tce-load -i compiletc python3.8-meson gst-plugins-base-dev ffmpeg-dev

wget https://gstreamer.freedesktop.org/src/gst-libav/gst-libav-1.16.2.tar.xz

cd gst-libav-1.16.2

mkdir build
cd build

CC="gcc -march=armv8-a+crc -mtune=cortex-a72 -Os -pipe" CXX="g++ -march=armv8-a+crc -mtune=cortex-a72 -Os -pipe -fno-exceptions -fno-rtti" meson --prefix=/usr/local --localstatedir=/var --libexecdir=/usr/local/lib --buildtype=plain ../

[-fno-exceptions -fno-rtti fails]

ninja [0m 7.85s]
sudo ninja install