Neo Geo CRT Issue - Flickering at top of screen

[StrafeMcgee]

Hey folks.

Looking for help with an issue I'm having with the neo geo core. I'm using the IO board to send RGB via SCART to the TV. This works fine for the other cores, but for the Neo Geo I'm seeing a weird flicker/distortion in the top 20 % of the screen. The rest of the image is being rendered fine.

Other cores, like SNES and Genesis, are rendering fine, so it isn't a universal issue, whatever it is.

My Mister INI settings are:

SETTINGS START:

[MiSTer]
key_menu_as_rgui=0 ; set to 1 to make the MENU key map to RGUI in Minimig (e.g. for Right Amiga)
forced_scandoubler=0 ; set to 1 to run scandoubler on VGA output always (depends on core).
ypbpr=0 ; set to 1 for YPbPr on VGA output.
composite_sync=1 ; set to 1 for composite sync on HSync signal of VGA output.
vga_scaler=0 ; set to 1 to connect VGA to scaler output.
hdmi_audio_96k=0 ; set to 1 for 96khz/16bit HDMI audio (48khz/16bit otherwise)
keyrah_mode=0x18d80002 ; VIDPID of keyrah for special code translation (0x23418037 for Arduino Micro)
vscale_mode=1 ; 0 - scale to fit the screen height.
; 1 - use integer scale only.
; 2 - use 0.5 steps of scale.
; 3 - use 0.25 steps of scale.
vscale_border=0 ; set vertical border for TVs cutting the upper/bottom parts of screen (1-399)
;bootscreen=0 ; uncomment to disable boot screen of some cores like Minimig.
;mouse_throttle=10 ; 1-100 mouse speed divider. Useful for very sensitive mice
rbf_hide_datecode=0 ; 1 - hides datecodes from rbf file names. Press F2 for quick temporary toggle
menu_pal=0 ; 1 - PAL mode for menu core
hdmi_limited=0 ; 1 - use limited (16..235) color range over HDMI
; 2 - use limited (16..255) color range over HDMI, for VGA converters.
direct_video=0 ; 1 - enable core video timing over HDMI, use only with VGA converters.
fb_size=0 ; 0 - automatic, 1 - full size, 2 - 1/2 of resolution, 4 - 1/4 of resolution.
fb_terminal=1 ; 1 - enabled (default), 0 - disabled
osd_timeout=30 ; 5-3600 timeout (in seconds) for OSD to disappear in Menu core. 30 seconds if not set.
; Background picture will get darker after double timeout
osd_rotate=0 ; Display OSD menu rotated, 0 - no rotation, 1 - rotate right (+90°), 2 - rotate left (-90°)

; 1 - enables the recent file loaded/mounted.
; WARNING: This option will enable write to SD card on every load/mount which may wear the SD card after many writes to the same place
; There is also higher chance to corrupt the File System if MiSTer will be reset or powered off while writing.
recents=0

; lastcore - Autoboot the last loaded core (corename autosaved in CONFIG/lastcore.dat) first found on the SD/USB
; lastexactcore - Autoboot the last loaded exact core (corename_yyyymmdd.rbf autosaved in CONFIG/lastcore.dat) first found on the SD/USB
; corename - Autoboot first corename_*.rbf found on the SD/USB
; corename_yyyymmdd.rbf - Autoboot first corename_yyyymmdd.rbf found on the SD/USB
;bootcore=lastcore ; uncomment to autoboot a core, as the last loaded core.

