You mean that vid from Ottawa that youtuber was streaming? Those black boxes looked like some type of comms interception or suppression system being loaded by those men in tactical black into a bldg connecting to Trudeau's govt office. Some mil comms anon seemed fairly certain about that incident. Unless you are talking about another video.
Also, those sonic or other types of crowd dispersal systems are deployed at street level and from a mobile tactical platform. Much larger than those boxes in the Ottawa video.