On it's surface making the footage not immediately public isn't a bad idea. The classic example would be a swat team showing up at the wrong house, busting down the door, and having video footage of John Q Citizen in his birthday suit. As long as there is a process for getting access to the footage that's impartial, that's fine.

What's really needed though is a way to escrow the footage. This is a solved problem in the tech world. The stream should be stored off site, cryptographically signed (public sig), in the control of a third party (though still a government entity, not a private corporation). Otherwise you'd be asking the criminals[1] to hold onto the evidence.

[1]: Not that all or even most police are criminals, but in the case where a police officer does commit a crime they are de facto criminals.