building ffmpeg for opencv - Specific case Ubuntu 16.04

ffmpeg-build.txt

# Similar ffmpeg issue https://github.com/opencv/opencv/issues/9794
# Generic Build: https://trac.ffmpeg.org/wiki/CompilationGuide/Generic
# Issues resolved:
# https://github.com/Homebrew/legacy-homebrew/issues/17004
# https://superuser.com/questions/1022116/ffmpeg-build-with-v4l2

cd ~/ffmpeg_source
./configure --enable-indev=v4l2 --enable-avresample
make all -j
sudo make install
sudo ldconfig

# https://launchpad.net/~libv4l/+archive/ubuntu/stable
sudo add-apt-repository ppa:libv4l/stable
sudo apt-get update
sudo apt install -y v4l-utils
# -DWITH_V4L