; 10-30 timeout before autoboot, comment for autoboot without timeout.
bootcore_timeout=10

; Option to load the custom font. Format is plain bitmap 8x8.
; Supported sizes of font:
; 768 bytes - chars 32-127 (only alpha + numeric)
; 1024 bytes - chars 0-127
; 1136 bytes - chars 0-141
; up to 2048 - only chars 0-141 will be used.
; if first 32 chars are empty (for sizes 1024 bytes and more) then they are skipped.
font=font/Default.pf

; USER button emulation by keybaord. Usually it's reset button.
; 0 - lctrl+lalt+ralt (lctrl+lgui+rgui on keyrah)
; 1 - lctrl+lgui+rgui
; 2 - lctrl+lalt+del
; 3 - same as 0 (lctrl+lalt+ralt on keyrah)
reset_combo=0

; set to 1 for DVI mode. Audio won't be transmitted through HDMI in DVI mode.
dvi_mode=1

; 0 - 1280x720@60
; 1 - 1024x768@60
; 2 - 720x480@60
; 3 - 720x576@50
; 4 - 1280x1024@60
; 5 - 800x600@60
; 6 - 640x480@60
; 7 - 1280x720@50
; 8 - 1920x1080@60
; 9 - 1920x1080@50
;10 - 1366x768@60
;11 - 1024x600@60
;12 - 1920x1440@60
;13 - 2048x1536@60
;
; custom mode: hact,hfp,hs,hbp,vact,vfp,vs,vbp,Fpix_in_KHz

video_mode=352,26,34,73,240,4,3,15,7383
;video_mode=12

; set to 1-10 (seconds) to display video info on startup/change
video_info=10

; Set to 1 for automatic HDMI VSync rate adjust to match original VSync.
; Set to 2 for low latency mode (single buffer).
; This option makes video butter smooth like on original emulated system.
; Adjusting is done by changing pixel clock. Not every display supports variable pixel clock.
; For proper adjusting and to reduce possible out of range pixel clock, use 60Hz HDMI video
; modes as a base even for 50Hz systems.
vsync_adjust=0

; If you monitor doesn't support either very low (NTSC monitors may not support PAL) or
; very high (PAL monitors may not support NTSC) then you can set refresh_min and/or refresh_max
; parameters, so vsync_adjust won't be applied for refreshes outside specified.
; These parameters are valid only when vsync_adjust is non-zero.
refresh_min=40
refresh_max=60

; These parameters have the same format as video_mode.
; You need to supply both PAL and NTSC modes if you want vsync_adjust to switch between
; predefined modes as a base. This will reduce the range of pixel clock.
video_mode_ntsc=9 ;1920,8,20,20,1440,2,4,3,170000 ; 1920×1440 @60hz
video_mode_pal=9 ;1920,8,20,20,1440,2,4,3,141667 ; 1920×1440 @50hz

; 1-10 (seconds) to display controller's button map upon first time key press
; 0 - disable
controller_info=10

; JammaSD/J-PAC/I-PAC keys to joysticks translation
; You have to provide correct VID and PID of your input device
; Examples: Legacy J-PAC with Mini-USB or USB capable I-PAC with PS/2 connectors VID=0xD209/PID=0x0301
; USB Capable J-PAC with only PS/2 connectors VID=0x04B4/PID=0x0101
; JammaSD: VID=0x04D8/PID=0xF3AD
jamma_vid=0x04D8
jamma_pid=0xF3AD

; Disable merging input devices. Use if only player 1 works.
; Leave no_merge_pid empty to apply this to all devices with the same VID.
;no_merge_vid=0x045E
;no_merge_pid=0x028E

; Same as above but can add multiple devices (one entry per VIDPID). Format is VIDPID in hex number
;no_merge_vidpid=0x12345678
;no_merge_vidpid=0x11112222

; Speeds in sniper/non-sniper modes of mouse emulation by joystick
; 0 - (default) - faster move in non-sniper mode, slower move in sniper mode.
; 1 - movement speeds are swapped.
sniper_mode=0

; Uncomment following option if you don't want to see a second line for long file names in listing.
;browse_expand=0

; 0 - disable MiSTer logo in Menu core
logo=1

; Custom shared folder for core supporting this feature (currently minimig and ao486 only)
; Can be relative to core's home dir or absolute path.
; Path must exist before core start to use it, or it will fail.
; Make sure USB device is mounted before use shared folder on USB!
shared_folder=

