Compiling FFmpeg - Windows.txt

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Compiling FFmpeg On Windows ************
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0. Helpfull Resources ******************

https://cygwin.com/install.html
https://superuser.com/questions/1425350/how-to-compile-the-best-version-of-ffmpeg-for-cygwin-windows

https://winlibs.com/
https://github.com/TechSmith/FFmpeg/tree/main/Windows

Since we want to build FFmpeg ourself to configure it to our liking, we need unix building tools like 
gcc (compiler) and make. There is several ways to get these, i chose cygwin.


1. Cygwin 

This worked well for me. See:
https://superuser.com/questions/1425350/how-to-compile-the-best-version-of-ffmpeg-for-cygwin-windows

1.1. Install cygwin and basic tools

Install https://cygwin.com/install.html
- option "download from internet"
- install to C:\cygwin64
- for All users
- use system proxy settings
- select mirror
Then install:
- from category "Net": wget
- from "Base": tar and gawk
- from "Devel": git
- from "Libs": libiconv
DON'T INSTALL EVERYTHING! 


1.2. Install the apt-cyg package manager

mkdir -p /usr/local/src 
cd /usr/local/src
git clone https://github.com/kou1okada/apt-cyg.git
ln -s "$(realpath apt-cyg/apt-cyg)" /usr/local/bin/


1.3. Install build tools

apt-cyg install autoconf
apt-cyg install automake
apt-cyg install binutils 
apt-cyg install cmake
apt-cyg install doxygen
apt-cyg install git 
apt-cyg install libtool 
apt-cyg install make 
optional: 	mercurial 

apt-cyg install mingw64-x86_64-SDL2 
apt-cyg install mingw64-x86_64-binutils 
apt-cyg install mingw64-x86_64-gcc-core 
apt-cyg install mingw64-x86_64-gcc-g++ 
apt-cyg install mingw64-x86_64-headers 
apt-cyg install mingw64-x86_64-libvpx 
apt-cyg install mingw64-x86_64-runtime 
apt-cyg install mingw64-x86_64-win-iconv 
apt-cyg install mingw64-x86_64-windows-default-manifest 
apt-cyg install mingw64-x86_64-zlib 
optional: 	apt-cyg install mingw64-x86_64-libtheora 
optional: 	apt-cyg install mingw64-x86_64-fribidi 

apt-cyg install nasm 
apt-cyg install pkg-config 
apt-cyg install subversion 
apt-cyg install texinfo 
apt-cyg install yasm


1.4. compile FFmpeg

Download source code of ffmpeg (bzip2), if not in this project (/ffmpeg/ffmpeg-5.1.2.tar.bz2).
FFmpeg-Version: 5.1.2 "Riemann"
http://ffmpeg.org/download.html#get-sources

Goto cygwin console, then:

# extract source code
tar jxvf ffmpeg-5.1.2.tar.bz2

# go to unpacked directory
cd ffmpeg-5.1.2

# reset everything, when ever you want to reset your configuration, run this

make clean

# link/compile in libraries 
CFLAGS=-I/usr/x86_64-w64-mingw32/sys-root/mingw/include &&
LDFLAGS=-L/usr/x86_64-w64-mingw32/sys-root/mingw/lib &&
# pkg config
export PKG_CONFIG_PATH=  &&
export PKG_CONFIG_LIBDIR=/usr/x86_64-w64-mingw32/sys-root/mingw/lib/pkgconfig 

# configure, this is the most important part. FFmpeg should be configured
# with the following features:
# - output shared libraries
# - FFmpeg is LGPLv3 compliant
# - only file protocol
# - no programs, no documentation, no filters, no static builds
# - if possible don't use third libraries
#
# Run one of the following commands:
#
#### "normal" configuration: all decoders, all demuxers, all parsers ####
# prefix is where everything gets installed
make clean && \
./configure \
--prefix='../../win' \
--arch=x86_64 \
--target-os=mingw32 \
--cross-prefix=x86_64-w64-mingw32- \
--enable-cross-compile \
--pkg-config=pkg-config \
--pkg-config-flags=--static \
--extra-cflags=-static \
--extra-ldflags=-static \
--enable-shared \
--enable-static \
--enable-version3 \
--enable-avdevice \
--enable-avcodec \
--enable-avformat \
--enable-swresample \
--enable-swscale \
--enable-avfilter \
--disable-filters \
--disable-programs \
--disable-doc \
--disable-htmlpages \
--disable-txtpages \
--disable-manpages \
--disable-podpages \
--disable-libjack \
--disable-libopencore-amrnb \
--disable-libxcb \
--disable-libxcb-shm \
--disable-libxcb-xfixes \
--disable-indevs \
--disable-indev=jack \
--disable-outdev=xv \
--disable-securetransport \
--disable-protocols \
--enable-protocol='file' \


discarded options:
--enable-w32threads \
--extra-ldflags='-L/usr/local/x86_64-w64-mingw32/lib' \
--pkg-config=pkg-config \
--pkg-config-flags=--static \


This can take a while! Don't abort, That's actually a good sign!
Look for this in configure's output: "License: LGPL version 3 or later"
This means we are save.
If you see "License: nonfree and unredistributable" or something else, reconfigure

Then:
make -j$(nproc) &&
make install  


To check for dependencies in compiled dlls, try something like this in cygwin
ldd avcodec-59.dll
Apart from FFmpeg dlls there shouldn't be any other dependencies