If you have downloaded the source code, you can view it in ffmpeg-4.3.1/doc/examples/
On Ubuntu 16.04, after installing ffmpeg through the source code, run the official example
gcc -o demux demuxing_decoding.c -I /usr/local/include/ -L /usr/local/lib -lavcodec -lavformat -lavutil
As the installation configure path is / usr / local, header files will be installed in / usr / local / include, which is the default linux the header file search path, so -I /usr/local/include/do not need.
gcc -o demux demuxing_decoding.c -L /usr/local/lib -lavcodec -lavformat -lavutil
However, if you do not specify the dynamic library loading path -L /usr/local/lib, the path of -lavcodec will default to /usr/lib/x86_64-linux-gnu/libavcodec-ffmpeg.so.56, but the correct path should be /usr/local/lib/libavcodec. so.58. This is because before according to the official guide to install OpenCV, using apt required to install the appropriate libavcodec library ...
[required] sudo apt-get install cmake git libgtk2.0-dev pkg-config libavcodec-dev libavformat-dev libswscale-dev
When gcc compiles the program, the sequence of finding the so dynamic library is as follows:
-
The path specified by the parameter -L when gcc is compiled
-
Environment variable LIBRARY_PATH
-
System default library location /lib, /usr/lib
Configure environment variables in the ~/.bashrc file
# 编译时链接动态库路径
export LIBRARY_PATH=/usr/local/lib/:$LIBRARY_PATH
# 运行时链接动态库路径
export LD_LIBRARY_PATH=/usr/local/lib/:$LD_LIBRARY_PATH
Make the ~/.bashrc file effective again
source ~/.bashrc
So just need
gcc -o demux demuxing_decoding.c -lavcodec -lavformat -lavutil