; Custom aspect ratio
;custom_aspect_ratio_1=16:10
;custom_aspect_ratio_2=1:1

; use specific (VID/PID) mouse X movement as a spinner and paddle. Use VID=0xFFFF/PID=0xFFFF to use all mice as spinners.
;spinner_vid=0x1BCF
;spinner_pid=0x0005

; spinner_throttle with base value 100 gives one spinner step per one tick. Higher value makes spinner slower.
; Lower than 100 makes spinner faster. Negative value gives opposite direction.
;spinner_throttle=-50

; 0 - X axis, 1 - Y axis.
;spinner_axis=1

; Default filters for video scaler and audio. Paths must be relative to scaler/audio filter folder without leading slash.
;vfilter_default=LCD Effects/LCD_Effect_07.txt
;afilter_default=LPF2000_3tap.txt

; Defines internal joypad mapping from virtual SNES mapping in main to core mapping
; Set to 0 for name mapping (jn) (e.g. A button in SNES core = A button on controller regardless of position on pad)
; Set to 1 for positional mapping (jp) (e.g. A button in SNES core = East button on controller regardless of button name)
gamepad_defaults=0

; Write out file name under the cursor in browser for external integration
; External application or script may parse the info and do some additional actions and/or send info to 3rd party server.
; Warning: it may slowdown the system or add lag while browsing the files in OSD depending on external app/script.
log_file_entry=0

; Automatically disconnect (and shutdown) Bluetooth input device if not use specified amount of time.
; Some controllers have no automatic shutdown built in and will keep connection till battery dry out.
; 0 - don't disconnect automatically, otherwise it's amount of minutes.
bt_auto_disconnect=0

; Reset Bluetooth dongle before pair dialog.
; Some dongles may have problem to pair if not explicitly reset.
; Some dongles (mostly CSR) have problem to pair with BLE if not reset in advance.
; Consequence of reset: some input devices get shutdown after reset.
bt_reset_before_pair=0

SETTINGS END.

Outside of using the scaler (which usually just messes the image up and stops it from looking as crisp and nice,) does anyone know what might be causing the issue or have any settings that could fix it?

I'll upload footage of the issue once my camera's got some battery back.

Thanks

[StrafeMcgee]

Just noticed this is happening even when the Core's menu is shown and no rom is loaded.

[StrafeMcgee]

Additionally, also seems to be happening on the GBA core. Perhaps related to the resolution that these cores output at?

[FoxbatStargazer]

More likely the refresh rate. Both are further from 60hz than your average home console core. GBA is 59.7 and MVS is 59.1. Running in AES mode should bring the clock up to 59.59 but that probably won't be enough given your GBA issues.

You could try using the scaler to control the video output. (vga_scaler=1 or direct_video=0). Maybe start with a 244p video mode, then try increasing the vertical resolution slowly. Worse comes to worse you can use vsync_adjust=0 and a set refresh like 59.94 through the pixel clock number.

[akeley]

You can try this custom 60hz core: viewtopic.php?f=23&t=1438

Or this modeline:

[NeoGeo]
direct_video=0
vga_scaler=1
vsync_adjust=2
video_mode=320,21,29,44,224,13,14,13,6400

[StrafeMcgee]

Thanks. I thought the refresh rate might have been causing bother, so tried the 60hz core the other night. No luck though unfortunately

The issue appears to be occurring even when on the core menus - it’s not exclusively an in game thing, which I thought was unusual.

I’ll try the modeline later this evening.

[StrafeMcgee]

Had a go with the modeline and the scaler and the issue was still occurring. In fact, I tried using the video settings as the general output for the scaler and the issue was still occurring, even on the mister home menu! So I guess there must be some sort of issue with my display and the resolution settings for the neo geo core...

More experimentation needed, I guess.