Alexander Gromnitsky's Blog

Batocera 35 and Vontar X3

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In the dining room there is an old (2013) 1080p telly with an old (2020) Android TV box connected to it. The TV box contains an ancient Amlogic S905X3 SoC inside. It has just enough power to play Youtube & 1080p movies from a network drive but not much else.

Some time ago I heard about repurposing this particular model (Vontar X3) as a retro-gaming console, but anticipating battles similar to those with openwrt-on-outers--where 2 devices with the exact same name have slightly different hardware revisions (& as a result, nothing works as expected)--I've been putting off the adventure.

The easiest Linux gaming distro to deploy is a French one called Batocera.1 Its wiki describes perfomance of a particular device in terms of console generation support:

Gén Consoles
3 NES
4 SNES, Sega Mega Drive
5 PlayStation (psx), PlayStation Portable (psp)

(I've skipped the irrelevant generations.)

In my tests, while the modest S905X3 runs most psx & psp games acceptably, some titles have such a perceived frame drop (that do not occur on a desktop PC running the same emulator as Batocera) that it makes them unplayable. The prominent unsuccessful examples are CTR: Crash Team Racing (psx) and MotorStorm: Arctic Edge (psp).

The last Batocera version for the Vontar X3 is 35 (the OS images for this device haven't been updated since '22). I dd'ed batocera-s905gen3-tvbox-gen3-35-20220910.img onto a 32GB SD card, inserted the card into the TV box, pressed its reset button with a toothpick, plugged in the power cable, & saw this:

The TV's info popups indicated that the resolution of this shaky image was 1080i (interlaced?) instead of the expected 1080p. I then tried 2 completely different (albeit much newer) TVs, as well as a capture card--none of them had any problems negotiating a proper resolution with Batocera.

After pointlessly suffering with various kernel parameters, I ended up with the following kludge to disable the interlaced mode:

  1. Connect the device to your LAN via the ethernet port. Batocera runs Avahi, hence we can just say

     $ ssh root@batocera.local
    

    (The password is 'linux'.)

  2. Run

     # batocera-resolution listModes | head -10
     max-1920x1080:maximum 1920x1080
     max-640x480:maximum 640x480
     0.0.1920x1080.60:HDMIA 1920x1080 60Hz (1920x1080i)
     0.1.1920x1080.60:HDMIA 1920x1080 60Hz (1920x1080)
     0.2.1920x1080.60:HDMIA 1920x1080 60Hz (1920x1080)
     0.3.1920x1080.60:HDMIA 1920x1080 60Hz (1920x1080i)
     0.4.1920x1080.50:HDMIA 1920x1080 50Hz (1920x1080)
     0.5.1920x1080.50:HDMIA 1920x1080 50Hz (1920x1080i)
     0.6.1920x1080.24:HDMIA 1920x1080 24Hz (1920x1080)
     0.7.1920x1080.24:HDMIA 1920x1080 24Hz (1920x1080)
    

    inside Batocera. Take a note of a mode you'd like to see.

  3. Turn the device off. Extract the SD card out of it & insert it into a PC. The card has 2 partition: the 1st one is fat32 that has batocera-boot.conf file. Add a line to it:

     es.resolution=0.1.1920x1080.60
    

The picture will still incessantly jerk from left to right, but only during the boot phase:

# batocera-info
Disk format: ext4
Temperature: 66°C
Architecture: tvbox-gen3
Model: Shenzhen Haochuangyi Technology Co., Ltd H96 Max
System: Linux 5.10.134
Available memory: 624/932 MB
Cpu model: ARMv8 Processor rev 0 (v8l)
Cpu number: 4
Cpu max frequency: 1908 MHz

There is little to add here. You copy your .nes/.sfc/.chd/.iso files to /userdata/roms/{nes,snes,psx,psp} either directly onto the 2nd partition of the SD card, or via ssh, or even smb, for Batocera runs Samba.


  1. I couldn't find any guidance on how to pronouce it: there is a type of beetles called /bə'tosərə/, but some youtubers say it as /bαto'sɛrα/.

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Authors: ag