Estimate body camera storage from measured file sizes, recorded hours, approved retention assumptions, usable capacity, and recovery needs. Includes original worked examples and a purchasing worksheet approach.
Body camera storage should be calculated from recorded work, not guessed from the number of officers. Two departments with the same camera count can produce very different amounts of video. Their recording hours, selected modes, retention requirements, held incidents, and backup arrangements may differ substantially.
The most useful starting point is a measured sample from the camera and settings the department intends to use. This guide shows how to turn that sample into a clear estimate, check the assumptions, and ask Martel for a package configuration that fits the workload.
Compare Martel police camera packages or review the Crime Cam as you prepare the figures. All calculations below are examples. Their recording rates and retention periods are stated assumptions, not Crime Cam specifications or retention recommendations.
First, the camera needs enough onboard space for its assignment before the next successful download. Confirm the actual supplied capacity and how much is available for recordings. A large archive at the station cannot prevent a camera from filling during use.
Second, the working archive needs room for recordings kept under the approved schedule. That requirement includes routine recordings and material held longer for a particular reason. The department should decide those requirements through its responsible policy, records, and legal processes before treating a capacity estimate as final.
Third, the recovery arrangement needs enough space and an appropriate process to protect the required copies. Backup capacity is not automatically interchangeable with working-archive capacity. The role of each storage device should be stated in the proposed design.
Use the intended camera, recording mode, compression choice, quality setting, and ordinary operating pattern. Record training scenes that resemble actual work without using real incidents. Include movement, changing light, and typical audio conditions. Keep a record of the settings with the samples.
For each sample, note its duration and file size. Use consistent units, such as gigabytes and recorded hours. Divide size by duration to obtain gigabytes per recorded hour. A thirty-minute sample that occupies one gigabyte represents an observed rate of two gigabytes per recorded hour for that sample.
Use several samples when sizes vary. A static scene and a scene with substantial movement may not produce identical sizes under every compression setting. For planning, retain the range and explain which figure is used. An average without its sample conditions can create false confidence.
The Crime Cam page lists several recording resolutions and H.264 or H.265/HEVC choices. Those details help define the test configuration, but resolution alone does not tell you the final file size. Compression, quality settings, scene content, and the device’s implementation can affect the result.
Avoid borrowing a generic internet file-size estimate and presenting it as a Crime Cam rate. Measure the supplied device or obtain a confirmed rate for the exact configuration from Martel. Keep the sample files so the estimate can be checked later.
Also verify playback of the selected mode on the receiving and review computers. A setting that reduces file size may still require a playback environment that the department needs to prepare. Evaluate recording detail, storage, runtime, transfer, and review together.
Daily recorded data equals the number of active cameras multiplied by average recorded hours per camera per day multiplied by measured gigabytes per recorded hour. This is a data-production estimate, so the hours should describe actual recording, not merely the full duty period unless the plan records continuously.
Routine retained data then equals daily recorded data multiplied by the number of days in the approved routine retention assumption. Add separate estimates for material retained longer, operating reserve, expected growth, and any other required files. Calculate backup needs according to the approved recovery design.
Write every input beside the answer. A total such as twelve terabytes is not meaningful without its assumed recording hours, rate, and retention period. An estimate that exposes its assumptions can be revised as the deployment learns from real workload.
Assume six cameras each produce two recorded hours per day. Assume the measured planning rate is two gigabytes per recorded hour. Daily production is six multiplied by two multiplied by two, or twenty-four gigabytes.
For an illustrative sixty-day routine-retention assumption, twenty-four gigabytes per day multiplied by sixty days equals 1,440 gigabytes, or 1.44 decimal terabytes. That figure describes only the routine footage under those assumptions. It excludes longer-held incidents, exports, growth, operating reserve, and backup.
If the agency later measures three recorded hours per camera instead of two, daily production rises to thirty-six gigabytes. The same sixty-day assumption would then require 2.16 decimal terabytes for routine footage. One changed input has increased that part of the estimate by half. This is why recorded hours deserve careful measurement.
Assume twelve cameras each produce three recorded hours daily. Assume the measured planning rate is 3.6 gigabytes per recorded hour. Daily production is twelve multiplied by three multiplied by 3.6, or 129.6 gigabytes.
