The first in-car video systems appeared in patrol vehicles almost 20 years ago. In the time intervening, conventional wisdom would dictate that a standard emerge and the vendor community embrace it. As with so many things, conventional wisdom was wrong. Recently, the IACP
released a document to help police executives make informed decisions when setting out to buy mobile video equipment.
This report, called In-Car Video Camera Systems Performance Specifications: Digital Video Systems Module, provides very specific and technical requirements for all facets of mobile video equipment. When paired with the IACP’s 2005 publication, The Impact of Video Evidence on Modern Policing, decision-makers have an excellent resource to make an argument for the acquisition of this equipment, write the policies for its use, and ask the right questions of potential vendors. Both reports are available for download from the IACP Web site. Evolutionary Technologies
Most of us remember the passing of Constable Darrell Lunsford, even if we don’t readily recognize the name. Constable Lunsford, a patrol officer in Nacodoches County, Texas, has the unfortunate distinction of being the first law enforcement officer to have his own murder recorded on his patrol car camera.
Lunsford made a traffic stop of a vehicle he suspected was transporting drugs. His instincts were dead on. The car’s three occupants assaulted and overcame him, killing him with his own sidearm. The video recording of the incident was instrumental in identifying, arresting and convicting the killers.
That was in January 1991. In the almost 19 years intervening, in-car video has become commonplace in patrol cars, although the flavors of the equipment vary widely. Then, the VHS cassette was the most common recording medium. VHS recorders/players were cheap and plentiful, and there was no reason not to base the systems of the day on that standard. Continued use, however, revealed some of the weaknesses of VHS tape.
Some recorders/players “ate” tapes, and the tape mechanisms eventually wore out, often taking their video evidence to the grave with them. Tapes not completely erased before being re-used could retain portions of their previous recordings. If a tape got too close to a magnet, accidentally or otherwise, the recording on it was damaged or deleted entirely.
As with computer storage media, new standards have emerged, come into common use, and been supplanted by even newer gear. In 1991, the music CD was barely 10 years old and required expensive commercial equipment to produce. Since then, we have worked our way through both 5.25-inch and 3.5-inch floppy disks, music and data CDs, digital tape, DVDs, SD memory cards and memory sticks, Blu-Ray disks, flash drives, hard disks with capacities from 10 MB to 20,000 times that, and now solid state drives. Most of these storage media have been incorporated into a video system at some point. It is no great surprise that buyers are confused.
Other aspects of in-car video gear include the physical configuration of the system. Early systems were little more than a camcorder and a wireless microphone attached to the dashboard and windshield with tie-downs and suction cups. Subsequent designs involved the entire mechanism in an enclosure attached to the headliner of the car, a camera with the recorder in the glove compartment or trunk, or the recorder built into the dashboard, replacing the AM-FM radio.
Officer / Occupant Safety
This was the first issue to be addressed by the IACP’s specification. Equipment complying with the specs has to withstand a 50g (50 times its own weight) pull from a minimum of three axes, for a minimum of one second. The three axes simulate front, side and rear collisions. The equipment can’t come free or shift into an airbag deployment zone. All corners have to be padded or smoothed so as not to cause injury if they come into contact with a vehicle occupant. The devices also have to be insulated against burns from hot-running components.
The spec requires that controls be as simple as possible and not provide excess distraction for the operator. Buttons and knobs must be large enough to be operated by someone wearing winter gloves. The controls are to be illuminated, preferably backlit, and dimmable over a range from bright to dark. Operators must be able to black out the system on command.
Some states have a requirement to notify a citizen who is being recorded by a patrol car camera. Compliance with this requirement is met by a specification that an indicator light be visible to the front and side of the car when the equipment is recording. The same spec provides that the indicator light be disabled if desired. Systems have to operate reliably between 0 F and +120 F.
Cameras have to incorporate automatic backlight compensation, autofocus, automatic exposure and automatic white balance. The backlight compensation is critical and often missing from budget systems. When the camera is facing the sun or the headlights from an oncoming car, conventional automatic exposure systems will stop down the lens so far that most activity is impossible to see. Backlight compensation senses this situation and actually opens the lens more so that figures in the foreground are visible.
Officers experienced with mobile video are familiar with the terms “performance stage” or “arena.” This is not so much a theatrical term as one to be aware of when conducting interviews or administering field sobriety tests. The performance arena is the zone visible to the camera, and has varied widely with different models and vendors. IACP’s spec requires a minimum field of view of 24 feet at a distance of 40 feet from the camera. This translates to a 40 degree angle of view in the horizontal plane. The camera can zoom in to any area on command from the operator, but most systems automatically return to the conventional wide angle view after a few seconds.
