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dtourolle bb3ab1edd7 feat(windows): mpv draws Windows video into the app window

DR-237's video half. mpv now renders Windows video the way
tauri-plugin-libmpv does on Windows: MpvBackend is handed the main
window's HWND and sets it as `wid` before mpv initialises, so mpv draws
as a child of the app window beneath the transparent WebView2, with
vo=gpu-next,gpu. osc, default bindings, VO keyboard and cursor handling
are off, so the Svelte controls drawn over the picture are the only ones.

- video_output() decides per platform (UT-274): Window(hwnd) on Windows,
  RenderApi on Linux, Off without native video. Windows with no handle
  draws nothing rather than letting mpv open a top-level window.
- native_video::enabled() is true on Windows as well, so the frontend
  takes the native path there: NativePlayerAdapter, and the page clears
  its background while video is on screen.
- enableNativeVideoCompositing() no longer logs a missing Android bridge
  as an error on the desktop, where there is no bridge to have.

Verified: every option, wid included, is accepted by the real libmpv on
Linux and by the shipped Windows DLL under wine; the Windows unit suite
passes under wine (949). Not yet seen on real Windows hardware.

2026-09-24 22:42:42 -04:00

4.6 KiB

Raw Blame History

Windows build

JellyTau targets Linux and Android primarily, but a working Windows build — including an NSIS installer cross-compiled from Linux — is produced by the Docker tooling. It is not yet a first-class release target (no code signing / CI job / SMTC lockscreen), but it runs and plays media.

How playback works on Windows

Video — mpv, drawing into the app's own window: MpvBackend is handed the main window's HWND as wid before mpv initialises and renders with vo=gpu-next,gpu as a child of it, beneath the transparent WebView2 whose page clears its background while a video is on screen (data-native-video). mpv's own controller, key bindings and cursor handling are off — the Svelte controls drawn over it are the only ones. This is the arrangement tauri-plugin-libmpv ships on Windows (same zhongfly LGPL DLL). Not yet seen on real Windows hardware — if the picture ends up over the controls, the z-order of mpv's child window is the first thing to check.
Audio — libmpv, the same MpvBackend Linux uses, with ao=wasapi. Volume, EQ, normalization and gapless all go through mpv's filter graph as on Linux. libmpv-2.dll ships beside jellytau.exe in the installer.

libmpv on Windows

Which build: zhongfly/mpv-winbuild's LGPL dev asset, pinned by name and sha256 in Dockerfile.builder, which unpacks it to /opt/libmpv-win64. Licence terms: THIRD_PARTY_NOTICES.md. The same release also carries a GPL asset (x264/x265) — do not switch to it casually, it moves the installer onto GPL-3.0 terms.
Import library: the archive only ships a MinGW libmpv.dll.a. The image generates an MSVC mpv.lib from the DLL's own mpv_* exports (llvm-readobj --coff-exports → .def → llvm-lib /def:), so it cannot name a symbol the DLL lacks.
One directory: scripts/build-windows-cross.sh copies both files into src-tauri/windows-libs/ (gitignored) before building. build.rs links mpv.lib from there and tauri.windows.conf.json bundles the DLL from there, so the DLL shipped is the one linked against. Outside the image, point LIBMPV_WIN_DIR at a directory holding libmpv-2.dll and mpv.lib.
Bumping it: change the three LIBMPV_WIN_* values together, rebuild and push the image, bump the image tag the workflows pin.

Cross-compiling from Linux (MSVC + cargo-xwin)

We use the official Tauri cross-compile path: the MSVC target (x86_64-pc-windows-msvc) driven by cargo-xwin, which downloads the MSVC CRT / Windows SDK headers and links with lld. MSVC is the target Tauri officially supports for Windows (mingw/GNU is not), and — unlike GNU — it lets the Tauri CLI bundle the NSIS installer from a Linux host.

Why not mingw/GNU? The GNU target does link a valid .exe, but the Tauri CLI gates --bundles by the host OS unless it recognizes a real Windows build. --runner cargo-xwin --target x86_64-pc-windows-msvc is what flips it into Windows mode and enables the nsis/msi bundlers on Linux.

The builder image (../Dockerfile.builder) bakes in the whole toolchain: the x86_64-pc-windows-msvc rust target, cargo-xwin, lld, llvm, nsis, and the pinned Windows libmpv.

bun run docker:build:windows            # NSIS installer + .exe -> ./dist
WIN_BUNDLES=none bun run docker:build:windows   # exe only, skip bundling

Or directly on a host that has the toolchain:

scripts/build-windows-cross.sh                    # nsis installer + exe
WIN_BUNDLES=none scripts/build-windows-cross.sh   # exe only

Under the hood the build runs:

tauri build --runner cargo-xwin --target x86_64-pc-windows-msvc --bundles nsis

Outputs:

.exe — src-tauri/target/x86_64-pc-windows-msvc/release/jellytau.exe
NSIS installer — .../release/bundle/nsis/*-setup.exe

(both copied to ./dist when OUTPUT_DIR is set).

Caveats

Cross-compilation is a last resort per Tauri's own docs — it's less tested than building on Windows. If it misbehaves, a windows-latest CI job or a Windows VM building natively (tauri build --bundles nsis) is the fallback.
Code signing is not wired up — the installer is unsigned, so Windows SmartScreen will warn on first run.

Outstanding for a first-class Windows release

SMTC (lockscreen / media keys) — not wired on Windows.
Code signing — the installer is unsigned.
First run of mpv video on real Windows hardware (DR-237).

4.6 KiB Raw Blame History