Folia FFmpeg builds

Small, static, audio-focused FFmpeg builds for the Folia Electron desktop app. This repository is derived from acoustid/ffmpeg-build and keeps its upstream variants available while adding a Folia-specific runtime contract.

The pinned FFmpeg version is 8.1.2. Builds do not enable GPL-only or nonfree components and are distributed under FFmpeg's LGPL terms. The build scripts themselves retain their MIT license.

Folia runtime contract

FFMPEG_VARIANT=folia is the default. It provides:

• audio decoding for MP3, AAC/ALAC, FLAC, Vorbis, Opus, PCM, APE, WavPack, TTA, WMA, AIFF, CAF, DSD and E-AC-3;
• DSD from both DSF (.dsf) and DSDIFF (.dff), including DST-compressed DSDIFF;
• MOV/MP4 demuxing for E-AC-3 tracks carrying the ec-3 codec tag in .m4a;
• FLAC output with PCM S16LE WAV as the compatibility fallback;
• the null muxer used by Folia to decode and validate the complete output;
• aresample for channel and sample-format conversion;
• only local file and pipe protocols, with network access disabled;
• only the ffmpeg program; ffprobe and ffplay are not bundled.

Folia's caller omits -ar for PCM and compressed sources, so the source sampling rate is preserved. A 96 kHz input therefore remains 96 kHz after transcoding. DSD is the one exception: FFmpeg decodes DSD64 at 352.8 kHz and DSD256 at 1411.2 kHz, which the FLAC encoder refuses, so Folia passes -ar 88200 for .dsf and .dff inputs.

This remains an audio-focused build. Future video processing should use a separate folia-video variant rather than silently expanding the desktop runtime binary.

Supported targets

• Linux: x86_64-linux-gnu, arm64-linux-gnu
• Windows: x86_64-w64-mingw32, aarch64-w64-mingw32
• macOS: x86_64-apple-macos10.9, arm64-apple-macos11

Build locally

ARCH=x86_64 FFMPEG_VARIANT=folia ./build-linux.sh
ARCH=x86_64 FFMPEG_VARIANT=folia ./build-windows.sh
# Requires LLVM-MinGW (aarch64-w64-mingw32-* tools) on PATH:
ARCH=aarch64 FFMPEG_VARIANT=folia ./build-windows.sh
TARGET=arm64-apple-macos11 FFMPEG_VARIANT=folia ./build-macos.sh

Outputs are written below artifacts/. Source downloads use HTTPS and are rejected unless they match the pinned SHA-256 in common.sh.

Verify

For a native Linux build, pass the Folia binary and an optional full reference FFmpeg used only to generate synthetic E-AC-3-in-M4A and CAF fixtures:

./verify-folia.sh artifacts/ffmpeg-8.1.2-folia-x86_64-linux-gnu/bin/ffmpeg /usr/bin/ffmpeg

Verification checks the component allowlist, absence of network protocols, FLAC/WAV output, complete decoding through the null muxer, 96 kHz preservation, synthetic DSF and DSDIFF input brought down to 88.2 kHz, E-AC-3 in .m4a, and CAF input.

Windows ARM64 cross-compiles on Linux with a checksum-pinned LLVM-MinGW toolchain. CI checks the PE machine type and rejects toolchain DLL dependencies, then runs verify-folia.sh on windows-11-arm before publishing a release. The ARM64 archive is named ffmpeg-8.1.2-folia-aarch64-w64-mingw32.tar.gz; it contains the same source and license metadata as the other targets.

Releases

Tags such as v8.1.2-folia.1 build every supported target and publish:

• one target-specific .tar.gz per platform and architecture;
• the exact corresponding FFmpeg source archive;
• SHA256SUMS covering every published archive.

Each binary archive also contains share/folia-ffmpeg/BUILD-INFO.txt, the FFmpeg LGPL text, and the build-scripts MIT license.

Folia's application repository should pin a release asset and SHA-256 in its own manifest, download it during packaging, and copy only bin/ffmpeg (or bin/ffmpeg.exe) into resources/ffmpeg/.

Upstream variants

The original decode and encode variants remain available for upstream comparison. Folia releases build only the folia variant.