For an illustrative ninety-day routine-retention assumption, the result is 11,664 gigabytes, or 11.664 decimal terabytes. Again, this is a calculation example rather than a statement about Crime Cam file sizes or required retention. The archive design must add the other relevant categories.
If the organization plans a separate recovery copy of that routine footage, it needs to evaluate the additional capacity and copying process separately. It should not describe the same physical space as both the complete working archive and an independent recovery copy.
A confirmed bitrate can provide another planning method. For decimal units, gigabytes per recorded hour are approximately megabits per second multiplied by 0.45. This follows from eight bits per byte and 3,600 seconds per hour. File overhead and variable-rate behavior can cause measured files to differ.
For example, an assumed eight-megabit-per-second stream corresponds to approximately 3.6 gigabytes per hour. That is an arithmetic illustration, not a claim that Crime Cam records at that bitrate. Use a measured rate whenever possible and confirm whether a supplied bitrate is fixed, variable, average, or maximum.
Do not mix megabits and megabytes. The difference is a factor of eight, which can create a large storage error. Have a second person review units before the estimate becomes part of a purchasing document.
Drive manufacturers commonly label storage using decimal capacity units. Computer tools may display capacity using a different convention or label. Formatting, system use, and the selected storage configuration also affect the space available for files.
For purchasing, ask for a usable-capacity figure stated in a consistent unit and tied to the actual configuration. Record whether that figure is before or after the operating reserve. This avoids comparing a raw disk label from one proposal with usable archive space from another.
A package title is not a capacity engineering report. Martel’s package pages identify equipment and stated storage sizes, but the quote should explain the supplied disk arrangement and its intended role. Ask for clarification where a title, image, and detailed contents use different descriptions.
RAID configuration can trade raw capacity for particular fault-tolerance characteristics. The exact result depends on the number and size of disks and the selected arrangement. Do not calculate usable archive space simply by adding the labels on all installed drives.
Ask the supplier to state the chosen configuration, usable space, supported failure behavior, and maintenance procedure. The department’s responsible IT staff should review those details against its requirements. A description such as RAID storage should lead to specific questions rather than a blanket assumption of protection.
RAID is also different from backup. It can address certain disk failures while the live system remains exposed to other problems, including accidental deletion or damage affecting the whole device. The recovery design must be considered separately.
Routine retention is only part of a body camera archive. Some material may need to be held longer under the organization’s approved process. The department should estimate that category using its expected workload and revise the estimate as real experience becomes available.
Record the assumed number of held events, average size per event, and expected duration of the hold. Do not use the routine deletion date as a capacity assumption for files that are under a separate preservation requirement. The storage estimate should reflect the way the organization actually classifies material.
Where reliable historical figures are unavailable, label the assumption and plan a review date. An uncertain estimate can still support planning if it is visible and revisited. Hiding uncertainty inside an exact total makes later growth harder to explain.
An archive should have room for normal variations, maintenance, and the time needed to address a capacity warning. The appropriate reserve depends on the system and organization. Ask responsible technical staff to set it and explain the amount in the proposal.
Do not count every available byte as routine capacity and then assume staff can respond instantly when storage fills. Define the warning threshold, the person who receives the warning, and the approved response. Include how long equipment procurement or configuration changes may take.
Use the same reserve method when comparing proposals. If one estimate includes twenty percent reserve and another includes none, their headline capacity figures describe different planning assumptions. The comparison should make that difference visible.
Adding cameras increases data production, but changes in recording practice can also increase it. Longer recording periods, a higher-quality mode, additional still photos, and more retained events can all affect storage. Record which changes are expected during the planning period.
For illustration, increasing a twelve-camera deployment to eighteen cameras increases camera count by fifty percent. If recorded hours and file rate remain unchanged, routine data production also increases by fifty percent. If recording hours increase at the same time, calculate that effect separately.
Ask how storage expansion would be performed in the proposed design. Identify whether expansion requires replacement hardware, migration, downtime, or additional setup. The answer helps purchasing compare initial cost with the likely next step.
Space is not the only storage constraint. The receiving system must move and verify the expected data within the available operating window. A large archive that cannot receive the shift’s files in time still creates a daily problem.
