The following will get the YT livestream (it should be a .m3u8 file), and will output multiple %d.mp4
files, every 20 seconds thanks to ffmpeg:
ffmpeg -i `youtube-dl --youtube-skip-dash-manifest -g "https://www.youtube.com/watch?v=f9ALdmDLPGU"` -c copy -flags +global_header -f segment -segment_time 20 -segment_format_options movflags=+faststart -reset_timestamps 1 "%d.mp4"