Normalize video audio level

ffmpeg -i test.mkv -vn -af "volumedetect" -f null /dev/null 
# ...
# [Parsed_volumedetect_0 @ 0x55d5e9291a80] mean_volume: -54.6 dB
# ...
ffmpeg -i test.mkv -vcodec copy -af "volume=24dB" test_boosted.mkv