Test a representative batch with the intended docks, computer, and storage destination. Observe the amount of data, completion time, staff actions, and any exceptions. Keep the result with the capacity estimate so the proposal addresses both room for files and the work of moving them.
If backup runs during the same period, test that combined routine as approved by responsible staff. Avoid promising throughput from component labels alone. The complete installed path determines the actual workflow.
Choose a training recording, place it through the approved receiving and recovery process, and have authorized staff demonstrate restoration to an approved test location. Check that the restored file plays and corresponds to the expected recording. Document the procedure and result.
The test should answer practical questions: who can initiate recovery, where instructions are kept, what equipment is needed, and how long the organization can tolerate the working archive being unavailable. These are operating decisions rather than camera features.
Schedule review according to the organization’s approved maintenance plan and repeat affected checks after significant changes. A recovery process that was demonstrated once on old equipment should not be assumed unchanged after a storage migration.
Create one row for each data category. Routine footage should show camera count, recorded hours, measured rate, retention assumption, and calculated total. Longer-held material should have its own size and duration assumptions. Add exports or other required files only where the organization actually stores them.
Then record usable working capacity, reserve, expected growth, and the separate recovery-copy requirement. Include the source and review date for each assumption. The result should distinguish measured inputs from estimates and policy decisions.
Have operations review recording hours, records staff review retention assumptions, IT review usable capacity and recovery design, and purchasing review the quoted equipment. This distribution of review helps prevent a camera-count assumption from silently becoming the entire storage plan.
Martel’s 6-officer and 12-officer listings describe workstation and local storage equipment alongside cameras and docking. Larger choices are available through the police camera category.
Send the worksheet assumptions with the quote request. Ask Martel to identify the current supplied storage devices, usable capacity, RAID arrangement where applicable, and intended role of each device. Confirm setup and support responsibilities. Do not assume that package camera count alone establishes the right archive size.
Choose a sample duration long enough to include the types of scene the department expects to record. A camera facing an empty wall is a poor substitute for an assignment involving walking, changing light, and conversation. Use staged activity with volunteers and keep the setting, recording mode, quality, and compression choice documented beside the files.
Record the actual duration from the file information or approved playback tool. If the camera splits a recording into multiple files, include every part that belongs to the sample. Confirm how the supplied device handles file segmentation rather than assuming one event always equals one file. Add the sizes of the relevant original files before calculating the observed rate.
Use a consistent unit for the calculation. A worksheet may use decimal gigabytes for planning, but it should explain that choice. If the computer displays a different convention, have technical staff convert consistently. Record the source measurement so a later reviewer can reproduce the arithmetic instead of trusting an unexplained number.
Create several samples if recording conditions vary substantially. Keep the smallest, typical, and largest observed rates with their conditions. The planning rate should be an explained choice from those observations. Do not present a sample average as a guaranteed maximum for every future scene.
A short training sample can still support an estimate if its limits are understood. Suppose a twenty-minute sample occupies 900 decimal megabytes. Twenty minutes is one-third of an hour, and 900 megabytes is 0.9 decimal gigabytes. Dividing 0.9 by one-third produces an observed rate of 2.7 gigabytes per recorded hour for that sample.
If twelve cameras each record two hours per operating day at the illustrative 2.7-gigabyte rate, daily production is 64.8 gigabytes. For a purely illustrative sixty-day accumulation, the routine total is 3,888 gigabytes, or 3.888 decimal terabytes. These numbers exclude recovery copies, held material, exports, reserve, and any other required data.
This example does not state a Crime Cam file size or an approved retention period. It demonstrates how to convert a measured short recording into a planning input. Replace every example input with the proposed device’s observed rate and the organization’s approved workload and retention assumptions.
Check the result with a second sample of a different duration. If the calculated hourly rates differ, retain both results and investigate the conditions rather than silently choosing the smaller number. A variable workload can justify a range in the estimate, with the selected capacity based on an explained planning assumption.
An agency may have patrol, event, and supervisory assignments with different recording patterns. Instead of applying one average to every camera, create a row for each assignment group. Record active cameras, recorded hours per day, measured rate, operating days, and the retention or preservation assumptions applicable to that group.
