HDRScopes

**Real-time video scopes for the live Windows HDR signal.** Waveform · Histogram · Vectorscope · CIE Chromaticity — reading the actual scRGB FP16 pixels Windows composites to your display.

Traditional scopes live inside an NLE and only see that app's own timeline. HDRScopes instead captures the Windows desktop itself (DXGI Desktop Duplication, scRGB FP16 — the real composited HDR signal), so it can measure what nothing else can: games, video players, YouTube in a browser, your own code, another grading app such as Unreal Engine or Lightroom / Adobe Camera Raw, or simply the desktop as a whole. If Windows draws it in HDR, HDRScopes can put it on a scope — live, at ~110 FPS for a 4K capture.

_{Colorized RGB waveform of a live 4K HDR feed on the 0–10,000-nit log axis. Circles: the hover probe marking the pixel under the cursor.}

Scopes

• Waveform — per-column PQ-nit histogram over a fixed 0–10,000 nit log axis. Luminance or RGB mode, optional colorize, extents display (colored points or a supersampled 1-px envelope line), draggable custom reference lines, and an SDR-white vertical-zoom mode that pins the axis top to the current Windows SDR-white level.
• Histogram — pixel count per nit bin: stacked L/R/G/B bands, overlaid RGB, or luma only.
• Vectorscope — Y′CbCr chroma in your choice of PQ (HDR, absolute-nits) or Rec.709 (SDR) encoding, with 75%/100% primary/secondary targets and a skin-tone line.
• CIE Chromaticity — 1931 xy or 1976 u′v′, with the spectral locus, Rec.709 / P3 / Rec.2020 gamut triangles, and the D65 white point.

Layouts: single scope, 2-up, or 4-up, each panel with its own scope choice and settings. Hover any pixel of the captured screen and each scope marks where that pixel lands (white = luminance, R/G/B circles), with a nit readout at the cursor.

_{The 4-up layout reading one live frame — waveform, CIE chromaticity, histogram, and vectorscope, with the hover probe marking the same screen pixel in every panel.}

Download

Grab the latest zip from Releases, unzip anywhere, run HDRScopes.exe. No installer, no dependencies, no telemetry. Fully portable: settings persist to a plain-text settings.ini next to the exe, so deleting the folder removes every trace, and separate copies of the app can keep separate setups. (If the folder isn't writable — e.g. Program Files — settings fall back to %LOCALAPPDATA%\HDRScopes.)

On startup the app asks github.com whether a newer release exists and shows a small notice if so — nothing is sent beyond the request itself, nothing is installed automatically, and the check can be turned off under Controls > Preferences.

Requirements: Windows 10 (1809+) or Windows 11 · any DX11-capable GPU · HDR or SDR output. SDR signals (an SDR desktop, or SDR content on an HDR desktop — same thing to the capture) are read the HDR-compatible way, as the 0–80-nit reference range, and the scopes fully support working there: the waveform supports an SDR-white zoom, the hover readout shows 8-bit SDR values, and the vectorscope supports Rec.709 (SDR) encoding. The one thing missing is SDR-relative nit labels on the graticules — ask in Issues if you need that.

Usage

• Controls (top-right button) opens the settings popup: capture source (monitor / window / dragged screen region), quality, and per-panel scope options. Rest the mouse on any control for an explanation (tooltips can be turned off under Preferences); right-click any control to reset just it.
• Layouts — the 1 / 2 / 4 buttons switch layout presets; each panel has a scope picker.
• Navigate — mouse-wheel zoom (to cursor), middle-drag pan, click the top-right zoom readout to reset.
• Reference lines — add draggable horizontal nit markers on the waveform (log-scaled drag, Shift = finer).
• Quality — presets from Low to Per-pixel trade bin-grid and sample density for speed; optional bilinear source downsample suppresses nearest-sampling noise; optional FPS limiter.
• The UI is drawn at the Windows SDR-white brightness on HDR outputs, while the scope traces keep their true HDR nit values.

Known limitations

• No parade scope yet, as I never personally found it useful — but I can add it if someone wants it.
• The vectorscope skin-tone line follows the classic "I-line" convention, for which no exact standard exists — tools disagree slightly on its angle, so ours is configurable (skin tones of all complexions naturally cluster along this line, varying in saturation far more than in hue).
• RGB undershoots below 0 nits clamp to the bottom of the waveform rather than rendering below the 0-line.
• DRM-protected content (Netflix and friends) captures as black — that's Windows working as intended, not a bug.

Building from source

Visual Studio 2022 (or Build Tools) + CMake:

cmake -S . -B build -G "Visual Studio 17 2022" -A x64
cmake --build build --config Release

Output: build/Release/HDRScopes.exe (static CRT, fully self-contained). Shaders compile at runtime, so .hlsl edits apply on relaunch with no rebuild. Architecture notes live in docs/ARCHITECTURE.md.

License & credits

GPLv3 — see LICENSE. Third-party components are MIT-licensed; see THIRD_PARTY_NOTICES.md.

• Color-space conversion HLSL adapted from SKIV by Andon "Kaldaien" Coleman and Aemony (MIT) — thank you.
• UI built on Dear ImGui (MIT).
• Scope behavior is modeled on the industry-standard scopes in DaVinci Resolve and validated against them where possible.
• Developed in close AI pair-programming with Anthropic's Claude — the scope design, color-science decisions, and validation are human.

Support

Bug reports and feature requests are welcome in Issues — this is a hobby project, so support is best-effort. If HDRScopes is useful to you, a star helps others find it, and a donation via Ko-fi or the Sponsor button up top is appreciated but never expected.

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_{Real-world use: HDRScopes on a secondary display, analyzing a Cyberpunk 2077 RenoDX HDR setup. This screenshot is an HDR AVIF with gain map — in a supporting browser on an HDR display, it displays in true HDR.}