[digiKam-users] bootstrap can't find ffmpeg

[Martin Burnicki]

Hi,

Andrey Goreev wrote:
> Hello,
> 
> 
> I am trying to compile digikam-git on ubuntu 18.04 but keep getting this
> error message:
> 
> -- FFMPEG_FOUND = FALSE
> -- FFMPEG_INCLUDE_DIRS = /usr/include/x86_64-linux-gnu
> -- FFMPEG_LIBRARIES =
> /usr/lib/x86_64-linux-gnu/libavcodec.so;/usr/lib/x86_64-linux-gnu/libavformat.so;/usr/lib/x86_64-linux-gnu/libavutil.so;/usr/lib/x86_64-linux-gnu/libswscale.so
> -- FFMPEG_DEFINITIONS =
> 
> I compiled ffmpeg myself but bootstrap did not find it.
> 
> Then I installed ffmpeg from ubuntu repos but bootstrap can't seem to
> locate it either.
> 
> 
> I checked and the files
> 
> /usr/lib/x86_64-linux-gnu/libavcodec.so;
[...]

If you *run* a program then it's sufficient if the .so files are
available. However, if you *build* a program then the associated header
files need to be available so that the compiler knows which function a
.so file provides, and how to call those functions.

I don't run Ubuntu here, but if you install an ffmpeg package from a
repo then there should be an associated ffmpeg-devel (or similar)
package which provides the header files required to build a program with
ffmpeg support. Same for other libraries that you need to build a program.

As Gilles has already mentioned, many build scripts use the pkg-config
tool to provide information about an installed package. However, if you
build ffmpeg yourself without setting up a package first then the
information for pkg-tool may not be available, so depending on how the
build script is supposed to work, it *might* be unable to detect the
header files and library when you try to build DK, just because pkg-tool
doesn't have the associated information.

Just my thoughts. ;-)

Martin