Add Player > External Monitor > Preview Window (HDR)

[ddennedy]

• Replaces custom GPU shaders/integrations with Qt Quick Multimedia's VideoOutput with a custom QVideoSink based on MLT.
• That makes external monitor with system display work again plus more.
• Adds Preview Window (HDR) to External Monitor sub-menu. As a QQuickView (window) separate from the widgets-based MainWindow, Quick can support HDR.
  • This window is not only useful for HDR. Some might like it over the other system display options because fullscreen is optional but also filter overlays are still in the main window.
  • HDR is working for me on macOS and Windows but not yet Linux.
  • Keyboard shortcut Ctrl+` opens or raises it if already open (convenient for single screen).
• Move the External Monitor sub-menu to the Player main menu so it is more convenient.
• Adds Dynamic range to the Add Custom Video Mode dialog: SDR, HLG HDR, or PQ HDR. Automatic video mode also adapts to HDR.
• HDR editing requires:
  • Native 10-bit CPU or Linear 10-bit GPU/CPU processing modes, and
  • filters tagged with #gpu or #10bit.
• You cannot switch between different HDR systems (HLG vs. PQ) within the same app session. You can freely switch between SDR and a single HDR, however. There is nothing in place to enforce this, but the video is visually obvious when you need to restart.
• Export automatically encodes HDR per the video mode assuming you stick with the default 10-bit preset or choose another compatible one.
• Added an Export > Codec > HDR... button to set PQ HDR metadata, which only works for the libx265 and libsvtav1 codecs. A post-processing step to inject metadata for hardware encoders is pending, e.g.

ffmpeg -i output_temp.mp4 -c copy -metadata:s:v:0 master_display="G(13250,34500)B(7500,3000)R(34000,16000)WP(15635,16450)L(10000000,1)" -max_cll "1000,400" output_final.mp4

• Adds Settings > Display Method > Vulkan for Linux and removes the non-functional "Software (Mesa)" option.
• Special note for Linux/BSD build: the default media backend for Qt now is FFmpeg. If you are building your own FFmpeg, then it will likely be incompatible with Qt's. Likewise, if you are installing binary Qt from upstream (qt.io), then your build of MLT might be using a different version of FFmpeg than the version included with Qt for its media backend. Due to these complications, and the fact that Shotcut does not need a fully operational Qt Multimedia backend on Linux (it uses MLT) there is now a MinimalMediaBackend library build target. You can opt into it with cmake configure option -DBUILD_MINIMAL_MEDIA_BACKEND=ON. Shotcut needs Qt Multimedia on Linux/BSD now (previously it did not) because it must be able to make a custom, MLT-based QVideoSink to feed the QML Quick Multimedia-based video component. After building, you need to manually install it like:
  cp -p build/MinimalMediaBackend/libminimalmediaplugin.so ~/Qt/6.10.3/gcc_64/plugins/multimedia/

[Copilot]

Pull request overview

This PR replaces the custom GPU-backed preview rendering path with Qt Multimedia VideoOutput/QVideoSink, adds an HDR-capable external preview window, and extends video mode/export settings for HDR transfer metadata.

Changes:

• Adds HDR preview window UI, frame delivery through QVideoFrame, HDR gain handling, and platform/build support for Qt Multimedia.
• Adds dynamic range selection/display for custom video modes and timeline properties.
• Adds HDR export metadata UI/injection and updates packaging/build scripts for newer Qt and multimedia/QML dependencies.

Reviewed changes

Copilot reviewed 45 out of 46 changed files in this pull request and generated 18 comments.

