sharpemu/docs/bink2-bridge.md

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 bridge 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 through the bundled FFmpeg-backed native bridge (native/bink2-bridge/sharpemu_bink2_bridge.c); see "Supplying the adapter" below for where that binary comes from. 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 forces a host FFmpeg source. SharpEmu searches SHARPEMU_FFMPEG_PATH, the executable directory, its ffmpeg subdirectory, and then PATH. The FFmpeg build must contain the Bink 2 decoder; stock FFmpeg builds that only recognize the Bink container are not sufficient.

Supplying the adapter

The adapter (native/bink2-bridge/sharpemu_bink2_bridge.c) links against a custom FFmpeg build (github.com/sharpemu/ffmpeg-core, LGPL-2.1) that adds a Bink 2 decoder to FFmpeg 7.1.2; no proprietary RAD SDK is needed to build or run SharpEmu.

dotnet publish builds it from source with CMake + Ninja + clang-cl (Windows) or the platform's default C compiler (Linux/macOS), targeting win-x64, linux-x64, osx-x64, or osx-arm64, then embeds the result in the published single-file executable. Publishing SharpEmu therefore requires that toolchain locally (the same one the CI runners already ship with); there is no prebuilt/download fallback. A downloaded release needs no such setup: the compiled adapter is already inside SharpEmu.exe.

To use a different build of the adapter, point to it explicitly:

SHARPEMU_BINK2_BRIDGE=/absolute/path/sharpemu_bink2_bridge.dll \
  ./SharpEmu /path/to/eboot.bin

The expected exports are sharpemu_bink2_open_utf8, sharpemu_bink2_open_scaled_utf8, sharpemu_bink2_decode_next_bgra, and sharpemu_bink2_close. The adapter opens one movie, optionally scaling it down to a maximum size, exposes BGRA pixels, and advances after each decoded frame. The managed side validates dimensions and retains ownership of the destination buffer.

If the bridge is absent in native mode, SharpEmu logs one informational line and retains the existing guest rendering path.