The XRGB-mini is an A/D-converter and image processor with 1080p HDMI/DVI output. It converts analog RGB (RGB21, SCART), S-Video, Composite and Component to digital. It also has 2 HDMI inputs for image processing or passthrough.
Image processing highlights are upscaling, de-interlacing, scanlines effect and many tweakable parameters. The introduced latency is relatively low; often lower than when a device is connected to the TV's own analog inputs.
Following those guides will give you a clean, blocky & unfiltered look. That may be desirable for capturing/sharing footage, but probably not for when you're just playing. The XRGB-Mini can be configured produce a competent scanline effect. Combined with the scaler's horizontal filtering, a look comparable to a CRT will give low-resolution games (~240p) a more aesthetic look.
When I tweak the scanlines & scaler parameters, I aim for a more "rounded" pixel appearance. Imo, it still doesn't come close to a real CRT or even some CRT shaders for RetroArch, mostly because the variations in beam width are not simulated. But for playing on real hardware connected to a LCD display, it's a solid choice and the result still looks very good.
- Gamma: 15
- Brightness: 25
- Special A/D level: Increase/decrease for no white/black clipping
- Sharpness: 0 (or 1, but try you display's sharpness setting first; probably looks better than XRGB-mini's)
- Make sure to change the HDMI output to 50 Hz or 60 Hz to match what the console is outputting.
- IMAGE_MODE: PICTURE
- Scanlines: Enabled
- Scanlines: Disabled
- IMAGE_MODE: NATURAL
Sixth generation consoles
IMAGE_MODE set NATURAL gives the best IQ and least flicker due to Motion/Adaptive de-interlacing. However, the low-pass filter of other modes will reduce the edge "jaggies". It can look rather nice for many 3D games of this generation (especially on PS2), despite sometimes blurring fine details. I guess it is comparable to post-processing anti-aliasing in that regard.
Good modes to try that have low-pass filter enabled: STANDARD (Motion/Adaptive de-interlacing), GAME1 (Linear/Bob-deinterlacing) and GAME2 (Linear/Bob-deinterlacing, colors enhanced).
Going for a softer look without scanlines also makes it viable to use scaling modes (SCREEN_SET) other than SMART_X1 and SMART_X2, because you don't have to worry about irregular pixel appearance. With STANDARD (preferred) and NORMAL2 you can change H_WIDTH, V_WIDTH, H_POS and V_POS to fill the entire screen.
Position Special A/D level: Increase/decrease for no white/black clipping