game Yars' Revenge and I tried to use a version of stella2014_libretro.dll to run the game in the arcade and I got the exact same thing that beta-tester mentions. My safe zone and the enemies shield is flickering, and it's very distracting. I would like to know if there ever became a fix for this? I'm not a coder and I don't know how to compile code on github, so I was hoping you could point me to a download link for the already compiled dll for the core that might actually work in fixing this, if it's available of course. I appreciate your time and reading this.

[beta-tester]

that what is flickering in the emulator was flickering on the real hardware Atari 2600 as well. it was anoying ugly to watch, but that's how it was working back in the days.
(because of the low memory, slow CPU, CPU was driving the TV signal)

what i mean with my issue report is that on the emulator it is flickering in a way, that flickering parts starts to completely visually disapear for some time (i guess bacause of filckering frequence and emulator screen refresh rate interferes each others) and you loose a life because you couldn't see the enemy/hunter/obstacle/bullet/...

the stella emulator on other distros were working much better (flickering frequency and emulator screen refresh rate were kind of in sync) so it is flickering there but the flickering parts did not disapers for a longer time.

i tried LibreELEC 11 .0.3 RPi2.arm and Stella (Stella 2014) v 3.9.3 on my RPi3B+, and it is still a thing