For illustration, four training cameras recording one hour daily at two gigabytes per hour produce eight gigabytes per day. Another eight cameras recording three hours daily at the same illustrative rate produce forty-eight gigabytes. Together they produce fifty-six gigabytes, even though a simple twelve-camera average might obscure the different operating patterns.
Keep assignment groups only when they improve the estimate. An excessively complicated worksheet can be difficult to maintain. Start with meaningful differences and revise the groups when actual deployment data shows that another distinction matters. Preserve the source and review date for each input.
Do not use staffing headcount as a substitute for active-camera count. Some employees may not carry a camera every day, while shared devices may serve more than one assignment. Use the recording workload and assignment schedule that the department actually plans to operate.
Daily data production and retention can use different time bases. A group may record on five days each week while its approved retention period is expressed in calendar days. State that distinction in the worksheet. Multiplying a five-day operating average by every calendar day without explanation can overstate production; ignoring weekend assignments can understate it.
One approach is to calculate total recorded data for a representative week, then use the organization’s approved planning method to estimate the relevant accumulation period. Document exceptions such as special events, additional shifts, or periods of higher activity. The exact method should be consistent and understandable to the purchasing and technical reviewers.
For a camera used every day, a daily average may be appropriate. For an irregular assignment, a schedule-based estimate may be clearer. Do not force different patterns into one formula merely to produce a neat total. The purpose is a useful estimate that can be compared with actual storage growth later.
Retention decisions should come from the organization’s approved process. This article supplies arithmetic examples and planning questions; it does not prescribe how long a department should keep a recording. Capacity should support the approved requirement rather than determine it by accident.
Material that remains under a separate preservation requirement may continue occupying storage after ordinary routine footage would have left the working archive. Estimate that material in a separate row. Include an explained event count, average size, and expected accumulation under the organization’s approved assumptions.
Suppose an illustrative routine archive totals eight terabytes, while separately held training-case examples are estimated to add one terabyte during the planning period. The combined working requirement is nine terabytes before reserve, growth, and other files. The example explains the categories; it does not predict a department’s case volume.
Avoid counting the same material twice without explanation. If held footage is included in the routine total during its initial period, the worksheet should describe how the additional long-term accumulation is estimated. The responsible records and technical staff can choose a method appropriate to their information and requirements.
Review the held-material assumption after deployment. A small number of long events or an unexpected accumulation can change the archive significantly. Keep the estimate linked to documented observations so capacity planning can respond before the available margin is exhausted.
Reserve percentages can be misunderstood. Adding twenty percent to a ten-terabyte workload produces a twelve-terabyte target, leaving two terabytes beyond the estimated workload. That reserve is twenty percent of the workload, but it is about 16.7 percent of the twelve-terabyte target.
If the design instead requires the workload to occupy no more than eighty percent of usable capacity, divide ten terabytes by 0.8. The result is 12.5 terabytes. These are different calculations. Neither example is a universal recommendation; the organization’s technical staff should select the appropriate reserve method for the proposed system.
Write the method beside the number. Use the same method when comparing proposals so one system is not credited with a reserve that another estimate omitted. Identify whether usable capacity has already excluded operating reserve, system use, or another allowance to avoid subtracting the same item twice.
Reserve should also connect to an operating response. Identify how capacity is monitored, when a warning is escalated, and how long the organization expects a supported expansion or repair to take. A percentage has practical value when it gives staff time to act through an approved process.
A sensitivity check changes one input at a time to show how much the estimate depends on it. Start with the proposed workload, then increase recorded hours while keeping camera count and rate constant. Next test a higher measured rate, then a larger deployment. Keep each scenario labeled so the purchasing team can understand the cause of the change.
For illustration, ten cameras recording two hours daily at three gigabytes per hour produce sixty gigabytes per day. Increasing recorded hours to three raises the result to ninety gigabytes. Keeping two hours but increasing the rate to four gigabytes produces eighty gigabytes. Increasing camera count to fifteen at the original inputs produces ninety gigabytes.
Those examples show why camera count alone is insufficient. A change in operating practice can affect data production as much as adding equipment. They also show why an estimate should retain its inputs: staff can revise one assumption without reconstructing the entire calculation.
