SDR vs HDR
Unlike most media players, QCView does not tonemap media. Other players make assumptions about color space that are at least partially wrong — or at minimum, inconvenient for a professional review workflow.
As a result, video output is presented in the display’s working color space. In SDR mode, this is sRGB, so SDR video displays correctly without any adjustment. In HDR mode, the display assumes Rec.2100 PQ (Windows/Linux) or Linear sRGB/P3 EDR (MacOS), to match OS expectations for HDR.
Interface Tonemapping
When HDR is active, the UI elements need to be tonemapped into the HDR color space. QCView provides an adjustable target nits setting to control how bright the interface appears relative to the HDR content. This lets you balance UI readability against the HDR luminance.
Color Output with OCIO
SDR Mode
In SDR mode, use an sRGB output node for a standard display-referred result. If you want to preview how content will look on a typical consumer display — ~Rec.709 / Gamma 2.4 — any Rec.1886 option will work. (Given the general state of video color management on consumer hardware, this is how most viewers will see your content.)
HDR Mode (Windows)
With Windows HDR mode enabled, you can present video in Rec.2100 PQ. To view SDR content in this mode, use the appropriate Display node to transform it into that space.
HDR Mode (macOS — EDR)
macOS uses Extended Dynamic Range (EDR) instead of PQ/ST.2084. EDR is a linear-light system where 1.0 = SDR white and values above 1.0 map to brighter HDR highlights, up to the display’s maximum headroom.
To use EDR in QCView:
- Enable EDR from the HDR menu in the menu bar
- Select an EDR colorspace: Linear sRGB or Linear Display P3 (match to your display)
- In the Color node editor, select a Linear sRGB EDR or Linear P3 EDR display with an ACES 2.0 HDR view (500 / 1000 / 2000 / 4000 nits)
The ACES 2.0 HDR views produce tone-mapped output scaled to specific peak luminance levels. For example, the 1000 nit view outputs values up to 10.0 (1000 / 100 nit reference white). The display’s EDR headroom determines how much of this range is visible.
The Standard (No Tonemap) view passes scene-linear values through without tone mapping — useful for viewing EXR data directly on an EDR display.
Note: EDR requires an Apple Silicon Mac with macOS 13.0 or later. The maximum EDR headroom depends on the display hardware (typically 2x-8x for built-in MacBook displays, higher for Pro Display XDR).
HDR Mode (Linux)
On Linux, HDR output can be toggled on and off within QCView at runtime. However, HDR must also be enabled at the display/compositor level — for example, in KDE Plasma’s Display settings — for HDR output to reach the monitor.
When HDR is enabled, the Vulkan swapchain switches to A2B10G10R10 with HDR10_ST2084 color space. The ImGui interface is converted to PQ via a GPU shader, with configurable target nits for UI brightness.
Note: Linux HDR support is experimental and has been tested on Kubuntu with KDE Plasma 6 (Wayland).