[FFmpeg-devel] Re: [RFC] C++

["Tomas Härdin via ffmpeg-devel" <ffmpeg-devel@ffmpeg.org>]

ons 2025-10-22 klockan 14:09 +0200 skrev Gregor Riepl via ffmpeg-devel:
> > My main motivation is to be able to use STL, which would simplify
> > string handling and memory management, and give us access to its
> > data
> > structures. Manual memory management has its place, especially in
> > lavc.
> > In lavf less so. RAII would do wonders in de-gotofying error
> > handling.
> > Features like std::filesystem, std::chrono, std::thread etc
> > abstract
> > away many OS particularities. Thorough STL-ification would render
> > parts
> > of lavu obsolete. avstring.*, bprintf.* and tree.* come to mind.
> > This
> > would have security benefits. Another reason is stronger typing,
> > which
> > tends to reveal bugs.
> 
> Just for the sake of the argument: Wouldn't it be better to opt for
> an even safer language than C++, like Rust?

There was a discussion about Rust a while back. I'm not really against
it, but the impedance mismatch is much greater. Plus there's the need
for an entirely different set of compilers. Most of our users know C++
already.

That said, gccrs is making progress so perhaps at some point this might
happen. C++ is still an improvement over the present state of things.
Plus, Katamari-C++ is likely to grow the same kind of features Rust has
anyway.

I've continued to hack at mxfdec.cpp and I'm now seeing substantial
performance improvements thanks to using STL. 182% faster
mxf_read_header for a 10,000 second file generated by mxfenc.c. This is
likely to shoot up even more as I rework the MXFIndexTableSegment code.
Greater still would be the effect of lazy reading of partitions, which
is my overall goal. I'll probably push something to forgejo once it's
firmed up a bit. Especially for Baptiste to take a look at.

I feel I should reiterate the point that whatever we choose to do we
should keep the C API, because C's ABI is stable. C++'s isn't, and
based on what Rémi is saying Rust's isn't either.

/Tomas
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