[Libav-user] compiling ffmpeg with -fPIC

Zanelli Franco fzanelli at tecnosens.it
Mon Oct 28 17:14:04 CET 2013

Il 28/10/2013 16:58, Alex Cohn ha scritto:

	On Oct 28, 2013 3:21 PM, "Zanelli Franco" <fzanelli at tecnosens.it> wrote:
	> Ok,
	> I'd like to make a shared library called mylib.so that include static ffmpeg libraries libavcodec.a libavformat.a ..etc. in order to have just one shared library
	> I'm working on a linux machine 64 bit (ubuntu 12.04).
	> I've built ffmpeg libraries from ffmpeg 2.0.1 sources with this configuration:
	> --prefix="$HOME/ffmpeg_build"   --extra-cflags="-m64 -I$HOME/ffmpeg_build/include" --extra-ldflags="-L$HOME/ffmpeg_build/lib"   --bindir="$HOME/bin" --extra-libs="-ldl" --enable-gpl --enable-libmp3lame --enable-libx264 --enable-pic

	Have you tried
	... --extra-cflags="-fPIC -m64 -I$HOME/ffmpeg_build/include"

Yes I did. I got the same response that using --enable-pic.
I tried also to use -mcmodel=large, but in that case ffmpeg compilation didn't success

	> When I link the avlibs in mine, with this command:
	> gcc -m64    -o mylib.so  -L../ffmpeg_build/lib /home/uts/ffmpeg_build/lib/libavcodec.a -Wl,-R. -shared -s -fPIC
	> I always get this error:
	> /usr/bin/ld: /home/uts/ffmpeg_build/lib/libavcodec.a(deinterlace.o): relocation R_X86_64_PC32 against symbol `ff_pw_4' can not be used when making a shared object; recompile with -fPIC
	> /usr/bin/ld: final link failed: Bad value
	> The same procedure on a x86 linux platform succeded.
	> This is the same problem experienced from Dayana in this mailing list the 1st may 2013, I read the answers but they were not helpful
	> Can you help me please?
	> thank you

	Alex Cohn

	Libav-user mailing list
	Libav-user at ffmpeg.org



Ing. Franco Zanelli
Sviluppo Software - Divisione Sistemi Videosorveglianza 
Software Engineer - Videosecurity System Division 

Via Vergnano, n.16, 25125 BRESCIA - ITALIA
Tel: +39 030.3534144 Fax: +39 030.3530815
Email: fzanelli at tecnosens.it
Web: http://www.tecnosens.it <http://www.tecnosens.it/>  

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