go get github.com/sbuss/govtvfetcher/cmd/govtvfetch
Find the video you want from sfgovtv.org, eg "http://sanfrancisco.granicus.com/MediaPlayer.php?view_id=20&clip_id=31014". Then just call the fetched:
govtvfetch -uri 'http://sanfrancisco.granicus.com/MediaPlayer.php?view_id=20&clip_id=31014'If will download the file in chunks to /tmp and then combine them into your current directory.