Magnavox - Odyssey2 / Philips Videopac+ (O2EM)¶

Background¶

O2EM is an open source multi-platform Odyssey2 / Videopac+ emulator. The Odyssey2 (Videopac/Jopac in Europe) was a video game console created in the late 70s.

The O2EM core has been authored by

Daniel Boris
Andre de la Rocha
Arlindo M. de Oliveira

The O2EM core is licensed under

Artistic License

A summary of the licenses behind RetroArch and its cores can be found here.

BIOS¶

Required or optional firmware files go in the frontend's system directory.

Filename	Description	md5sum
o2rom.bin	Odyssey2 BIOS - G7000 model - Required	562d5ebf9e030a40d6fabfc2f33139fd
c52.bin	Videopac+ French BIOS - G7000 model - Required	f1071cdb0b6b10dde94d3bc8a6146387
g7400.bin	Videopac+ European BIOS - G7400 model - Required	c500ff71236068e0dc0d0603d265ae76
jopac.bin	Videopac+ French BIOS - G7400 model - Required	279008e4a0db2dc5f1c048853b033828

Currently the libretro core only works with the o2rom.bin. As a workaround for playing Videopac+ games, you can rename the g7400.bin firmware file into o2rom.bin, and the core plays it correctly as a Videopac+ game.

Extensions¶

Content that can be loaded by the O2EM core have the following file extensions:

.bin

RetroArch database(s) that are associated with the O2EM core:

Features¶

Frontend-level settings or features that the O2EM core respects.

Feature	Supported
Restart	✔
Saves	✕
States	✔
Rewind	✔
Netplay	✕
Core Options	✔
RetroAchievements	✔
RetroArch Cheats	✕
Native Cheats	✕
Controls	✔
Remapping	✔
Multi-Mouse	✕
Rumble	✕
Sensors	✕
Camera	✕
Location	✕
Subsystem	✕
Softpatching	✕
Disk Control	✕
Username	✕
Language	✕
Crop Overscan	✕
LEDs	✕

Directories¶

The O2EM core's library name is 'O2EM'

The O2EM core saves/loads to/from these directories.

Frontend's State directory

File	Description
*.state#	State

Geometry and timing¶

The O2EM core's core provided FPS is 60 for NTSC games and 50 for PAL games
The O2EM core's core provided sample rate is 44100 Hz
The O2EM core's base width is 340
The O2EM core's base height is 250
The O2EM core's max width is 340
The O2EM core's max height is 250
The O2EM core's core provided aspect ratio is 4/3

Core options¶

The O2EM core has the following option(s) that can be tweaked from the core options menu. The default setting is bolded.

Emulated Hardware (Restart) [o2em_bios] (o2rom.bin|Videopac G7000 (European)|Videopac+ G7400 (European)|Videopac+ G7400 (French))

Specify which console hardware to emulate. Requires the corresponding bios file to be present in the frontend 'system' directory (o2rom.bin, c52.bin, g7400.bin, jopac.bin)
Console Region (Restart) [o2em_region] (Auto|NTSC|PAL)

Specify which region the system is from. 'Auto' chooses the correct region based on emulated hardware. 'NTSC' is 60hz, 'PAL' is 50hz. Games may run abnormally if the wrong region is selected, and the setting my be overridden if the current content is incompatible.
Swap Gamepads [o2em_swap_gamepads] (disabled|enabled)

Swap inputs from the two connected controllers of the emulated console. Required for games such as UFO and P.T. Barnum's Acrobats, which accept player 1 input from the second controller.
Virtual keyboard transparency [o2em_vkb_transparency] (0%|25%|50%|75%)

Set transparency level of the virtual on-screen keyboard.

Virtual keyboard transparency - 0%

Virtual keyboard transparency - 25%

Virtual keyboard transparency - 50%

Virtual keyboard transparency - 75%

Crop Overscan [o2em_crop_overscan] (disabled|enabled)

Remove the border around the edges of the screen, typically unused by games and hidden by the bezel of a standard-definition television.
Interframe Blending [o2em_mix_frames] (Simple|Ghosting (65%)|Ghosting (75%)|Ghosting (85%)|Ghosting (95%))

Simulate CRT phosphor ghosting effects. 'Simple' performs a 50:50 mix of the current and previous frames. 'Ghosting' accumulates pixels from multiple successive frames. May be used to alleviate screen flicker.
Audio Volume [o2em_audio_volume] (50%|0%)|5%)|10%)|15%|20%|25%|30%|35%|40%|45%|50%|55%|60%|65%|70%|75%|80%|85%|90%|95%|100%)

Set output audio volume level.
Voice Volume [o2em_voice_volume] (70%|0%)|5%)|10%)|15%|20%|25%|30%|35%|40%|45%|50%|55%|60%|65%|70%|75%|80%|85%|90%|95%|100%)

Set output volume level of 'The Voice' speech samples. The voice sampleset WAV files must be placed in the frontend 'system/voice' directory.
Audio Filter [o2em_low_pass_filter] (disabled|enabled)

Apply a low pass audio filter to soften the 'harsh' sound effects produced by most Odyssey2/Videopac+ games.
Audio Filter Level [o2em_low_pass_range] (60%|0%)|5%)|10%)|15%|20%|25%|30%|35%|40%|45%|50%|55%|60%|65%|70%|75%|80%|85%|90%|95%|100%)

Specify the cut-off frequency of the low pass audio filter. A higher value increases the perceived 'strength' of the filter, since a wider range of the high frequency spectrum is attenuated.

Joypad¶

RetroPad Inputs	User 1 input descriptors
	Up
	Down
	Left
	Right
	Action / Press Key (Virtual Keyboard)
	Move Virtual Keyboard Up/Down
	Show/Hide Virtual Keyboard

RetroPad Inputs	User 2 input descriptors
	Up
	Down
	Left
	Right
	Action

In some games, for example UFO/Satellite Attack, the original had the joypads swapped so that Player 1 was on Joypad 2. If you only use one Joypad, a workaround is to provide identical assignments of both Retropads to one joystick and save it as Game Remap or Core Remap.

Keyboard¶

RetroKeyboard Inputs	O2EM Inputs
Keyboard Return	Enter
Keyboard Space	Space
Keyboard Minus -	-
Keyboard Period .	.
Keyboard Slash /	/
Keyboard 0	0
Keyboard 1	1
Keyboard 2	2
Keyboard 3	3
Keyboard 4	4
Keyboard 5	5
Keyboard 6	6
Keyboard 7	7
Keyboard 8	8
Keyboard 9	9
Keyboard Equals =	=
Keyboard Question ?	?
Keyboard a	a
Keyboard b	b
Keyboard c	c
Keyboard d	d
Keyboard e	e
Keyboard f	f
Keyboard g	g
Keyboard h	h
Keyboard i	i
Keyboard j	j
Keyboard k	k
Keyboard l	l
Keyboard m	m
Keyboard n	n
Keyboard o	o
Keyboard p	p
Keyboard q	q
Keyboard r	r
Keyboard s	s
Keyboard t	t
Keyboard u	u
Keyboard v	v
Keyboard w	w
Keyboard x	x
Keyboard y	y
Keyboard z	z
Keyboard End	Clear

External Links¶

Last update: 2024-04-07