[FFmpeg-devel] Compatibility of different library versions (was: avformat: Add internal flags for AV(In|Out)putFormat)

[Nicolas George]

James Almer (12021-06-16):
> Considering this discussion started about lavd and lavf, and at no point in
> your email you said "all libraries" when suggesting version locking anything
> (In fact, you mistakenly wrote "only versions from the same version"), i
> figured it would be obvious i was commenting specifically about lavd<->lavf.

Ok, I read too much in your wording after you read too little in mine.
No problem.

> Of course i am against doing so for all libraries. They are already locked
> at the major soname level as required, and that's enough.
> Lavd as is is locking certain lavf's public structs and making it impossible
> to add new fields to them, which constricts development considerably, so
> making their locking strict to at least the minor soname level is a very
> good idea. But this isn't an issue at all for other libraries.
> I can add new fields to any public lavc struct, compile it and have a lavf
> that was linked to an old lavc use it at runtime, and it will work just
> fine.
> I see no benefit to your suggestion that's worth removing such freedom from
> the end user.

I am sorry, but you are not looking hard enough. You are describing ONE
of the several compatibility issue we have, the one that happens most on
lavf-lavd.

But please realize that every single avpriv symbol is a reason to lock
all libraries version of its own.

It is very dense for lavd, but lavd is tiny. There are tons of it on the
lavc-lavc side, many different from each other and requiring subtly
different solutions if they need updating.

Furthermore, what you explained is not a reason to be against, it is the
absence of reason to be for. Opposing something is not the same thing as
not supporting it: if you do not care, or if you do not know, you are
encouraged to neither oppose nor support.

So, I ask again:

Do you have a reason to oppose locking all library versions together?

Regards,

-- 
  Nicolas George
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