Understanding the tech: 10 things to know about BWCs and storage

Here are 10 of the biggest technological considerations you should understand

This feature is part of our 2016 Guide to Body-Worn Cameras, a supplement that brings a sharpened focus to some of the most challenging issues related to the use of body-worn cameras and digital video evidence. To read all of the articles included in the guide, click here.

Rapidly advancing technology and social-political forces have made body-worn cameras (BWCs) the hot topic of the day in law enforcement circles. As with other revolutionary products and technologies, many vendors have jumped into the market, hoping to tap some of the billions of dollars that are already being spent on BWCs and their associated accessories and services. In order to make the most well-informed purchasing decisions, command staff must understand how the different cameras operate, what options are out there, and how they plan to use the technology.

Here are 10 of the biggest technological considerations you should understand.


As with other revolutionary products and technologies, many vendors have jumped into the market, hoping to tap some of the billions of dollars that are already being spent on BWCs.
As with other revolutionary products and technologies, many vendors have jumped into the market, hoping to tap some of the billions of dollars that are already being spent on BWCs. (Photo/iStock)

The earliest BWCs were typically “lipstick” cameras that were tethered to a recorder/battery module by a cable. Better engineering and the understanding that cops already have enough gear dangling off of them meant that the devices evolved into a single unit, with some variations and options between brands.

The typical design today is a small device about the size of a deck of cards with a camera facing outward in the upper corner or in the middle of the device. The opposite face of the device may have an LCD display for reviewing the video, a clip to hold it in place on the officer’s body, and/or controls to operate the recorder. Some vendors may also place the LCD display on the outward-facing side, so anyone being recorded can see exactly what is being recorded at all times.

The LCD display can be a nice feature, but it can also add cost, a slight amount of bulk, and can decrease battery life. Some models have the option of sending video to a synced smartphone via a wireless Bluetooth connection. Unless your officers often have a need to review video immediately, choosing a model with no LCD display may be a way to save money and battery.


Some models have provisions for attaching a camera to the officer’s head or shoulder, via an eyeglass frame, helmet, or ball cap clip, or an attachment to the uniform epaulet. A camera coaxially mounted on the officer’s head can provide more information than one on his chest, as it will show where the officer is looking, and may give a better perspective on the environment. It also requires a tethering cable.

In scenarios where you’re considering equipping motorcycle patrol with cameras, consider the fact that helmet-mounted cameras will show whether the officer is checking cross-traffic at intersections before proceeding through. This could be very important in a later accident investigation or personal injury lawsuit. 

Because we tend to move our heads more than our torsos, video from a head-mounted camera can be shaky and disorienting. Testing and review of videos from both body and head-mounted cameras makes it clearer which is best suited for your application.


Most BWCs have some type of visual indicator that the recorder is on, often via an LED on the camera or recorder. These are good for transparency in police operations, but can be a tactical hazard. The last thing a cop on a high-risk traffic stop or building search wants is a light to serve as a target. There is usually an option to switch off the activation light, but some are more easily operated than others.

How the BWC attaches to the officer might have the least amount of technology involved, but remains a very important factor. If the attachment isn’t secure enough, cameras will be lost and possibly broken frequently. Spring-loaded clips work well on belts, but not so much on shirt fronts. Every vendor seems to approach this problem differently. One employs a vest tailored to look like a sleeveless uniform shirt that is worn over the regular uniform, and also acts as a body armor carrier. The BWC slips into a custom-made pocket under the placket, with a plastic-reinforced hole for the lens. This is a novel and very secure way of carrying the BWC, but also ties you to a single uniform vendor and may require a costly new issue of carrier for every officer who will carry a BWC.

As with uniform fittings and choices, the method of mounting the BWC can be an individual preference. If possible, field test proposed devices and get feedback from the troops to ensure they will work as well as the vendor says they will.


Most BWC models have internal, rechargeable batteries that will power the recorder for three to six hours.

This amount of battery capacity is necessary because the devices are usually powered up for the entire duration of the duty tour, even if they’re not in record mode. As with most modern in-car camera systems, BWCs usually have a “pre-event” recording mode, where the last 30-120 seconds of video are saved in buffer memory. When the officer activates the recorder, the contents of that buffer are automatically appended to the front of the recording, though absent sound. Sound is usually not captured by the pre-event buffer for privacy reasons, but some vendors offer the option to record sound at all times.

No battery is 100 percent efficient, and all of them have service lives, usually measured in charge-discharge cycles. For example, after 500 charge-discharge cycles, the battery might have 80 percent of its original storage capacity. The original battery capacity exceeds the time the BWC is likely to run so as to make the battery still usable when its capacity declines.

Most devices recharge their batteries when they are placed into a charging dock, which often also downloads the recorded video into an archive and erases the recordings on the camera, so it’s ready for the next shift. A few may use a micro-USB cable, such as is common in many consumer electronics. A full charge can take anywhere between one and six hours.


