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O2EM - RetroBIOS
Type libretro
Classification community_fork
Source https://github.com/libretro/libretro-o2em
Upstream https://sourceforge.net/projects/o2em/
Version 1.18
Profiled 2026-03-24
Cores o2em_libretro
Systems odyssey2, videopac
Core ID o2em_libretro
Technical notes

Libretro port of O2EM, an Odyssey2/Videopac emulator by Daniel Boris and André de la Rocha. Port by Arlindo M. de Oliveira.

One BIOS ROM selected via o2em_bios core option (default o2rom.bin). Loaded into rom_table[0] (1024 bytes), identified by CRC32. vpp=1 for Videopac+ variants (g7400.bin, jopac.bin). Core fails to load without the selected BIOS.

Voice module ("The Voice" speech synthesis add-on) emulation via WAV samples in system/voice/. 9 banks × 128 samples, named {bank}{sample}.WAV (e.g. E480.WAV). Compiled with HAVE_VOICE=1 on most platforms. Optional: core works without samples, speech is silently skipped.

BIOS loading: libretro.c load_bios() lines 145-212. BIOS selection: libretro_core_options.h lines 52-64. Voice loading: voice.c init_voice() lines 38-79, called from libretro.c:1025-1032.

5 files | 4 required, 1 optional | 4 in repo, 1 missing Categories: 4 BIOS, 1 game data

o2rom.bin -required, north-america

c52.bin -required, europe

  • System: videopac
  • Size: 1.0 KB
  • SHA1: a6120aed50831c9c0d95dbdf707820f601d9452e
  • MD5: f1071cdb0b6b10dde94d3bc8a6146387
  • CRC32: a318e8d6
  • Validation: size, crc32
  • Source: libretro.c:192-197
  • Platforms: batocera, lakka, recalbox, retroarch, retrobat, retrodeck, retropie
  • Videopac G7000 European BIOS. vpp=0, auto-sets PAL.

g7400.bin -required, europe

  • System: videopac
  • Size: 1.0 KB
  • SHA1: 5130243429b40b01a14e1304d0394b8459a6fbae
  • MD5: c500ff71236068e0dc0d0603d265ae76
  • CRC32: e20a9f41
  • Validation: size, crc32
  • Source: libretro.c:187-191
  • Platforms: batocera, lakka, recalbox, retroarch, retrobat, retrodeck, retropie
  • Videopac+ G7400 European BIOS. vpp=1.

jopac.bin -required, france

  • System: videopac
  • Size: 1.0 KB
  • SHA1: 54b8d2c1317628de51a85fc1c424423a986775e4
  • MD5: 279008e4a0db2dc5f1c048853b033828
  • CRC32: 11647ca5
  • Validation: size, crc32
  • Source: libretro.c:198-203
  • Platforms: batocera, lakka, recalbox, retroarch, retrobat, retrodeck, retropie
  • Videopac+ G7400 French BIOS (JoPac). vpp=1.

voice/ -optional, game_data, missing from repo

  • Source: voice.c:38-79, libretro.c:1025-1032
  • The Voice speech synthesis WAV samples. 9 banks (E4, E8-EF) × 128 samples.

Generated on 2026-03-25T14:56:43Z