# Bink 2 bridge Demon's Souls plays Bink 2 (.bk2) files through a Bink implementation linked directly into eboot.bin. It does not use libSceVideodec, therefore an HLE video decoder cannot observe or replace those frames. SharpEmu observes successful guest .bk2 opens and, when a Bink decoder is available, presents its decoded BGRA frames at the normal guest-flip boundary. This preserves the game's own timing and lets the host Vulkan presenter display the movie without trying to execute the PS5-specific Bink GPU decode path. The default path decodes by calling FFmpeg's own C API directly from managed code (`src/SharpEmu.Libs/Bink/FfmpegNativeBinkFrameSource.cs`, via the [FFmpeg.AutoGen](https://github.com/Ruslan-B/FFmpeg.AutoGen) P/Invoke bindings) against a custom FFmpeg build (`github.com/sharpemu/ffmpeg-core`, LGPL-2.1) that adds a Bink 2 decoder to FFmpeg 7.1.2; see "Supplying the FFmpeg libraries" below for where those libraries come from. No proprietary RAD SDK is needed to build or run SharpEmu, and there is no C/C++ code of SharpEmu's own involved in decoding -- SharpEmu.CLI.csproj only downloads a prebuilt release archive. Set `SHARPEMU_BINK_MODE=guest` to leave decoding to the Bink implementation statically linked into the game instead. Set `skip` only when explicitly testing a title whose cinematics are optional. Set SHARPEMU_BINK_MODE=dummy to retain the open and show a built-in, non-decoded placeholder frame. This requires no SDK, but is a visual diagnostic only; it does not decode the movie or alter its game logic. SHARPEMU_BINK_MODE=native is equivalent to the default and mainly useful for being explicit about it. The experimental `SHARPEMU_BINK_MODE=ffmpeg` override is unrelated to the default path above: instead of calling into FFmpeg in-process, it spawns a standalone `ffmpeg` executable and reads raw frames from its stdout (`src/SharpEmu.Libs/Bink/FfmpegBinkFrameSource.cs`). SharpEmu searches `SHARPEMU_FFMPEG_PATH`, the executable directory, its `ffmpeg` subdirectory, and then `PATH` (plus a couple of common Homebrew paths on macOS). That `ffmpeg` build must contain a Bink 2 decoder itself; a stock FFmpeg build that only recognizes the Bink container is not sufficient. Most users want the default `native` mode instead, which always has Bink 2 support since it's built against `ffmpeg-core` specifically. ## Supplying the FFmpeg libraries `dotnet publish` fetches a prebuilt release of `github.com/sharpemu/ffmpeg-core` (the tag is pinned in `SharpEmu.CLI.csproj`'s `FfmpegRuntimeTag`, matched to the `FFmpeg.AutoGen` package version in `Directory.Packages.props` -- both need to agree on the same FFmpeg ABI) and copies its dynamically linked libraries into a `plugins` folder next to the published executable. No C toolchain is required to build SharpEmu; publishing just downloads a zip. `plugins` is a loose, unpacked folder rather than something embedded in the single-file bundle, so the OS loader can resolve the libraries' own inter-dependencies (`avcodec` depends on `avutil`, etc.) itself. A plain `dotnet publish` with no `-r` still works: it defaults to the host machine's own RID (see `Directory.Build.props`), so it fetches the matching `ffmpeg-core` archive and populates `plugins` without any extra flags. Passing an explicit `-r ` (e.g. to cross-publish `linux-x64` from Windows) still overrides that default normally. To use a different set of FFmpeg libraries, drop them into the published `plugins` folder yourself (matching FFmpeg's own file-naming and versioning conventions, e.g. `avformat-61.dll` / `libavformat.so.61` / matching `.dylib`) -- `FfmpegNativeBinkFrameSource` points `ffmpeg.RootPath` at that folder and does not otherwise care where the files came from. If the libraries are absent or fail to load, `FfmpegNativeBinkFrameSource.TryOpen` degrades gracefully: SharpEmu logs one informational line ("Bink2 bridge could not open movie ...") and leaves the guest's own rendering path untouched, rather than crashing.