Most BWCs have internal storage capacities of 16 or 32 gigabytes (GB). Like with all other electronics, the ability to store a lot of data in a very small space has improved dramatically. Most BWC recordings come in around 1 GB per hour, although that can increase substantially if a higher resolution is selected. Standard resolution is what you get on a non-HD TV screen, around 800 MB (0.78 GB) per hour. A 720p resolution quadruples that size, while HD-level 1020p resolution is sixteen times as much information. For most agencies, the standard or mid-level resolution is enough for their needs.

The only time internal storage is likely to be an issue is if you have a situation where an officer has to use the same BWC for multiple shifts without offloading the recorded video to a server. This doesn’t happen often, but if it’s a possibility, you’ll want to choose the largest internal storage capacity you can get.


The most common activation method is a user-operated button or switch on the device itself. Every vendor has a different idea of where and how these should work. At least one has a sliding shutter that activates the recorder when it is pulled down, exposing the camera lens. There is also a big colored dot next to the lens, drawing attention to it. This makes it evident to everyone when the camera is recording, and makes covert recording impossible, as the lens is covered when the recorder is off.

When choosing a BWC, keep in mind that the user may be wearing gloves when they need to activate the recorder, or they may be under intense stress, where fine motor skills deteriorate. The activation switch needs to be something the user can hit reliably under adverse conditions.

Some vendors have a provision for voice activation, so the officer can trigger the BWC into record mode just by speaking a command. The voice activation software is “trained” to the user’s voice, so the same command spoken by someone nearby won’t activate the camera. If that voice system is operating, it also draws power from the battery.

Newer BWC models are increasingly aware of their environment. Some will link to an in-car recorder system, activating when the car system does (or activating the car system when the BWC is triggered), or will power up when the car door opens. Obviously, the in-car and BWC systems need to be compatible to make this work.

Some will start recording if internal accelerometers sense the officer running, if there are violent movements (as would be the case if the officer was struggling with someone) or if he or she goes flat on the ground. It isn’t a big reach to expect future generations of BWC will be linked to a fitness bracelet or other device that monitors the user’s heart rate or other stress indicator. 


Another innovation is the formation of a network with the patrol car and/or or other BWCs in the vicinity. A network and the appropriate infrastructure (such as a strong wide-area data network) allow recordings to be broadcast to the patrol car and streamed to another car or to an operations center in real time. The operations center might also be able to trigger the recorder remotely. If other BWCs are included in the network, activation of one BWC could trigger activation of all the others within a defined perimeter, giving multiple perspectives on the same incident.


There has to be a way of getting the video recordings off of the BWC and into long-term storage. Most vendors use a combination dock and charger where the BWC resides when it isn’t in use. On being placed into the dock, a connected server downloads the recorded video and any other data and transfers it to a local server, or the cloud. When the data is downloaded and verified for integrity, the recordings are deleted from the BWC. At the same time, the battery is recharged and the device is made ready for the next user or next shift.

When an officer begins his or her shift, most systems have them log in to a computer connected to the dock. The system assigns a BWC to that officer for the shift, and encodes the officer’s name, badge number, and other data onto the internal memory. This “tags” every recording with that officer’s ID.

Another method, not often used, is to transfer the video wirelessly via any Wi-Fi connection the system has approved. This could be an opening for a security problem, but the larger issue is the time it takes for a large video file to move over a wireless connection. Hardwired connections are usually a better choice, but your situation may make the wireless option better.

Because of the size of the video files that will accumulate, most vendors have a system that stores the video in the cloud. The cloud is likely one or more servers located at huge server/data “farms” owned by companies like Google and Amazon.

Unless your agency is one in a high-tech locale or some other place with very high-speed internet connections, uploading that video is likely to create a logjam between your agency and the internet. Most of the U.S. makes do with internet connections averaging 11.4 Mbps, or megabits per second. If you have one of those 11.4 Mbps connections, uploading 1 GB of video will take about 14 minutes (there is a useful transfer time calculator available here, and that assumes no other online traffic during that time. Multiply that by however many cops will be using a BWC every day. Keep in mind that your download and upload speeds can be very different. To get an idea of what you’re dealing with, visit SpeedTest.org.

If you’re adopting a BWC system that uses the cloud, take into account this bandwidth problem. Your internet service provider may be able to suggest some solutions, including a bigger data pipe — for a fee, of course.

One possible alternative is to have officers take the BWCs home with them and use their own internet connections to transfer the video while recharging the devices. This method invites questions of security, as a user could conceivably delete video that was unfavorable to him, and copy it for another use (such as posting it on YouTube). Most of the BWC vendors incorporate safeguards to ensure against this, but it still invites an additional risk.


