linking order matters definitely! see this nice introductory post
http://eli.thegreenplace.net/2013/07/09/library-order-in-static-linking/
put -lx264 after -lavcodec!
Peter
On 08/30/2016 01:28 PM, Javier Lopez wrote:
I simplified a few using the pkg-config to one call by using both flags:
--clibs and --cflags:
gcc -o ffmpeg_player ffmpeg_player_01.c -Wall -ggdb $(pkg-config --cflags
--libs libavformat libavcodec libswresample libswscale libavutil sdl) -lm
And it worked!
I also tried to compile without the pkg-config adding all dependencies:
gcc -o ffmpeg_player ffmpeg_player_01.c -Wall -ggdb -lavformat -lvdpau
-lva -lva-drm -lva-x11 -lxcb -lxcb-shm -lxcb -lxcb-xfixes -lxcb-render
-lxcb-shape -lX11 -lasound -lSDL -lx264 -lmp3lame -lfdk-aac -lm -lz
-pthread -lavcodec -lvdpau -lswresample -lswscale -lavutil -lSDL
Still I have following error: libavcodec/libx264.c:814: undefined reference
to `x264_encoder_open_148'
I listed all dependencies of libavcodec and all of them where included,
perhaps order minds.
2016-08-29 16:11 GMT+02:00 Javier Lopez <[email protected]>:
I would like to simplify in order to add more libs to the ffmpeg like
opencl and sdl libs and I do not know how to link using pkg-config
combined with no pkg-config libraries
I tried to add the sdl-config but it did not worked.
I will try to add all those libraries and to list them using pkg-config
--libs,
javier
2016-08-29 14:29 GMT+02:00 Perette Barella <[email protected]>:
Then I can compile and link using the following command line:
gcc -o ffmpeg_grabber ffmpeg_grabber_03.c -Wall -ggdb $(pkg-config
--cflags libavformat libavcodec libswresample libswscale libavutil sdl)
$(pkg-config --libs libavformat libavcodec libswresample libswscale
libavutil sdl) -lm
But I have a lot of link errors (undefined a lot of things) removing
pkg-config:
gcc -o test test.c -Wall -lavformat -lavcodec -lswresample -lswscale
-lavutil -lm
The question is: How to avoid undefine errors without using the
pkg-config?
When static linking, you need to link not only the ffmpeg libraries
themselves, but all the libraries that they link to in turn. In this
command:
pkg-config --libs libavformat libavcodec libswresample libswscale
libavutil sdl
`pkg-config --libs` gets the link flags necessary (there’s also a
--cflags option too), including all those indirectly needed libraries, to
link. You can run pkg-config --libs on the command line to see the list.
This list will not always be the same. My Mac, for example, includes
pthreads among the automatically-linked system libraries, so there will be
no ‘-lpthreads’, but it includes -L/opt/local/lib, because it’s installed
in a non-default place where the linker won’t look. Link flags also depend
on what ffmpeg was configured and built with: for example, if libfoobar is
installed, there could be a dependency for -lfoobar; but if missing when I
ran ./configure on ffmpeg, then I might have ffmpeg but without whatever
capabilities foobar provides. `configure` scripts see what’s available and
build what they can, and they often utilize information from pkg-config
where it’s available.
I wonder *why* are you avoiding pkg-config? Are you planning to
build/compile on a system without it? Are you thinking of a portable
`configure` script, and considering what to do if pkg-config is missing?
Because pkg-config came about to solve the problem you’re running into.
I’ve seen some debate about whether pkg-config solves the problem right,
but it is the thing in place and trying to avoid it is to make yourself
problems. Not using it means a lot of extra trouble, so unless you have a
*really* good reason...
Perette
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