Show a summary per file

File	Description
src/widgets/timelinepropertieswidget.ui	Adds dynamic range display row.
src/widgets/timelinepropertieswidget.cpp	Populates dynamic range from MLT transfer characteristics.
src/widgets/openglvideowidget.h	Removes OpenGL preview widget declaration.
src/widgets/openglvideowidget.cpp	Removes OpenGL shader preview implementation.
src/widgets/metalvideowidget.h	Removes Metal preview widget declaration.
src/widgets/metalvideowidget.mm	Removes Metal preview implementation.
src/widgets/d3dvideowidget.h	Removes D3D preview widget declaration.
src/widgets/d3dvideowidget.cpp	Removes D3D preview implementation.
src/videowidget.h	Adds Qt Multimedia sink/frame APIs and HDR transfer signal.
src/videowidget.cpp	Implements frame-to-QVideoFrame conversion, HDR color metadata, and sink delivery.
src/util.h	Declares AVX2 CPU feature helper.
src/util.cpp	Implements AVX2 detection.
src/settings.h	Adds HDR preview/settings accessors.
src/settings.cpp	Persists HDR preview geometry and HDR display/tone mapping settings.
src/qml/views/HdrPreview.qml	Adds HDR preview window UI and controls.
src/qml/views/hdr_gain.frag	Adds shader for HDR gain adjustment.
src/qml/modules/Shotcut/Controls/VuiBase.qml	Adds main preview VideoOutput sink.
src/mltcontroller.h	Adds transfer-characteristic state accessors.
src/mltcontroller.cpp	Loads/detects HDR transfer characteristics from profiles/producers.
src/mainwindow.ui	Moves External Monitor menu and adds Vulkan drawing action.
src/mainwindow.h	Adds HDR preview window ownership and slot.
src/mainwindow.cpp	Adds HDR preview action/window wiring and drawing-method changes.
src/main.cpp	Updates Qt media/backend and graphics initialization.
src/macos.mm	Adds macOS EDR headroom helpers.
src/macos.h	Declares macOS EDR helper APIs.
src/hdrpreviewwindow.h	Adds HDR preview window class API.
src/hdrpreviewwindow.cpp	Implements HDR preview window playback, HDR gain, and platform handling.
src/docks/encodedock.ui	Adds HDR metadata button.
src/docks/encodedock.h	Adds HDR metadata state and handlers.
src/docks/encodedock.cpp	Injects HDR transfer/mastering metadata into supported encoders.
src/dialogs/customprofiledialog.ui	Adds dynamic range selector.
src/dialogs/customprofiledialog.h	Adds color-space change slot.
src/dialogs/customprofiledialog.cpp	Saves/loads HDR transfer characteristics for custom profiles.
src/CMakeLists.txt	Adds HDR preview sources, shader build step, and Qt private dependency.
scripts/build-shotcut.sh	Updates Linux/macOS packaging for Qt Multimedia and minimal backend.
scripts/build-shotcut-msys2.sh	Updates Windows Qt version and deployed Qt Multimedia/Shapes modules.
MinimalMediaBackend/minimalmediaplugin.json	Adds minimal media backend plugin metadata.
MinimalMediaBackend/minimalmediaplugin.cpp	Implements minimal Qt Multimedia backend.
MinimalMediaBackend/CMakeLists.txt	Adds build target for minimal media backend plugin.
CMakePresets.json	Updates Qt version and enables minimal media backend in preset.
CMakeLists.txt	Adds minimal backend option/subdirectory and Qt private lookup.
.github/workflows/build-windows.yml	Updates Windows CI Qt package version.
.github/workflows/build-sdk-windows.yml	Updates SDK Windows CI Qt package version.
.github/workflows/build-linux.yml	Restricts package jobs to master branch.
.github/copilot-instructions.md	Updates documented Qt version.

Comments suppressed due to low confidence (2)

src/docks/encodedock.cpp:931

• Using the MaxCLL/MaxFALL values as the gate also suppresses mastering-display metadata when both content-light fields are intentionally left as “Not set”. The dialog still collects mastering primaries and min/max luminance, so SVT-AV1 exports can silently omit mastering-display metadata even though the user configured it.

                if ((m_hdrMaxCll > 0 || m_hdrMaxFall > 0)
                    && MLT.colorTrc() == QLatin1String("smpte2084")) {

src/docks/encodedock.cpp:999

• Using the MaxCLL/MaxFALL values as the gate also suppresses master_display metadata when both content-light fields are intentionally left as “Not set”. The dialog still collects mastering primaries and min/max luminance, so exports can silently omit mastering-display metadata even though the user configured it.

                // Inject HDR10 mastering metadata for hevc_nvenc when the source is PQ.
                if (vcodec == "hevc_nvenc" && (m_hdrMaxCll > 0 || m_hdrMaxFall > 0)
                    && MLT.colorTrc() == QLatin1String("smpte2084")) {