Use vcpkg to build ffmpeg(on Windows).

Steps:

1. follow the instructions at https://trac.ffmpeg.org/wiki/CompilationGuide/vcpkg

2. run the command

   vcpkg.exe install ffmpeg[core,avcodec,avdevice,avfilter,avformat,speex,avresample,mp3lame,opus,sdl2,swresample,vorbis]:x64-windows-rel 
   

3. copy dll and libs in vcpkg\installed\x64-windows-rel to goldendict's winlibs\lib\msvc

Pros: Can be compiled with speex.

Alternative method

simply download ffmpeg from the official website: https://github.com/BtbN/FFmpeg-Builds/releases Then replace the dlls and libs in the winlibs\lib\msvc.

Cons: Seems to be missing libspeex or I just downloaded the wrong package.

Pros: Easy to manage.

conan

conan does not seem to have the libspeex option yet.

Links worth checking

https://stackoverflow.com/a/44556505/968188