Shader challenge: maximize dynamic range

[Nesguy]

The old challenge (maintain 2:1 scanlines while maintaining good contrast) was impossible so here’s a new one: beat the dynamic range that I’ve achieved with guest-dr-venom.

There should be no clipping and no crushed blacks. Settings should pass the sharpness test in 240p Test Suite. The sides of the black circle should appear solid black at normal viewing distance. Masks, if used, should be visible at normal viewing distance (2-3 times the width of the display, counting only the visible area and not the black bars)

Other factors to consider are scaling algorithms and sharpness/blur. Based on these considerations, I’ve completely ruled out a lot of shaders. Many are either too sharp or too blurry no matter what you do, have very limited mask options which are not suitable for 1080p or higher resolution displays, have strange-looking scaling algorithms which cause unwanted artifacts or lost detail, or simply can’t achieve the same dynamic range as guest-dr-venom with the options available.

Here are the shaders I have yet to rule out.

CRT-geom-deluxe

CRT-lottes

CRT-royale

MAME HLSL

Combining shaders is fine.

Here are my guest-dr-venom settings:

shaders = "10"
shader0 = "shaders_slang/stock.slang"
filter_linear0 = "false"
wrap_mode0 = "clamp_to_border"
mipmap_input0 = "false"
alias0 = ""
float_framebuffer0 = "false"
srgb_framebuffer0 = "false"
scale_type_x0 = "source"
scale_x0 = "1.000000"
scale_type_y0 = "source"
scale_y0 = "1.000000"
shader1 = "shaders_slang/stock.slang"
filter_linear1 = "true"
wrap_mode1 = "clamp_to_border"
mipmap_input1 = "false"
alias1 = ""
float_framebuffer1 = "false"
srgb_framebuffer1 = "false"
scale_type_x1 = "source"
scale_x1 = "1.000000"
scale_type_y1 = "source"
scale_y1 = "1.000000"
shader2 = "shaders_slang/misc/grade.slang"
filter_linear2 = "true"
wrap_mode2 = "clamp_to_border"
mipmap_input2 = "false"
alias2 = "WhitePointPass"
float_framebuffer2 = "false"
srgb_framebuffer2 = "false"
scale_type_x2 = "source"
scale_x2 = "1.000000"
scale_type_y2 = "source"
scale_y2 = "1.000000"
shader3 = "shaders_slang/crt/shaders/guest/afterglow.slang"
filter_linear3 = "true"
wrap_mode3 = "clamp_to_border"
mipmap_input3 = "false"
alias3 = "AfterglowPass"
float_framebuffer3 = "false"
srgb_framebuffer3 = "false"
scale_type_x3 = "source"
scale_x3 = "1.000000"
scale_type_y3 = "source"
scale_y3 = "1.000000"
shader4 = "shaders_slang/crt/shaders/guest/avg-lum.slang"
filter_linear4 = "true"
wrap_mode4 = "clamp_to_border"
mipmap_input4 = "true"
alias4 = "AvgLumPass"
float_framebuffer4 = "true"
srgb_framebuffer4 = "false"
scale_type_x4 = "source"
scale_x4 = "1.000000"
scale_type_y4 = "source"
scale_y4 = "1.000000"
shader5 = "shaders_slang/crt/shaders/guest/linearize.slang"
filter_linear5 = "true"
wrap_mode5 = "clamp_to_border"
mipmap_input5 = "false"
alias5 = "LinearizePass"
float_framebuffer5 = "true"
srgb_framebuffer5 = "false"
scale_type_x5 = "source"
scale_x5 = "1.000000"
scale_type_y5 = "source"
scale_y5 = "1.000000"
shader6 = "shaders_slang/crt/shaders/guest/blur_horiz.slang"
filter_linear6 = "true"
wrap_mode6 = "clamp_to_border"
mipmap_input6 = "false"
alias6 = ""
float_framebuffer6 = "true"
srgb_framebuffer6 = "false"
scale_type_x6 = "source"
scale_x6 = "1.000000"
scale_type_y6 = "source"
scale_y6 = "1.000000"
shader7 = "shaders_slang/crt/shaders/guest/blur_vert.slang"
filter_linear7 = "true"
wrap_mode7 = "clamp_to_border"
mipmap_input7 = "false"
alias7 = "GlowPass"
float_framebuffer7 = "true"
srgb_framebuffer7 = "false"
scale_type_x7 = "source"
scale_x7 = "1.000000"
scale_type_y7 = "source"
scale_y7 = "1.000000"
shader8 = "shaders_slang/crt/shaders/guest/linearize_scanlines.slang"
