[MacPorts] #50697: VLC @2.2.2: build fails when using recently released ffmpeg-3.0

[MacPorts]

#50697: VLC @2.2.2: build fails when using recently released ffmpeg-3.0
----------------------------+-------------------------
  Reporter:  devans@…       |      Owner:  rjvbertin@…
      Type:  defect         |     Status:  new
  Priority:  Normal         |  Milestone:
 Component:  ports          |    Version:
Resolution:                 |   Keywords:
      Port:  VLC VLC-devel  |
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Comment (by devans@…):

 Replying to [comment:23 rjvbertin@…]:
 > Replying to [comment:21 devans@…]:
 >
 > > You should remove the following dependencies:
 > > {{{
 > >                     port:libvorbis \
 > >                     port:libopus \
 > >                     port:libogg \
 > >                     port:libtheora \
 > >                     port:libass \
 > >
 > > }}}
 >
 > I left those in because I saw the corresponding entries show up in the
 list of supported codecs and containers that is printed after the
 configure step, and I don't know exactly for what VLC uses ffmpeg.
 None of them are enabled in your configuration so won't be used by ffmpeg.
 Looking at the VLC code, it has its own modules for these
 under modules/codec.  VLC uses ffmpeg in modules/codec/avcodec for support
 of basic mpeg audio and video streams. VLC may need these dependencies but
 not via ffmpeg. See

 {{{
 modules/codec/ogg.c
 modules/codec/opus.c
 modules/codec/vorbis.c
 modules/codec/theora.c
 ...
 }}}

 >
 >
 > > Most of these are supported directly by VLC without using ffmpeg
 >
 > Including x264 (H.264 compression) and XviD, or anything text related
 that could benefit from freetype/fontconfig?
 Yes, for instance
 {{{
 modules/codecmodules/codec/x264.c
 }}}

 In ffmpeg, freetype/fontconfig are only used (if enabled) in the drawtext
 filter which draws text on video frames. VLC doesn't use ffmpeg filters or
 libavfilter (not enabled in ffmpeg contrib build).

 >
 >
 > > To avoid any linking issues/conflicts I would do as VLC does in the
 contrib build and build static libraries only.
 > > {{{
 > > --disable-shared --enable-static
 > > }}}
 > >
 >
 > I'd like to try to use shared libraries, to give the subport the maximum
 raison d'être. There are 4 or 5 modules that link to ffmpeg libraries.
 >
 > Anyway, I'll try, but I'm not convinced that it'll help:
 >
 > > Did you try appending -L${prefix}/lib/vlc/ffmpeg/lib to LDFLAGS?
 >
 > No, because that argument is already added where required (I checked,
 but otherwise the link would simply fail). I think the issue is that there
 is also a -L${prefix}/lib argument which cannot be omitted. It's not the
 first time I'm dealing with this kind of issue (for libraries or headers).
 What I should check is the possibility of editing the .pc file so that it
 outputs the absolute paths to the library binaries rather than using -Lfoo
 -lbar.

 You might look at how the ffmpeg contrib build does this.  They fix up the
 .pc files as part of this build.
 >

-- 
Ticket URL: <https://trac.macports.org/ticket/50697#comment:24>
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