Tips & Tweaks: Lx3, Lx4, Lx5 modes

[chmcarro]

I just performed the RGB mod on my NTSC N64 and connected to my 60″ 1080P HDTV via SNES Composite Sync SCART to the OSSC – I was able to output 480i in pass-through, 480P in 2x, 720P in 3x, 1280×1024 in 4x (is this right? I thought it would 4×240 not 4×256?), and 1080P cropped in 5x.

All options look more pixelated/dithered/blocky than what I was hoping to see. I attribute this to a couple things:

1. Personal exposure to better 3D graphics has altered my perception of how immersive the 3D graphics look on this system
2. The large 60″ screen is the biggest contributing factor to why the visuals are “poor” compared to smaller displays common to this era

I think I might have a more enjoyable experience if I was able to produce a 2x (480p) or 3x(720p) scanline image in a 1080P frame for pixel-perfect presentation (with very large black bars around the dot-for-dot image) effectively shrinking my screen. Is there a guide or output method so I may “shrink” my output for this effect?

Which RGB mod? The simple bypass, Tim Worthington’s, or one of Borti’s?

Retrofix’s N64 RGB Upgrade Kit (simple THS7316 amp on an early US N64). I should have gone with another board design. I did not integrate the N64’s Csync into the mod board as this board does not have a c-sync jumper or C-sync solder point. I’m using an unshielded Chinese SNES NTSC SCART cable. The OSSC is getting sync in RGBS format with component video sync. There’s no discernible difference in OSSC sync LPF options and from my eye test I don’t see any jailbars, sync stuttering, or discoloration so I feel fortunate in this regard. I’m not sure what improvement I would see from a sync on luma or shielded cable, but perhaps I am mistaken.

I believe a UltraHDMI, Tim Worthington’s or Borti’s de-blur option would NOT alleviate what I’ve described as a dithered/blocky image. From what I understand, that would actually be more blocky as it get’s a sharper image and removes some anti-aliasing.

Reducing my TV’s sharpness setting to 0 has assisted to some degree, but comparing to Youtube videos on a laptop screen my 60″ 1080P TV is producing a blockier image with more visible dithering.

The 1280×1024 TV mode when OSSC is outputting 4x does appear to be windowboxing.

I’m not sure I’m following you on the 4K suggestion because wouldn’t that still be a large full screen image?

[Mattyaceof]

Hi,

I have a Panasonic TX-P50X50B and L3X-L5X don’t work. I’m in the U.K so I use PAL and need some help please 🙂
I have the latest OSSC firmware and I want to use the 3x Generic 16:9 as my TV does not support game mode in it’s 4:3 mode and i’ve heard generic 16:9 will display 4:3 with black bars left and right on widescreen displays. Many Thanks

[Harrumph]

@Mattyaceof
If you have tried the various tweaks in the OP of this thread and it didn’t work, then I’m afraid your TV is simply not compatible. The tweaks are not as likely to work with PAL consoles, because the PC modes that are being aimed for expect 60Hz signal.

[Total Eclipse]

Much as I hate to revive old posts, I’ve recently been through the hassle of trying to get a PAL signal working in anything more than x2 (in this case, an Amiga, ST and a load of 8 bit machines, all courtesy of a MiST FPGA board (which should be outputting a largely identical signal to real hardware).

I’d picked up a 10 year old Samsung 55 inch TV recently, and it’s *really* picky about the signals that it receives.  However, I’ve also got a much more recent Sony TV that seems to take anything – It takes anything out of spec, like 1318×1080 and just displays it.  This meant I could adjust my OSSC settings and use the Sony TV to see exactly what was actually being output.

 

And after half an hour of messing around, I’ve got a x4 profile that gives a 1920×1080 50hz image on a screen that seemed to be completely incompatible at first glance.

 

The settings I’ve dialled in are as follows:

H. samplerate 2164.00
H. srate frac 2164.00
H. synclen 77
H. backporch 170
H. active 1920
V. synclen 3
V. backporch 31
V. active 270
H. border 91
V. border 0
Sampling phase 180 deg

 

This is using firmware 1.08.  Hopefully it might provide a useful starting point for anyone else trying to get a PAL 50hz image on a picky screen.

 

EDIT: I appreciate that some fairly similar figures were posted right at the beginning of this thread, however the settings I had to dial in are very precise.  Even setting the H. samplerate to say, 2166 instead of 2164 would have some odd consequences.  If I recall, the Samsung TV would then receive a 1922×1080 signal instead of 1920, and simply refuse to display it.

• This reply was modified 9 months ago by Total Eclipse.

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