Building Essentia's Python extension on Windows

Python.org Windows binaries are compiled against an MS Visual C++ (MSVC) runtime, which version differs with different Python versions. Essentia's Python extension should be built with MSVC too because the MinGW C++ library builds won't be compatible with MSVC.

In this guide we use VirtualBox Windows machine.

Preparing build environment

Download Dev Virtual Machine: https://developer.microsoft.com/en-us/windows/downloads/virtual-machines
Remove Visual Studio 2017 Community as we won't use it
Install Build Tools for Visual Studio 2017: https://www.visualstudio.com/downloads/#build-tools-for-visual-studio-2017
Make sure VC++ v140 toolset is installed: Visual Studio Build Tools 2017 preferences --> check "VC++ 2015.3 v140 toolset for desktop (x86,x64)"
Make sure Win10 SDK is also installed
Install Python 3, add path to python.exe to %PATH% variable
Patch distutils/msvc9compiler.py and distutils/msvccompiler.py (they are inside C:\Users\User\AppData\Local\Programs\Python\Python36-32\lib\distutils\ folder): add a line import setuptools
Force upgrade of the setuptools package: python -m pip install -U pip setuptools
Install pkg-config-lite (https://sourceforge.net/projects/pkgconfiglite/files/) to C:\workspace and add this path to %PATH% variable

Building dependencies

FFMPEG

There are FFmpeg builds available online (http://ffmpeg.zeranoe.com/builds/), but unfortunately those do not include libavresample. Therefore, we are building FFmpeg from scratch:

Install MSYS2: http://www.msys2.org/
Install Yasm: download the yasm-*.exe file, rename to yasm.exe and copy to C:\workspace
Install pre-requisites in MSYS2 terminal: pacman -S tar make gcc diffutils
Open "x86 Native Tools Command Prompt for VS 2017" and from this terminal open the Msys2 terminal (use the following flags to inherit %PATH% variable): C:\msys64\msys2_shell.cmd -msys -use-full-path
Go to the root Essentia folder (cd /c/ to access C:)
cd packaging/win32_3rdparty/
Build ffmpeg: ./build_ffmpeg_msvc.sh
Create *.lib export files

cd lib/
lib /def:avcodec-56.def /out:avcodec-56.lib
lib /def:avformat-56.def /out:avformat-56.lib
lib /def:avutil-54.def /out:avutil-54.lib
lib /def:avresample-2.def /out:avresample-2.lib
lib /def:swresample-1.def /out:swresample-1.lib

Rename:

avcodec-56.lib --> avcodec.lib
avformat-56.lib --> avcodec.lib
avutil-54.lib --> avutil.lib
avresample-2.lib --> avresample.lib
swresample-1.lib --> swresample.lib

FFTW

FFTW builds are available online: ftp://ftp.fftw.org/pub/fftw/fftw-3.3.3-dll32.zip (32-bit)

Generate .lib import file from .def file: http://www.fftw.org/install/windows.html
Keep the dll filename as it is, but rename the rest of files from libfft3f-3.* to fft3f.* to make waf find them (waf does not add "lib" prefix to the filenames)

Libsamplerate

We are providing prebuilt library files.

Rename files: libsamplerate-0.lib --> samplerate.lib

Taglib

Build from source:

Steps:

Install cmake: https://cmake.org/
cmake -DCMAKE_INSTALL_PREFIX=C:\users\User\Dev\lib
msbuild all_build.vcxproj /p:Configuration=Release
msbuild install.vcxproj
When build is done, copy files to packaging/win32_3rdparty (the dll file is in taglib/Release folder)
Patch taglib.pc