Metadata is “data about data.” Most of us are familiar with digital photography, but you might not know that nearly all digital cameras encode a significant amount of metadata with each photo file. The metadata can include the model and serial number of the camera, the exposure data, the time and date, and if the camera has a GPS function, the location where the photo was taken.

Video metadata can include all of this information, and much more. As mentioned above, most systems will tag each recording with the officer’s name or other identifier. The system might also be able to capture direction of travel, speed, and location sufficient to plot the physical path of the BWC on a moving map. If the BWC is networked with other recorders, it could include what other cameras were in the vicinity and whether they were recording.


Storage and management of video is the elephant in the room for any discussion of a BWC program. Unless you have a very small agency with a short retention policy on recordings, local storage is probably out of the question. Hard drive storage is cheaper than ever before, but a 10-cop department will still fill up a one-terabyte (1 TB) hard drive ($30-$50, plus the computer it’s connected to) in a bit over six months.

Your retention policy will have a huge impact on your storage requirements. If you decide you need to keep everything indefinitely, multiply the scenario above to fit the size of your operation. Know that buying new drives will be an infinitely recurring cost, doubled by the need to have backup copies of everything.

Most departments decide eventually to use the cloud. It’s usually preferable to use the BWC vendor’s video management solution, as opposed to trying a homegrown method. The vendor is going to have a front-end user interface that will be easier to use with more features than you can create locally. It will make the best use of whatever features the vendor has built into its products, and it’s probably going to be cheaper than other solutions.

The user interface is the indexing and viewing software you will be using to review videos. It’s critically important that this software is something you’re comfortable with and that it offers the features you need. If the software is difficult for you to use, you’re going to be wrestling with it every time you need to see or copy a video.

Features to look for include:

Search options. How many parameters can you use to locate relevant video clips? These might include an officer’s name, ID number, day, time, geo-coordinates, incident or case number, type of incident (field interview, traffic stop, crime report, etc.), length of clip, and others unique to your operation.

Security features. There needs to be several levels of security, each with rights that expand with the level. The basic level might give only the ability to see clips that user had made. A sergeant could have access to clips made by anyone in his squad. Only upper levels of security would permit the user to copy the video to external media.

Chain of evidence. Security should also track every action by every user, so that any change or copying can be tied to the person who did it. Users must be careful about signing in to the software and then walking away from the computer to do other things.

Thumbnail indexing. Many video management packages create a thumbnail, or small still frame, from the video every few seconds. This allows for quick review when you want to get to the portion of the video where the action takes place.

Viewing options. By default, videos usually play in a small viewing window, with the perimeter surrounded by metadata. There should be an option to view the video full screen.

Redaction capabilities. Before a video is released to an outside entity, you’ll often want to redact selected information, such as license plate numbers, faces of uninvolved witnesses, children, etc. Absent some automated processes, manually redacting this information, usually by blurring the details, is a tedious and time-consuming process. Some vendors offer auto-redaction features that will follow any object you designate, and redact it throughout the entire video.

Selective overlays. Most viewing software allows the user to overlay text on the screen that provides time and date, officer’s name, speed, whether emergency lights are on, etc. You should have the option to include or remove all of that information with every video. 

A retention policy governs how long you will keep each video recording before it’s deleted to save space and storage costs. The vendor will likely have a suggested retention policy, but this is something you will want to discuss with your prosecutor’s office and risk manager. If you have a pay-as-you-go storage contract, every retention decision is a compromise between cost and the risk of deleting a record you might need later.

Some vendors offer an “all you can eat” storage plan, often folded into a maintenance and service agreement. The vendor will charge you a fixed fee per month per user, no matter how much video that user might create.

Deciding which option is best will depend heavily on your agency size, your situation and needs, and on your retention policy. Most vendors estimate that each officer/user will generate about 1 GB of video per day, on average. Multiply the number of officer workdays in a month to get an idea of how much video data you will be generating.

For example, say you have a small agency where you field three officers on day shifts, three on evening shifts, and two on the overnight shift. That’s eight officer workdays each day, or 240 in a month. It will take you a little over four months to generate 1 TB (1024 GB) of video, assuming a 100 percent retention policy.

Amazon Web Services is the leader in online storage, and serves everyone from Netflix to the U.S. Government. Their standard storage rate is $0.03 per GB/month, with small price breaks as you start accumulating more video. At four months, storage will cost you about $30 per month, increasing by around $7.00 each month. A big advantage in using a massive service like Amazon is that your data is guaranteed to be backed up, with the redundant copies probably existing on different parts of the planet.

Storage is not the only cost associated with online video. You will also pay for bandwidth, which varies by how much you transfer from storage to your local computer. Expect to pay about $0.09 per GB downloaded.

Adopting a body-worn camera program can be an expensive and complex undertaking, but most agencies that have used the cameras don’t want to be without them. It’s a worthwhile investment that pays off on several levels.

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