I keep seeing this complaint, but it doesn't make sense. Are people assuming that for every 1 police officer, they will hire 1 video reviewer to watch that officer for his entire shift? That's silly.
Any real-world application, would be local recording on the device. When an incident is reported, the police officer logs the time of his response just like he/she already does all the time. He/she turns in his camera, and any video corresponding to the officer's incident report is then archived and tagged to that incident. You don't need to save 12 hours of video per officer. You just need the time of the incident which will be very brief indeed. If you want more manual control of the evidence. Let the officer pick the video times he wants to log, submit it to evidence dept., evidence dept. fast-forwards through the video to simply verify the officer selected the right times to capture the incident (if not, kick it back to the officer to reselect his times and resubmit to the evidence dept.).
The result is 1) The officer is the only one picking out the video to archive, and no personal/private information will be submitted without the officer's consent. 2) Someone who isn't the officer is ALSO explicitly responsible for ensuring that a video of the incident was submitted to evidence that day. 3) You don't have 4 hours of video recording an officer just filling out paperwork.