goldendict-ng/website/docs/howto/how to build ffmpeg for visual studio.md

# use vcpkg to build the ffmpeg.

Steps:

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

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

**cons**: seems lack libspeex or I just download the wrong package.

**pros**: easy to manage.


# I have tried the following methods with no luck

##  use the scripts provided by the following url

https://github.com/Microsoft/FFmpegInterop/issues/67

https://github.com/Microsoft/FFmpegInterop   


did not know how to link with libspeex. 

##  conan
  
  conan seems has not included libspeex option up to now.


# links worth checking
https://stackoverflow.com/a/44556505/968188