vendoring and precompilation

[kevinschweikert]

Hey, just wanted to ask you, if in the context of elixir-nx/bumblebee#403 it would make sense to vendor the libs and support precompilation as mentionen by the bumblebee maintainers.
Would you be open to it?

[mickel8]

Hi, I tried providing ffmpeg as precompiled dependency but it wasn't too easy. Anyway, I am open for suggestions :)

[kevinschweikert]

I'm absolutely no expert in this matter but wouldn't it be enough to add ffmpeg dev dependencies in CI and add configure elixir_make like in this Precompilation Guide? Or am i missing something?

[mickel8]

But this only instructs how to create a precompiled version of OUR NIF, correct? And what we need to do at first is to make Xav download precompiled version of FFmpeg instead of using the one installed on your OS. If we have the latter one, we can think about precompiling Xav itself. Does it make sesne?

[mickel8]

Hi @kevinschweikert, any ideas what to do with this one 😅

[kevinschweikert]

Okay, here are my thoughts. Currently, we dynamically link iibav packages and expect them to be available on the system which runs xav. We could either precompile the NIF with statically linked libraries for each of the operating systems/architectures. That should(?) be possible with CI.
The other thing I was thinking about using the zig build chain, to cross compile from a single host system. This would make CI much simpler. We wouldn't have to write Zig code because zig can compile C/C++ code natively.
I was looking at https://github.com/allyourcodebase/ffmpeg where they compile ffmpeg with zig. The https://github.com/burrito-elixir/burrito project also uses zig to compile an Elixir application to a cross-platform executable.
I would need some time, to figure out, how all this works and if the zig way is a good way but would be happy to work on it, when you think, that this could be a benefit for xav

[kevinschweikert]

Hey @mickel8 i'm slooooowly wrapping my head around this! The missing piece for me was that libavcodec for example is also already a precompiled artifact and not the source code itself. Somehow i missed that in my understanding. That's why you said, that we would have to precompile ffmpeg ourselves! I watched some talks about zigler and with E-xyza/zigler#479 it could be a great solution. I will investigate more about compiling libav/ffmpeg with zig and zigler