[packman] libffmpeg-devel

[Cristian Morales Vega]

2011/3/5 Manfred Tremmel <manfred at links2linux.de>:
> Hm, if x264 changes ffmpeg is rebuild, because ffmpeg itselve is build
> against x264. If ffmpeg is rebuild it triggers rebuilds of all packages
> which are build agains ffmpeg, didn't it? What rebuild can be saved if
> the libx264-devel dependency is removed? The trigger is only moved from
> libx264-devel to libffmpeg-devel, isn't it?

In some cases yes. But if the x264 change is minor* the ffmpeg build
will be exactly the same, build-compare will detect it, and packages
dependent of ffmpeg will not be rebuilt.

* With "minor" I mean anything that is not a soname change or an API
extension which is reflected in ffmpeg through macro voodoo. Anything
that will not create a different ffmpeg binary is "minor".


Looking at the last 11.4/x86-64 ffmpeg build I see

@@ -5535,8 +5535,8 @@
  415a80 2573220a 00736574 726c696d 69740041  %s"..setrlimit.A
  415a90 56436f64 6563436f 6e746578 74004156  VCodecContext.AV
  415aa0 466f726d 6174436f 6e746578 74006763  FormatContext.gc
- 415ab0 63003132 3a35373a 3136004d 61722020  c.12:57:16.Mar
- 415ac0 31203230 31310020 20627569 6c74206f  1 2011.  built o
+ 415ab0 63003039 3a35333a 3531004d 61722020  c.09:53:51.Mar
+ 415ac0 35203230 31310020 20627569 6c74206f  5 2011.  built o
  415ad0 6e202573 20257320 77697468 20257320  n %s %s with %s
  415ae0 25730a00 25732053 564e2d72 32303131  %s..%s SVN-r2011
  415af0 30323236 31343437 0a004400 20257325  02261447..D. %s%

so in the ffmpeg case every rebuild will be different since somewhere
there is a __DATE__ macro, but this can be fixed.