It can be useful because when you're watching a video where nothing is moving, you know the video hasn't frozen; and if you transcode the video to another format (upload to youtube, for example) the data is preserved.
Of course, even better would be if the cops' cameras recorded to a standard format that included accurate timecodes and secure digital signatures - and that same format could be viewed by most video players.
It can be useful because when you're watching a video where nothing is moving, you know the video hasn't frozen; and if you transcode the video to another format (upload to youtube, for example) the data is preserved.
Of course, even better would be if the cops' cameras recorded to a standard format that included accurate timecodes and secure digital signatures - and that same format could be viewed by most video players.