Compilation FFmpeg fails

[John Rose]

Tried to compile FFmpeg (on Ubuntu 18.04) using instructions at: ​https://trac.ffmpeg.org/wiki/CompilationGuide/Ubuntu

Source was obtained from link ​https://johnvansickle.com/ffmpeg/builds/ffmpeg-git-amd64-static.tar.xz

All well until "ERROR: gnutls not found using pkg-config".

Terminal output attached.

[John Rose]

Terminal output

[Carl Eugen Hoyos]

Please ask all usage questions on the user mailing list but please understand that we do not support third-party scripts.

[John Rose]

This script (i.e. procedure) was the one on trac.ffmpeg.org website (i.e. this one):

​https://trac.ffmpeg.org/wiki/CompilationGuide/Ubuntu

[John Rose]

This script (i.e. procedure) was the one on trac.ffmpeg.org website (i.e. this one):

​https://trac.ffmpeg.org/wiki/CompilationGuide/Ubuntu

[Artem]

While that looks like 3rd party software issue at a glance it does not seem so after closer check.
It looks like something with configure script. Please check attachment ffmpeg_configure_output.txt​ which shows the actual configure error.
Just to be clear gnutls is installed and pkg-config test passes but script fails on later stages (check_func_headers).
You could also check a simple docker file (attached) which reproduces the issue. That is just "compilation" of commands presented on "compilation guide" page.

[Artem]

Simple docker file compiled from ffmpeg manual to reproduce an issue

[danadam]

In my case (Debian Testing) I have:

/usr/bin/ld: cannot find -lunistring
collect2: error: ld returned 1 exit status
ERROR: gnutls not found using pkg-config

In gnutls.pc there is:

Libs: -L${libdir} -lgnutls
Libs.private:    -pthread   -lgmp -lunistring -latomic

The --pkg-config-flags="--static" option to configure makes it use "Libs.private" line, so it tries to link with unistring. The problem is that "libgnutls28-dev" does not depend on "libunistring-dev".

I removed the option and it fixed the issue. I suspect that manually installing "libunistring-dev" would also fix it, although I found this regarding static linking of gnutls: ​https://gitlab.com/gnutls/gnutls/-/issues/203

Nikos Mavrogiannopoulos @nmav · 3 years ago

Note that static linking applications with gnutls is not something supported. gnutls relies on library constructors and destructors which are not loaded when linking statically.