Metadata and Microphones
Metadata is “data about data.” If you think of the contents of a book as data, the book’s title, author, publisher, publication date and the page on which a particular piece of information is found are its metadata. Most everyone who has ever seen a patrol car video recording has seen metadata appear in the frame, such as the date and time when the recording was made, the name and/or number of the officer operating the vehicle, and sometimes whether the lights and siren are operating.
The IACP requires, at a minimum, that every frame of a recording contain metadata for date and time; operator identification; and indicators for the status of the siren, emergency lights, brakes and radio transmission. Some digital systems record even more types of metadata, such as the GPS coordinates of the vehicle, its speed, output from traffic radar, headlight status, whether seat belts are in use, and so on.
All of this information need not appear in the frame—if it did, there wouldn’t be any room for the picture. A properly designed system will provide for the constant recording of these data points with each frame, but each is selectable for display on playback. If the viewer wants to see the video on a “clean screen,” the recording can be played back with no metadata appearing at all.
Microphones have been a sore point with video system users. Many early systems and later systems targeted for low price points used analog wireless microphones that were unreliable and of poor quality. When the mics worked at all, the sound from them was muddy, broken up or just incomprehensible.
More advanced digital microphones are far more reliable. The sound from them is clearer, and their range is longer. They transmit a coded signal that may be on the same frequency with other mics in the immediate area (as will be commonplace when more than one officer is on the scene), but will only be recorded by the system to which it’s paired. The IACP specifications require this type of microphone.
Mics must have a line-of-sight range of at least 1,000 feet; have their power supplies, pickups and antennas incorporated into a single unit (no more little wire strung from the box to your shirt front, unless you want it that way); and automatically pair or synchronize with their designated recorder without any manual intervention by the user. The same mics must also be able to activate the in-car recorder remotely and be silenced without turning the recorder off. Minimum battery life is 15 hours passive (not transmitting) and 3.5 hours active.
Systems meeting the IACP spec activate when the operator pushes the “record” button in the car, when the emergency lights or siren is activated and when the operator pushes the “record” button on the wireless microphone.
Minimum requirements for recording capacity of a spec system are 3.5 hours continuous at 30 frames per second, with no dropped frames. Conspicuously absent is a specification for image resolution as measured in pixels. The authors of the report addressed this issue in a different fashion, and one that is arguably more relevant.
Some mobile video vendors have stressed their systems’ available recording time while giving less attention to the critical measure of resolution. This factor was even easier to hide because there are so many “standards” and ways of measuring resolution. Somewhat oversimplified, a standard broadcast image is about 640x480 pixels, or 307,200 dots to make up the picture. Go down to 320x240, which is close to the typical YouTube video, and you might think the image is only half as large. In fact, it’s one-quarter the size, at 76,800 pixels.
Some vendors market systems that record video at this resolution, which gives them incredible recording capacities as compared to higher-resolution models. The problem comes when you want to see detail in the image. Despite the video enhancement capabilities available in Hollywood, only a skilled forensic video technician can provide much more detail than what you see, and that requires time and expensive equipment. It’s much better to go with high-resolution images and re-think your archiving solutions.
The IACP spec doesn’t address pixels so much as performance. They have set out very specific test procedures and measurements for clarity, contrast, ability to capture moving objects and other parameters. These are fairly technical, but fudge-factor-proof. Regardless of the amount of pixels, lines of resolution or color depth built into a mobile video system, it will either pass these tests or it won’t.
The last area addressed in the IACP specifications, and the one that many law enforcement agencies overlook, is archiving. No matter what recording medium you select, you’re going to wind up with a lot of video. The first issue to consider is how long you have to keep it. Your state may mandate how long evidence must be retained for certain crimes, but most of them don’t. Setting a retention policy is a critical step in developing an archiving plan.
Once you have your retention numbers in place, you need to calculate how much video your agency is going to produce under that policy, how you will catalog and store it, and who will be responsible for responding to requests for copies and maintaining the chain of custody. When you provide copies, how will you distribute them? Will you charge for this service? Failing to think through this process before you start accumulating video content is an invitation to accusations of evidence mishandling.
The IACP standard details documentation and verification procedures to ensure that video evidence is not compromised during transfer from the car system to the archive, or while stored or copied. The specification speaks to this in general terms, because there are so many ways of maintaining this evidence. Whether your recordings are transferred by removing the physical media, through an Ethernet connection, or wirelessly, and how the recordings will be stored (on the original media or transferred to a computer server) will all play a role in developing your archiving policy.
This document performs a valuable service for law enforcement. Mobile video vendors actively participated in its creation and are now verifying or modifying their products to meet the specifications. When a video manufacturer represents its product as meeting the IACP specifications, you will know the system is worth examining.
Tim Dees is a retired police officer and the former technical editor of LAW and ORDER. He can be reached at firstname.lastname@example.org.
Photos courtesy of Tim Dees.