iptvnator/tools/embedded-mpv/README.md

Embedded MPV Runtime

This directory owns the source builders, staging, manifests, and archive helpers for IPTVnator's experimental Embedded MPV runtime.

The Linux architecture has a strict process boundary:

• Electron, embedded_mpv.node, and embedded_mpv_frame_reader.node must not load or link libmpv.
• Native-view starts a separate system mpv --wid process.
• Frame-copy starts iptvnator_mpv_helper; only that helper may link libmpv.

Do not weaken this boundary to simplify packaging. A missing helper/runtime must make frame-copy unavailable and leave native-view as the safe x64 fallback.

Runtime Policy

Release builds use an LGPL-compatible, dynamically linked runtime:

• FFmpeg is built without --enable-gpl and --enable-nonfree.
• mpv is built with -Dlibmpv=true and -Dgpl=false.
• Bundled libraries remain individually replaceable under native/lib.
• Exact source URLs, versions, checksums or git commits, submodules, licenses, build flags, local patches, and build scripts are published with the release.

Homebrew mpv is local-development-only. It requires IPTVNATOR_EMBEDDED_MPV_ALLOW_HOMEBREW=1, and release validation rejects it.

Generated Layout

vendor/embedded-mpv/
  darwin-arm64/
    include/mpv/client.h
    lib/*.dylib
    runtime-manifest.json
  darwin-x64/
    include/mpv/client.h
    lib/*.dylib
    runtime-manifest.json
  win32-x64/
    include/mpv/client.h
    lib/libmpv-2.dll        # accepted basename variants are preserved
    lib/libmpv.dll.a        # or an MSVC import library
    runtime-manifest.json
  linux-x64/
    include/mpv/client.h
    lib/libmpv.so
    lib/libmpv.so.2
    lib/<declared closure>
    notices/embedded-mpv-notices.json
    notices/THIRD_PARTY_NOTICES.txt
    notices/licenses/<package>/<upstream path>
    runtime-manifest.json

These directories are generated release inputs and are ignored by git. runtime-manifest.json is the profile-neutral source/build manifest. Packaging writes a normalized embedded-mpv-runtime.json beside the native artifacts. Bundled Linux profiles flatten the three notice entries from notices/ into that same native directory; system and marker-only profiles remove them.

Building And Staging

Stage an existing compatible prefix with:

pnpm embedded-mpv:stage-runtime -- darwin arm64 /path/to/prefix
pnpm embedded-mpv:stage-runtime -- darwin x64 /path/to/prefix
pnpm embedded-mpv:stage-runtime -- win32 x64 /path/to/prefix
pnpm embedded-mpv:stage-runtime -- linux x64 /path/to/prefix

Build the pinned macOS or Linux source runtime first when no prefix exists:

pnpm embedded-mpv:build-runtime -- arm64 /tmp/macos-prefix
pnpm embedded-mpv:stage-runtime -- darwin arm64 /tmp/macos-prefix

pnpm embedded-mpv:build-runtime:linux -- /tmp/linux-prefix
pnpm embedded-mpv:stage-runtime -- linux x64 /tmp/linux-prefix

The Linux builder runs only on Linux x64. It requires the tool versions and system development interfaces declared in build-linux-runtime.cjs, including Meson 1.6 or newer, gperf 3.1 or newer, Ninja, CMake, NASM, pkg-config, patchelf, and readelf. It builds into an owned staging directory and publishes atomically, so it will not delete or overwrite an arbitrary destination.

The pinned Linux source stack currently includes FFmpeg 8.1, mpv 0.41.0, libplacebo 7.360.1, libass 0.17.3, FreeType 2.13.3, FriBidi 1.0.16, HarfBuzz 8.5.0, Expat 2.8.2, Fontconfig 2.16.0, OpenSSL 3.5.7, hwdata 0.409, and libdisplay-info 0.1.1. The builder stages a private pinned pnp.ids/hwdata.pc; libdisplay-info is not allowed to consume the build host's /usr/share/hwdata.

Before publication, the Linux builder verifies:

• every archive digest and git/submodule commit;
• the exact FFmpeg/mpv flags and LGPL policy;
• an exact libmpv.so.2 SONAME and complete reachable shared-library closure;
• $ORIGIN RUNPATHs with no build-prefix paths or undeclared host fallback;
• the external system-library allowlist;
• GLIBC_2.35 and GLIBCXX_3.4.30 ABI ceilings;
• file hashes, byte sizes, build inputs, licenses, and source obligations.

Linux Package Profiles

Set one exact IPTVNATOR_LINUX_FRAME_COPY_PROFILE per packaging pass:

Profile	Formats	Runtime handling
system	DEB, RPM, Pacman	Remove native/lib; require libmpv2, mpv-libs, or mpv
portable	AppImage, Snap	Retain the pinned LGPL closure under native/lib
flatpak	Flatpak	Retain the same pinned LGPL closure under native/lib

The DEB metadata requires libmpv2 and is release-tested on Ubuntu 24.04 (Noble). Ubuntu 22.04 (Jammy) only provides libmpv1; use the x64 AppImage on that distribution rather than relaxing the runtime contract.

