[FFmpeg-user] Building ffmpeg with libvpx (custom installation prefix)

[Moritz Barsnick]

Hi Jonathan,

On Tue, Jun 02, 2015 at 14:25:53 -0400, Jonathan Bouchard wrote:
>    1. I built libvpx v1.4.0 from git, using "./configure
>    --prefix=/path/to/libvpx && make install -j16"

"--prefix" is the path where ffmpeg will be installed, not where it
finds dependencies.

> It seems that ffmpeg configure script tries to determine libvpx version by
> compiling a small C program. However, the gcc invocation doesn't include
> the cflag "-I/path/to/libvpx/include". Which results in an error:
> "/usr/tmp/ffconf.F6UtZ8Vr.c:1:29: error: vpx/vpx_decoder.h: No such file or
> directory" (line 9482 of the log).
> 
> Note: I invoked "pkg-config --cflags vpx" on my machine and it properly
> returns "-I/path/to/libvpx/include"

ffmpeg's configure script doesn't seem to use pkg-config for libvpx.
(For whatever reason. Turn to the ffmpeg-devel list for such question.
I had wondered about the same pkg-config support for libx264 here, got
some answer ["avoiding it... what doesn't work for you"], but it was
eventually introduced some months later, because it was apparently
useful after all.)

So you will have to provide those paths yourself:

I usually do something like:
  --extra-cflags="-I/path/to/libvpx/include" --extra-ldflags="-L/path/to/libvpx/lib"

but the proper way in your pkg-config case is probably:
  --extra-cflags="`pkg-config --cflags vpx`" --extra-ldflags="`pkg-config --libs vpx`"
(or "pkg-config --libs-only-L vpx")

Hope this works,
Moritz