Christopher Sawtell wrote:
On Tuesday 24 February 2009 12:37:45 Stephen Irons wrote:
> I have installed ffmpeg from the Ubuntu repositories.
man gcc
pay particular attention to the -L option flag.
and then if you are an obedient purist, alter the necessary
configuration files, generate a new .deb file and install form that.
Being an obedient purist is seriously recommended.
--
With Sincerity,
Christopher Sawtell
-L/usr/local/bin as an option to gcc did not change anything. I think
that option only affects static linking -- it tells the linker where to
look for libraries. Or perhaps where to find the stubs necessary to link
a library dynamically. But it did not affect the loading at run-time.
But I found two solutions:
1. ./configure --extra-ldflags=-Wl,-rpath/usr/local/bin stores that path
in the executable to tell the program loader to also search
/usr/local/bin for libraries.
2. ./configure --build-suffix=-ZZZ changes the names of the libraries to
lib-avcodec-ZZZ.so.66.whatever. These names are stored in the
executable, so they are found correctly.
man ld gives the full search order for *linking*:
* -rpath-link options
* -rpath options
* LD_RUN_PATH environment variable
* On *SunOS*, directories specified using -L -- this is what
Christopher Sawtell suggested, but does not work on Linux
* LD_LIBRARY_PATH
* DT_RUNPATH or DT_RPATH
* default directories /lib and /usr/lib
* directories in /etc/ld.so.conf
man ld.so gives a different order for *loading*:
* LD_LIBRARY_PATH
* From the cache file /etc/ld.so.cache, created by ldconfig
* /lib and /usr/lib
But this does not describe what I actually saw happening, so I prefer
the search order given in man ld. I think that the *linker* was finding
the necessary library stubs in /usr/lib, so it never bothered to look in
/usr/local/lib.
Anyway, my version of ffmpeg with AMR support is now working...so I can
once again convert videos from my phone to ... whatever ... they are
still rubbish.
I should probably make a .deb package so that I can install into
/usr/bin and /usr/lib so that other applications get the newer version
of ffmpeg and libav* ... but what will it break? Nothing, provided that
the library authors have got their version numbering correct.
Stephen Irons
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