[gstreamer-bugs] [Bug 584399] New: FFmpeg libraries are included in incorrect order when external FFmpeg is used

[GStreamer (bugzilla.gnome.org) <bug...@bu...>]

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  GStreamer | gst-ffmpeg | Ver: git
           Summary: FFmpeg libraries are included in incorrect order when
                    external FFmpeg is used
           Product: GStreamer
           Version: git
          Platform: Other
        OS/Version: Windows
            Status: UNCONFIRMED
          Severity: trivial
          Priority: Normal
         Component: gst-ffmpeg
        AssignedTo: gst...@li...
        ReportedBy: lr...@gm...
         QAContact: gst...@li...
     GNOME version: Unspecified
   GNOME milestone: Unspecified


When external FFmpeg is used, configure.ac does:

  PKG_CHECK_MODULES(FFMPEG, libavutil libavcodec libavformat)
  PKG_CHECK_MODULES(POSTPROC, libavutil libavcodec libpostproc)
  PKG_CHECK_MODULES(SWSCALE, libavutil libswscale)

which implicitly adds proper libraries to the list of linker's arguments.
But when internal FFmpeg is used, all library dependences are specified
explicitly:

  FFMPEG_LIBS="\$(top_builddir)/gst-libs/ext/ffmpeg/libavformat/libavformat.a \
               \$(top_builddir)/gst-libs/ext/ffmpeg/libavcodec/libavcodec.a \
               \$(top_builddir)/gst-libs/ext/ffmpeg/libavutil/libavutil.a"

  POSTPROC_LIBS="\$(top_builddir)/gst-libs/ext/ffmpeg/libpostproc/libpostproc.a
\
                 \$(top_builddir)/gst-libs/ext/ffmpeg/libavutil/libavutil.a"

  SWSCALE_LIBS="\$(top_builddir)/gst-libs/ext/ffmpeg/libswscale/libswscale.a \
                \$(top_builddir)/gst-libs/ext/ffmpeg/libavutil/libavutil.a"

The order (format->codec->util in the latter and util->codec->format in the
former) is different and the difference causes gst-ffmpeg to spew link-time
errors ("undefined reference to ...") when linking against external FFmpeg.


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