FFmpeg
XPression INcoder and XPression Video Coder make use of FFmpeg licensed under the LGPLv2.1 and its source can be downloaded here.
FFmpeg was configured with the following options:
---pkg-config=pkg-config --pkg-config-flags=static --extra-version=ffmpeg-windows-build-helpers
--disable-debug --disable-w32threads --arch=x86 --target-os=mingw32 --cross-prefix=/root/src/sandbox/cross_compilers/mingw-w64-i686/bin/i686-w64-mingw32
--enable-gray --enable-libopus --enable-libsnappy --enable-libsoxr --enable-libtheora
--enable-libvorbis --enable-libwebp --enable-libzimg --enable-libopenjpeg
--enable-libopenh264 --enable-libxml2 --enable-libdav1d --enable-cuda-llvm
--enable-libvpx --enable-nvenc --enable-nvdec --extra-libs=-lm --extra-libs=-lpthread
--extra-cflags=-DLIBTWOLAME_STATIC --extra-cflags=-DMODPLUG_STATIC --extra-cflags=-DCACA_STATIC
--disable-amf --enable-libmfx --enable-avresample --extra-cflags='-mtune=generic'
--extra-cflags=-O3 --enable-shared --disable-static --prefix=/root/src/sandbox/win32/ffmpeg_git_lgpl_n4.3.2_shared
A patch of changes to FFMPEG 4.3.2 is available in the downloaded source as xpvc_win.patch.