@ffmpeg/core 0.12.10 source/build material

Release: ffmpeg.wasm v12.15, commit 71aa99d37c02a7b4c435275ca9ef50e612f6efa1.
The packages/core/package.json in this release declares version 0.12.10.
The runtime binary is unmodified from that npm package.

1. Download all source archives listed in manifest.json.
2. Extract ffmpeg.wasm.tar.gz and the library archives.
3. The ffmpeg.wasm Dockerfile records each library revision/tag and the Emscripten emsdk:3.1.40 toolchain. Build scripts and bindings are included in that archive.
4. To compile the single-thread production core with the upstream build system, run 'make prd' inside ffmpeg.wasm using Docker buildx and make. This requires downloading the base toolchain image and build tools.
5. To use the supplied library snapshots instead of remote Git refs, replace the corresponding Dockerfile ADD Git URL /src instructions with COPY <extracted-library-directory> /src, and replace the zimg git clone instruction in the same way. Keep each existing build/<library>.sh COPY and RUN step. The manifest records the archive commit identities, including mutable upstream branch snapshots.
6. Emscripten 3.1.40 and its SDL2 port source are supplied. sdl2-port.py.txt records the toolchain port metadata.

The package has not been rebuilt here; no bit-for-bit reproducibility or independent legal clearance is asserted. Source archives include their original notices and full license files.