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SMPTE RP219-1 pattern signal

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This commit is contained in:
Dmitry Sergeev
2026-09-16 00:09:16 +03:00
parent 72939c3be7
commit c3bcee6223
5 changed files with 158 additions and 18 deletions
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cmd/mxl-pattern/main.go
+10 -4
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@@ -192,16 +192,22 @@ type pattern struct {
var patterns = map[string]pattern{
"bars": {
name: "bars",
description: "SMPTE 75% color bars",
kernelPath: "kernels/static/smpteBars.wgsl",
description: "75% color bars",
kernelPath: "kernels/static/colorBars.wgsl",
motion: false,
},
"bars-move": {
name: "bars-move",
description: "SMPTE 75% color bars with moving square",
kernelPath: "kernels/dynamic/smpteBars.wgsl",
description: "75% color bars with moving square",
kernelPath: "kernels/dynamic/colorBars.wgsl",
motion: true,
},
"smpte": {
name: "smpte",
description: "SMPTE RP-219 Color Bar Signal",
kernelPath: "kernels/static/smpteBars.wgsl",
motion: false,
},
"gray-bars": {
name: "gray-bars",
description: "13-step grayscale bars (Y 64..940)",
internal/generator/text.go
+2 -2
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@@ -45,8 +45,8 @@ func LoadFace(path string, size float64) (font.Face, error) {
return face, nil
}
// NewTextOverlay rasterizes text (white, anti-aliased) onto a black backing
// box, centered horizontally. Box width and x are multiples of 6 so the box
// NewTextOverlay rasterizes text (white, anti-aliased) onto a black backing box.
// Box width and x are multiples of 6 so the box
// covers whole v210 blocks and the per-frame copy is word-aligned.
func NewTextOverlay(text string, frameW, frameH, posX, posY int, face font.Face) (*TextOverlay, error) {
if text == "" {
kernels/dynamic/smpteBars.wgsl → kernels/dynamic/colorBars.wgsl
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kernels/static/colorBars.wgsl
+50
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@@ -0,0 +1,50 @@
// 75% SMPTE color bars, Rec.709, 10-bit Y'CbCr, packed as v210 (4:2:2).
// One work-item per 16-byte block = 6 pixels (6 Y + 3 Cb + 3 Cr).
struct Params {
width: u32,
height: u32,
frame: u32,
_pad0: u32,
};
@group(0) @binding(0) var<storage, read_write> out: array<u32>;
@group(0) @binding(1) var<uniform> params: Params;
fn bar_index(px: u32) -> u32 {
return min((px * 7u) / params.width, 6u);
}
@compute @workgroup_size(64)
fn main(@builtin(global_invocation_id) gid: vec3<u32>) {
let block = gid.x;
let total = (params.width * params.height) / 6u;
if (block >= total) {
return;
}
let x = (block * 6u) % params.width;
// Bar order: 75% white, yellow, cyan, green, magenta, red, blue
let y_tab = array<u32, 7>(721u, 674u, 581u, 534u, 251u, 204u, 111u);
let cb_tab = array<u32, 7>(512u, 176u, 589u, 253u, 771u, 435u, 848u);
let cr_tab = array<u32, 7>(512u, 543u, 176u, 207u, 817u, 848u, 481u);
var y: array<u32, 6>;
var cb: array<u32, 6>;
var cr: array<u32, 6>;
for (var i = 0u; i < 6u; i++) {
let b = bar_index(x + i);
y[i] = y_tab[b];
cb[i] = cb_tab[b];
cr[i] = cr_tab[b];
}
// v210 word layout, chroma co-sited with luma samples 0/2/4:
// w0 = Cb0|Y0<<10|Cr0<<20; w1 = Y1|Cb2<<10|Y2<<20;
// w2 = Cr2|Y3<<10|Cb4<<20; w3 = Y4|Cr4<<10|Y5<<20
out[block * 4u + 0u] = (cb[0] & 0x3FFu) | ((y[0] & 0x3FFu) << 10u) | ((cr[0] & 0x3FFu) << 20u);
out[block * 4u + 1u] = (y[1] & 0x3FFu) | ((cb[2] & 0x3FFu) << 10u) | ((y[2] & 0x3FFu) << 20u);
out[block * 4u + 2u] = (cr[2] & 0x3FFu) | ((y[3] & 0x3FFu) << 10u) | ((cb[4] & 0x3FFu) << 20u);
out[block * 4u + 3u] = (y[4] & 0x3FFu) | ((cr[4] & 0x3FFu) << 10u) | ((y[5] & 0x3FFu) << 20u);
}
kernels/static/smpteBars.wgsl
+93 -9
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@@ -1,5 +1,5 @@
// 75% SMPTE color bars, Rec.709, 10-bit Y'CbCr, packed as v210 (4:2:2).
// One work-item per 16-byte block = 6 pixels (6 Y + 3 Cb + 3 Cr).