filter_linear8 = "true"
wrap_mode8 = "clamp_to_border"
mipmap_input8 = "false"
alias8 = ""
float_framebuffer8 = "true"
srgb_framebuffer8 = "false"
scale_type_x8 = "source"
scale_x8 = "1.000000"
scale_type_y8 = "source"
scale_y8 = "1.000000"
shader9 = "shaders_slang/crt/shaders/guest/crt-guest-dr-venom.slang"
filter_linear9 = "true"
wrap_mode9 = "clamp_to_border"
mipmap_input9 = "false"
alias9 = ""
float_framebuffer9 = "false"
srgb_framebuffer9 = "false"
scale_type_x9 = "viewport"
scale_x9 = "1.000000"
scale_type_y9 = "viewport"
scale_y9 = "1.000000"
parameters = "g_gamma_in;g_signal_type;g_gamma_type;g_crtgamut;g_space_out;g_hue_degrees;g_I_SHIFT;g_Q_SHIFT;g_I_MUL;g_Q_MUL;g_lum_fix;g_vignette;g_vstr;g_vpower;g_lum;g_cntrst;g_mid;wp_temperature;g_sat;g_satr;g_satg;g_satb;g_vibr;g_lift;blr;blg;blb;wlr;wlg;wlb;rg;rb;gr;gb;br;bg;LUT_Size1;LUT1_toggle;LUT_Size2;LUT2_toggle;SW;AR;PR;AG;PG;AB;PB;sat;lsmooth;GAMMA_INPUT;TAPSH;GLOW_FALLOFF_H;TAPSV;GLOW_FALLOFF_V;TATE;IOS;OS;BLOOM;brightboost;brightboost1;gsl;scanline1;scanline2;beam_min;beam_max;beam_size;h_sharp;s_sharp;csize;bsize;warpX;warpY;glow;shadowMask;masksize;vertmask;slotmask;slotwidth;double_slot;slotms;mcut;maskDark;maskLight;CGWG;gamma_out;spike;inter;interm;bloom;scans"
g_gamma_in = "2.500000"
g_signal_type = "1.000000"
g_gamma_type = "1.000000"
g_crtgamut = "2.000000"
g_space_out = "0.000000"
g_hue_degrees = "0.000000"
g_I_SHIFT = "0.000000"
g_Q_SHIFT = "0.000000"
g_I_MUL = "1.000000"
g_Q_MUL = "1.000000"
g_lum_fix = "0.000000"
g_vignette = "0.000000"
g_vstr = "40.000000"
g_vpower = "0.200000"
g_lum = "0.000000"
g_cntrst = "0.000000"
g_mid = "0.500000"
wp_temperature = "6505.000000"
g_sat = "0.000000"
g_satr = "0.000000"
g_satg = "0.000000"
g_satb = "0.000000"
g_vibr = "0.000000"
g_lift = "0.000000"
blr = "0.000000"
blg = "0.000000"
blb = "0.000000"
wlr = "1.000000"
wlg = "1.000000"
wlb = "1.000000"
rg = "0.000000"
rb = "0.000000"
gr = "0.000000"
gb = "0.000000"
br = "0.000000"
bg = "-0.005000"
LUT_Size1 = "16.000000"
LUT1_toggle = "0.000000"
LUT_Size2 = "64.000000"
LUT2_toggle = "0.000000"
SW = "1.000000"
AR = "0.070000"
PR = "0.050000"
AG = "0.070000"
PG = "0.050000"
AB = "0.070000"
PB = "0.050000"
sat = "0.100000"
lsmooth = "0.900000"
GAMMA_INPUT = "2.400000"
TAPSH = "4.000000"
GLOW_FALLOFF_H = "0.000000"
TAPSV = "4.000000"
GLOW_FALLOFF_V = "0.000000"
TATE = "0.000000"
IOS = "0.000000"
OS = "1.000000"
BLOOM = "0.000000"
brightboost = "0.500000"
brightboost1 = "1.500000"
gsl = "2.000000"
scanline1 = "15.000000"
scanline2 = "5.000000"
beam_min = "1.000000"
beam_max = "1.000000"
beam_size = "0.000000"
h_sharp = "3.000000"
s_sharp = "1.000000"
csize = "0.000000"
bsize = "600.000000"
warpX = "0.000000"
warpY = "0.000000"
glow = "0.000000"
shadowMask = "-1.000000"
masksize = "1.000000"
vertmask = "0.000000"
slotmask = "0.000000"
slotwidth = "2.000000"
double_slot = "1.000000"
slotms = "1.000000"
mcut = "0.250000"
maskDark = "0.500000"
maskLight = "1.500000"
CGWG = "0.300000"
gamma_out = "2.400000"
spike = "1.000000"
inter = "400.000000"
interm = "1.000000"
bloom = "0.000000"
scans = "1.000000"
textures = "SamplerLUT1;SamplerLUT2;SamplerLUT3"
SamplerLUT1 = "shaders_slang/crt/shaders/guest/lut/sony_trinitron1.png"
SamplerLUT1_linear = "true"
SamplerLUT1_wrap_mode = "clamp_to_border"
SamplerLUT1_mipmap = "false"
SamplerLUT2 = "shaders_slang/crt/shaders/guest/lut/sony_trinitron2.png"
SamplerLUT2_linear = "true"
SamplerLUT2_wrap_mode = "clamp_to_border"
SamplerLUT2_mipmap = "false"
SamplerLUT3 = "shaders_slang/crt/shaders/guest/lut/other1.png"
SamplerLUT3_linear = "true"
SamplerLUT3_wrap_mode = "clamp_to_border"
SamplerLUT3_mipmap = "false"

