OSSC 480i tuning with 240p-test-suite/emulation

[Blair]

Hi everybody, I could not find much useful info on optimizing the 480i output of the OSSC. I'm assuming it's down to a lack of easy to find/use 480i test patterns for adjusting the sampling phase (in order to achieve optimal timings).

The 240p-test-suite is the community's gold standard for test patterns and signal generation on retro gaming hardware. So that's what I wanted to use... as most of you know it's not available (natively) for the Sony Ps2 (a system with a hefty amount of 480i only software). and I have no way of running Ps1 Iso's yet to try that 240p test version (I hope to set up FreePSXboot, UNIROM, or Tonyhax in the future and give that a go).

so I had the idea to use emulation for running the 240p-test-suite on a Ps2 system. and the results have been good (at least I think so). I've been meaning to post my ideas/findings here for some time. the emulator I used was PicoDrive in .elf format (an older port of a sega megadrive/genesis emulator ported from the psp to the ps2, can be found on most ps2 utility sites) retroarch and its more "up to date" emulation cores are also available on ps2 and might work better, (but I haven't had the time to read a guide for setting up the ps2 version of retroarch). once users start replacing the original OSSC with retro tink5x or the New OSSC Pro this info will be deprecated as those devices will do most of this automatically.

Probably a better way to do this, but this is what I had on hand for testing. (so any suggestions or feedback would be greatly appreciated).

click the spoiler tags to display images of the process below

If you run the emulator from a usb drive with uLaunchElf it will look like this.

Spoiler

If you run the emulator from a memory card it will look like this (skins don't load from the memory card I guess).

Spoiler

I load the 240p test .rom file from whatever folder its located inside (usb, hdd, or mem card).

Spoiler

Sega 240p test main menu

Spoiler

not sure if setting the 240p tests internal 480i mode matters for this use case (since the emulator overrides all video output, but I always set it to "on" when in 480i mode.

Spoiler

the emulator has different video modes that I could also be used for adjusting the sampling phase and optimal timings of 480p, or 240p but this post is more geared to 480i as that seems to have the least amount of info available.

Spoiler

the main video modes for the emulator are NTSC NI (240p), 480p, and NTSC (480i).

Spoiler

the emulator has several different color "render modes" 8bit fast renderer seems to work best with this .elf version. change modes on the fly with the /\ triangle button

Spoiler

checkerboard test is the main test pattern we need to adjust *sampling phase* for the optimal settings (see OSSC Wiki or FBX and RetroRGB's videos on OSSC Optimal Timings for more info).

Spoiler

(http://junkerhq.net/xrgb/index.php?titl ... al_timings)
(https://www.youtube.com/watch?v=EBStHr4XCTg)
(https://www.youtube.com/watch?v=vHqT1God9vk)


the test pattern comes in two separate resolutions, from what I understand this is useful as different games on the same system output in slightly different resolutions. for instance Dead or Alive 2 H*C runs at 640x448 resolution, while Virtua Fighter 4 runs at 512x228 resolution. Both games will need separate profiles for optimal settings. we should pick the resolution mode closest to our game's target (internal rendering) resolution. so for Dead or Alive 2 H*C (640x448) we need to pick 320x224.

(finding the resolution for the game you want to optimize is very easy, just use PCSX2 the PlayStation 2 emulator, it's a super useful tool. just load your original game disc or .iso file and it will tell you the game resolution at the top of the window).

Spoiler

once the checkerboard pattern is on screen the final settings can be adjusted.

one last note, the 480i output mode of the OSSC has to be decided as the final optimal timings will be different based on the output method and the scenario you are trying to achieve. for instance if I am using optimal timings on a display or device that can do proper deinterlacing (like the XRGB-mini FRAMEMEISTER or directly into my HDTV) I'll use 480i Passthru, but if I am using a display or device that can't do proper deinterlacing (like my asus and dell lcd monitors, or a pc crt monitor) I'll use 480i Line2x, or Line4x. for some exotic solutions (like the extron DSC 301 HD) I'll use Line3x.

Spoiler

this article by techmind has a good visual representation of adjusting phase http://www.techmind.org/lcd/phasexplan.html



Here are the settings I arrived at with my two test games.
(and the help of the OSSC wiki: http://junkerhq.net/xrgb/index.php?titl ... al_timings)



your settings will likely look a bit different once they are all finalized for your personal setup.
(a Note about "Allow upsample2x", check the wiki for a description of this setting. I use it on a case-by-case basis).

OSSC Firmware v0.88

Game ID - SLPS-25026 (Dead or Alive 2 Hard*Core final ver. Japan)
Game internal resolution via pcsx2 - 640x448 (interlaced)

-Video in proc-
Video LPF - Auto

-Sampling opt-
Allow TVP HPLL2X - off
Allow upsample2x - off

<Advanced timing > (480i)
[H. Sample rate - 858.00]
[H. S.rate frac - 0.05]
[H. Synclen - 42]
[H. Backporch - 116]
[H. Active - 640]
[V. Synclen - 3]
[V. Backporch - 12]
[V. Active - 448]
[Sampling phase - 258]

-sync option-
Analog sync LPF - off
Analog STC LPF - 0.5Mhz (SDTV)

-output option-
HDMI ITC - on
TX mode - HDMI (RGB)
480i / 576i proc - Passthru

-compatibility-
Full TX setup - on

(placeholder image, video and screens to be posted later)

OSSC Firmware v0.88

Game ID - SLPM-62130 (Virtua Fighter 4 Japan)
Game internal resolution via pcsx2 - 512x228 (interlaced)


(this set up for External processor – Exotron HD 301)

-Video in proc-
Video LPF - Auto

-Sampling opt-
Allow TVP HPLL2X - off
Allow upsample2x - off

<Advanced timing > (480i)
[H. Sample rate - 615.00]
[H. S.rate frac - 0.10]
[H. Synclen - 42]
[H. Backporch - 25]
[H. Active - 512]
[V. Synclen - 3]
[V. Backporch - 23]
[V. Active - 224]
[Sampling phase - 180]

-sync option-
Analog sync LPF - off
Analog STC LPF - 4.8Mhz (HDTV)

-output option-
HDMI ITC - on
TX mode - HDMI (RGB)
480i / 576i proc - line3x (Laced)

-compatibility-
Full TX setup - on

(placeholder image, video and screens to be posted later)

[Kez]

Interesting stuff! Thanks for the writeup!