[FFmpeg-cvslog] r21731 - in branches/0.5: . Changelog doc/APIchanges libavcodec/avcodec.h libavcodec/utils.c

[Uoti Urpala]

On Wed, 2010-02-10 at 11:00 +0100, Reinhard Tartler wrote:
> On Di, Feb 09, 2010 at 22:28:09 (CET), Ramiro Polla wrote:
> > -#define LIBAVCODEC_VERSION_MINOR 20
> > +#define LIBAVCODEC_VERSION_MINOR 21

> > This is bad.
> 
> why?
> 
> > We have the same version bump for 2 different things. How should we
> > deal with library versions in the branches?
> 
> We don't. Let me explain:
> 
> since nothing in the ffmepg source checks for LIBAVCODEC_VERSION_MINOR,
> this has can have only effect on other applications that link
> dynamically against avcodec.

You need to consider more than binary compatibility. The minor version
bumps typically add new public functions or definitions; the original
minor 21 added av_parser_parse2 for example. A user application that
wants to support older libavcodec versions could have code like this:

#if LIBAVCODEC_VERSION_MINOR >= 21
av_parser_parse2(...)
#else
...
#endif

Compiling this application against the release branch would fail now, as
it'd try to use a function not present in the old release code.