[c9f5fdda06]

We might need someone who could add HDR to Retroarch. On an OLED you can have a 700 nit white pixel next to 0 nit black pixel with HDR. Not 100% sure if this is the fix but might be worth considering. I recall hunterk said we currently don’t have someone who could add this to the program.

[Nesguy]

Yeah, that would probably do it!

Brightness isn’t as important as contrast ratio. 50 nits would be fine in a totally dark room. We really just need much better contrast ratios to do mask stuff without degrading the image. Scanlines are much more important. I’d rather have good scanlines and no mask than crappy scanlines and a crappy mask.

[Nesguy]

@Dogway

Want to take a stab at this?

[Dogway]

Had crazy issues calibrating with madVR, 5 hours in a row because the damned program failed at the end every time lol. When I get more time I will check this out, probably from Wednesday next week.

[Nesguy]

I don’t think it can actually be done, tbh. This is one of those things where I’d be happy to be proven wrong.

2:1 scanlines causes such a reduction in brightness/contrast that there isn’t enough left over for the mask.

Instead, when using a mask effect we should just maximize the dynamic range of the scanlines, which gives us maximum headroom for the mask.

[Nesguy]

New challenge:

Achieve greater dynamic range than what I’ve achieved in guest-dr-venom while also maintaining good sharpness and mask visibility at normal viewing distance. See first post for more info.