[FFmpeg-devel] [PATCH 5/7] avformat/mpegts: add s337m support

[Martin Storsjö]

On Tue, 10 Dec 2024, Scott Theisen wrote:

> ff_* symbols are not exported and are internal to each library. Some of 
> the other libraries `#include "libavutil/reverse.c"` in a file.  Should 
> ff_reverse be renamed avpriv_reverse so that is not necessary?

No, this is intentionally done this way.

If we'd make it into avpriv_reverse, then we'd also need to distinguish 
between whether we're accessing it from within the same library where it 
is defined, or mark the declaration with dllimport, if building shared 
libraries with MSVC.

Back when ffmpeg was made to support MSVC and building shared libraries 
with it, we decided not to try to add dllimport for it; these tables are 
miniscule anyway. So if building shared libraries, we instead duplicate 
the tables within each shared library that uses them.

(Later we did end up adding selective dllimport for cross-library tables 
anyway though. But we tend to prefer to avoid avpriv symbols if possible, 
as they're effectively part of the ABI surface even if they're supposed to 
be private.)

In any case - just replicate the existing pattern for duplicating 
reverse.c into libavformat, like is done in the other libraries that use 
the symbol; changing how it is set up is a much larger discussion.

// Martin