// SMPTE RP 219-1 Color Bar Pattern Generator
// 10-bit Y'CbCr packed as v210 (4:2:2). Compliant with SMPTE RP 219-1:2014
struct Params {
width: u32,
@@ -11,8 +11,8 @@ struct Params {
@group(0) @binding(0) var<storage, read_write> out: array<u32>;
@group(0) @binding(1) var<uniform> params: Params;
fn bar_index(px: u32) -> u32 {
return min((px * 7u) / params.width, 6u);
fn bar_index(px: u32, bars_75_width: u32) -> u32 {
return min((px * 7u) / bars_75_width, 6u);
}
@compute @workgroup_size(64)
@@ -24,25 +24,109 @@ fn main(@builtin(global_invocation_id) gid: vec3<u32>) {
}
let x = (block * 6u) % params.width;
let y_px = (block * 6u) / params.width;
// Bar order: 75% white, yellow, cyan, green, magenta, red, blue
// 75% Color Table: white, yellow, cyan, green, magenta, red, blue
let y_tab = array<u32, 7>(721u, 674u, 581u, 534u, 251u, 204u, 111u);
let cb_tab = array<u32, 7>(512u, 176u, 589u, 253u, 771u, 435u, 848u);
let cr_tab = array<u32, 7>(512u, 543u, 176u, 207u, 817u, 848u, 481u);
// Layout calculations mapping the 4:3 area centered in a 16:9 canvas
let bars_width: u32 = (params.height / 3u) * 4u;
let bars_start: u32 = (params.width - bars_width) / 2u;
let bars_end: u32 = bars_width + bars_start;
let one_bar_width: u32 = bars_width / 7u;
// Strict vertical boundary calculations based on 12th parts
let unit_h: u32 = params.height / 12u;
let bound_s1: u32 = unit_h * 7u; // Row 630 on 1080p
let bound_s2: u32 = bound_s1 + unit_h; // Row 720 on 1080p
let bound_s3: u32 = bound_s2 + unit_h; // Row 810 on 1080p
// Section 3 Linear Y-Ramp boundaries
let ramp_start = bars_start + one_bar_width;
let ramp_end = bars_end;
let ramp_width = ramp_end - ramp_start;
var y: array<u32, 6>;
var cb: array<u32, 6>;
var cr: array<u32, 6>;
for (var i = 0u; i < 6u; i++) {
let b = bar_index(x + i);
let px_x = x + i;
// SECTION 1 (Top 7/12): Main 75% Color Bars
if (y_px < bound_s1) {
if (px_x >= bars_start && px_x < bars_end) {
let b = bar_index(px_x - bars_start, bars_width);
y[i] = y_tab[b];
cb[i] = cb_tab[b];
cr[i] = cr_tab[b];
} else {
// 40% Gray Flanks
y[i] = 414u; cb[i] = 512u; cr[i] = 512u;
}
}
// SECTION 2 (Next 1/12): 100% Cyan, -I Signal, 75% White, 100% Blue
else if (y_px >= bound_s1 && y_px < bound_s2) {
if (px_x < bars_start) {
y[i] = 754u; cb[i] = 615u; cr[i] = 64u; // 100% Cyan
} else if (px_x >= bars_start && px_x < ramp_start) {
y[i] = 244u; cb[i] = 612u; cr[i] = 395u; // -I Signal
} else if (px_x >= bars_end) {
y[i] = 127u; cb[i] = 960u; cr[i] = 471u; // 100% Blue
} else {
y[i] = 721u; cb[i] = 512u; cr[i] = 512u; // 75% White
}
}
// SECTION 3 (Next 1/12): 100% Yellow, +Q Signal, Linear Y-Ramp, 75% Red
else if (y_px >= bound_s2 && y_px < bound_s3) {
if (px_x < bars_start) {
y[i] = 877u; cb[i] = 64u; cr[i] = 553u; // 100% Yellow
} else if (px_x >= bars_start && px_x < ramp_start) {
y[i] = 141u; cb[i] = 697u; cr[i] = 606u; // +Q Signal
} else if (px_x >= bars_end) {
y[i] = 250u; cb[i] = 409u; cr[i] = 960u; // 75% Red
} else {
// Perfect linear scaling from Digital Black (64u) to Digital White (940u)
let clamped_x = clamp(px_x, ramp_start, ramp_end);
y[i] = 64u + ((clamped_x - ramp_start) * (940u - 64u)) / ramp_width;
cb[i] = 512u;
cr[i] = 512u;
}
}
// SECTION 4 (Bottom 3/12): Pluge Panel Calibration Blocks
else {
if (px_x >= bars_start && px_x < bars_end) {
let b = (px_x - bars_start) / one_bar_width;
if (b == 0u || b == 2u || b >= 4u) {
y[i] = 64u; cb[i] = 512u; cr[i] = 512u; // 0% Black
} else if (b == 1u) {
y[i] = 940u; cb[i] = 512u; cr[i] = 512u; // 100% White Calibration
} else if (b == 3u) {
// PLUGE Sub-bar generation (Split into 3 absolute equal fragments)
let sub_bar_offset = (px_x - bars_start) % one_bar_width;
let sub_b = (sub_bar_offset * 3u) / one_bar_width;
cb[i] = 512u;
cr[i] = 512u;
if (sub_b == 0u) {
y[i] = 46u; // -2% Sub-Black
} else if (sub_b == 1u) {
y[i] = 64u; // 0% Black
} else {
y[i] = 82u; // +2% Above-Black
}
}
} else {
// 15% Gray Flanks
y[i] = 195u; cb[i] = 512u; cr[i] = 512u;
}
}
}
// v210 word layout, chroma co-sited with luma samples 0/2/4:
// w0 = Cb0|Y0<<10|Cr0<<20; w1 = Y1|Cb2<<10|Y2<<20;
// w2 = Cr2|Y3<<10|Cb4<<20; w3 = Y4|Cr4<<10|Y5<<20
// Packing into standard v210 10-bit macroblock layout words
out[block * 4u + 0u] = (cb[0] & 0x3FFu) | ((y[0] & 0x3FFu) << 10u) | ((cr[0] & 0x3FFu) << 20u);
out[block * 4u + 1u] = (y[1] & 0x3FFu) | ((cb[2] & 0x3FFu) << 10u) | ((y[2] & 0x3FFu) << 20u);
out[block * 4u + 2u] = (cr[2] & 0x3FFu) | ((y[3] & 0x3FFu) << 10u) | ((cb[4] & 0x3FFu) << 20u);