SMPTE RP219-1 pattern signal

cmd/mxl-pattern/main.go

@@ -192,16 +192,22 @@ type pattern struct {
 var patterns = map[string]pattern{
 	"bars": {
 		name:        "bars",
-		description: "SMPTE 75% color bars",
+		description: "75% color bars",
-		kernelPath:  "kernels/static/smpteBars.wgsl",
+		kernelPath:  "kernels/static/colorBars.wgsl",
 		motion:      false,
 	},
 	"bars-move": {
 		name:        "bars-move",
-		description: "SMPTE 75% color bars with moving square",
+		description: "75% color bars with moving square",
-		kernelPath:  "kernels/dynamic/smpteBars.wgsl",
+		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

@@ -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
+// NewTextOverlay rasterizes text (white, anti-aliased) onto a black backing box.
-// box, centered horizontally. Box width and x are multiples of 6 so the 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/static/colorBars.wgsl

@@ -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

@@ -1,5 +1,5 @@
-// 75% SMPTE color bars, Rec.709, 10-bit Y'CbCr, packed as v210 (4:2:2).
+// SMPTE RP 219-1 Color Bar Pattern Generator
-// One work-item per 16-byte block = 6 pixels (6 Y + 3 Cb + 3 Cr).
+// 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 {
+fn bar_index(px: u32, bars_75_width: u32) -> u32 {
-    return min((px * 7u) / params.width, 6u);
+    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:
+    // Packing into standard v210 10-bit macroblock layout words
-    // 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);