The strict Snap retains Electron Builder's default plugs and adds an auto-connected private shared-memory plug. This supplies a snap-specific POSIX shm namespace without granting global cross-snap shared-memory access.

The bounded probe and every playback helper share one sanitized loader environment derived from the validated, cached runtime mode. Ambient LD_PRELOAD and LD_LIBRARY_PATH are removed. System packages then use the default loader; bundled packages put their validated native/lib first. AppImage and Flatpak use normal host/sandbox lookup for the declared external interfaces. In a genuine Snap mount, filtered SNAP_LIBRARY_PATH GL roots under /var/lib/snapd/lib/gl come next, ahead of generic $SNAP library and x64 multiarch roots, so host GL/NVIDIA dispatch cannot be shadowed by snap-staged generic GL libraries. A Linux session without the validated cached mode is rejected before spawn.

Profiles cannot share one Electron Builder pass because its targets reuse the same unpacked application directory. A missing or unsupported profile, or a target from another profile, fails packaging.

Linux frame-copy release artifacts are x64-only. Non-x64 packages are always marker-only even if environment variables point at the x64 staged runtime.

Build Integration

apps/electron-backend/build-embedded-mpv.js builds the addon, frame reader, and helper against the staged inputs. On Linux it links the helper to the verified staged libmpv path rather than a generic host -lmpv, then checks with readelf that:

• the helper has exactly the declared libmpv DT_NEEDED;
• the helper RUNPATH is $ORIGIN/lib;
• the addon and frame reader have no libmpv dependency;
• no runtime dependency contains an absolute/build-prefix loader path.

The package hook copies native artifacts into app.asar.unpacked/electron-backend/native/, selects the system or bundled layout, restores exact file modes, writes the packaged manifest, and validates the bundled legal payload. AppImage, Snap, and Flatpak receive embedded-mpv-notices.json, THIRD_PARTY_NOTICES.txt, and licenses/<package>/**; DEB, RPM, Pacman, and marker-only packages must not retain them. Package validation also scans the Electron executable and all shipped Electron libraries for a direct libmpv dependency.

At startup, Linux x64 frame-copy is advertised only after the main process validates that manifest/files and successfully executes:

iptvnator_mpv_helper --runtime-probe

The bounded probe initializes idle libmpv plus EGL/OpenGL and mpv render contexts, then creates, maps, validates, and destroys a minimal 16x16 shared-memory ring named /impv-fc-runtime-probe-<pid>. It does not open media or enter media/command loops. A timeout, loader failure, malformed protocol, missing file, hash mismatch, unusable graphics path, or shm lifecycle failure returns a stable reason and keeps the BrowserWindow sandbox enabled. The installed-Snap probe therefore tests the private shared-memory confinement needed by playback rather than only loader and graphics startup.

CI And Source Distribution

Linux CI builds or restores the pinned source runtime once, then packages and verifies system, portable, and flatpak independently. Every artifact is extracted for manifest, mode, package-metadata, ELF-isolation, and helper-probe checks. System formats are probed after their declared dependency is installed; Snap and Flatpak also require a sandboxed probe where the runner supports it.

The Linux runtime cache contains only staged headers/libraries/manifest plus immutable source inputs: exact downloaded archives (including hwdata), a clean recursive libplacebo checkout, and collected license files. It never caches finished notices or the compliance tarball. After either a build or cache hit, CI revalidates those inputs, regenerates vendor/embedded-mpv/linux-x64/notices for the current runtime manifest, and creates linux-frame-copy-runtime-sources.tar.xz for the current repository revision/diff. Before archiving, the clean cached libplacebo checkout is converted into a non-dereferenced working-tree snapshot with every .git entry removed; the validated main/submodule commits remain in the source index.

That source-compliance archive uses normalized tar metadata and contains the exact unique archive hash set, VCS-free libplacebo sources and recursive submodules, license inputs, generated notices, runtime/source index metadata, and the builder, stager, manifest, notice-generator, and source-snapshot code. The notice generator rejects missing, undeclared, symlinked, size-mismatched, or hash-mismatched license files.

Snap publication is a separate release.published workflow for public v* GitHub releases. It verifies that the public release already contains at least one Snap and exactly one non-empty linux-frame-copy-runtime-sources.tar.xz before uploading any Snap to the Store's edge channel.

Windows CI stages a checksum-pinned x64 LGPL archive. The DLL basename encoded in its import library is preserved and must be present beside iptvnator_mpv_helper.exe. Tagged releases require explicit repository configuration; the public fallback is for non-tag artifacts only.

Local Development

Linux can use distribution development packages for an unshipped local build (libmpv-dev, EGL/OpenGL/GBM development files, and X11 headers). Overrides: LIBMPV_INCLUDE_DIR and LINUX_NATIVE_LIBRARY_DIR. Required/release package builds must use the pinned staged runtime and manifest.

On macOS:

pnpm run serve:backend:embedded-mpv

This explicitly permits Homebrew for the local native build and enables the experiment. It is not a release path.

See docs/architecture/embedded-mpv-native.md for the runtime capability, fallback, controls, and packaged-release contracts.