Just a follow up if someone finds this thread with the same problem:
You have to put the includes into an extern "C" section like:
extern "C" {
#include
#include
#include
#include
}
Haven't a case where I needed extern "C" for includes as most libraries
seem to put headers that need to be handled with classic C ABI inside
those sections so it took some time to find this problem.
Regards,
Ingmar
On 23.02.2018 09:03, Ingmar Rieger wrote:
Hello,
I'm building a small tool to run on a Raspberry Pi while I shoot
timelapses where I transfer the small JPG files shot besides my raw
files and use them for exposure checking and correction. As I already
have them on the raspi then I'd like to write a small preview movie clip
from them. Therefore I'd like to use libav/ffmpeg with the omx plugin
for hardware encoding giving it the images directly from ram as I
already have those JPG files open for exposure analyzing.
To start playing with libav I just build a small app opening a bunch of
jpg files one after another and wanted to add libav encoding. For
starters I copied the encode function from the "encode_video.c" example
and tried to compile to check if includes and linking are working and
always end up not being able to link.
My example file (main.cpp), the CMakeLists.txt for building it and my
compiler output is here:
https://gist.github.com/irieger/f044f7920aec0b92dad29827b6fe7e79
(My files are in /home/pi/dev/test/ffmpeg-encode (build in separate
directort /home/pi/dev/test/ffmpeg-encode/build) and ffmpeg is compiled
and installed from source with omx support with
PREFIX=/home/pi/bin/ffmpeg [./configure --prefix=/home/pi/bin/ffmpeg
--enable-mmal --enable-omx --enable-omx-rpi --enable-shared --enable-pic])
I searched for a while but I can't find a clue what's going wrong here.
Can anyone here hel me with this? Why will linking fail in this case?
Same result with `g++ -std=c++11 -Wall -I /home/pi/bin/ffmpeg/include -o
encode-test main.cpp -lOpenImageIO -L/home/pi/bin/ffmpeg/lib -lavformat
-lavcodec -lavutil -lswresample -lswscale`
--
Kind regards,
Ingmar
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