Use the scenarios to ask useful purchasing questions. How would the proposed storage arrangement expand? Which configuration work is needed? Would the receiving workstation still handle the workload? Do not treat a sensitivity scenario as a forecast that the organization has committed to adopting.
If the organization retains both body-worn and vehicle recordings, calculate each source separately before combining their archive requirements. A multi-camera vehicle system may produce more than one view at a time. The total data includes the required simultaneous streams and their associated files, not merely one preview view.
Martel’s DC7 page describes front and rear coverage with local export and an optional station-upload path. The MDP6 page describes portable vehicle and field recording with removable memory. Those descriptions provide equipment context, but the file rate should come from measured samples of the selected configuration.
Keep the sample conditions and intended receiving method for each source. A body camera dock and a vehicle-upload arrangement may impose different return-time workloads. Combining their terabyte totals does not establish that the same receiving computer or network can process both at the required time.
Ask for confirmation of any proposed shared archive, indexing, or integration function. Do not infer common event identifiers or synchronized activation from the fact that the equipment is sold by Martel. The vehicle storage guide provides additional questions for the in-car portion of the plan.
Begin with a source column that identifies the recording group: body cameras, vehicle views, or another approved source. Add the active device count and the observed data rate. Record the sample date, settings, duration, and file sizes so the rate can be checked later.
Add the operating pattern and the approved retention assumptions. Show daily or weekly production using a consistent time basis. Then identify longer-held material, required working copies, and other known data categories separately. Avoid adding speculative categories that the organization does not actually store.
Next record the expected growth scenario and reserve method selected by responsible technical staff. Calculate the required working capacity and identify the separate recovery-copy design. Put usable quoted capacity beside the requirement using consistent units and explain the role of each supplied storage device.
Finish with unresolved questions, owners, and review dates. The worksheet should distinguish measured information, approved requirements, estimates, and supplier confirmations. That distinction is more useful than an apparently precise number built from hidden assumptions.
Use the organization’s approved monitoring process to measure actual data added during a representative period. Compare that amount with the estimate and identify significant differences. Additional cameras, longer events, different settings, more held material, or duplicate working copies may explain a change.
Do not revise the forecast from one unusually quiet or busy day without context. Look at an appropriate period for the deployment and record notable events. If a recording mode changed halfway through the period, separate the observations where practical so the new rate is not hidden in a mixed average.
Update the worksheet and the expansion forecast. If usable capacity is being consumed faster than expected, identify the approved response early. Storage maintenance should not rely on unauthorized deletion or an informal reduction in retention to make the numbers fit.
Keep the earlier worksheet as part of the decision history. The change from an initial estimate to measured deployment information is normal. A transparent revision helps the organization understand what it learned and why a capacity decision changed.
The recovery arrangement needs enough capacity for the material and versions the organization requires it to preserve. Ask responsible staff to define what is copied, how often, where it is kept, and what recovery point is expected. Those decisions affect both space and operating work.
Use a known training recording to demonstrate restoration to an approved test destination. Confirm its identity, duration, picture, and sound through the approved verification method. Record the equipment, account, operator, time, and outcome so another authorized employee can understand the result.
A successful restoration of one training file is useful evidence about the tested procedure. It should not be overstated as proof that every possible failure has been addressed. Have technical staff determine the required test scope and repeat affected checks after significant changes.
Keep recovery capacity distinct from spare working space. If one device serves a recovery role, its nominal size should not also be added to the working archive as though both uses were available simultaneously. The written design and quote should explain the intended arrangement.
Ask for the exact supplied devices, disk configuration, usable capacity, and the role of every storage component. Request confirmation of setup tasks, accounts, receiving paths, support scope, and the approved response to a device fault. Put essential requirements in writing and demonstrate the relevant workflow with training files.
Confirm that the proposed capacity estimate uses the selected recording mode and the organization’s workload. Identify the source of any file-rate assumption that has not been measured. Ask how the estimate would change if recorded hours or camera count increases within the planning period.
Finally, confirm ownership of monitoring and maintenance. The organization should know who reviews available space, receives warnings, requests expansion, maintains recovery copies, and updates the worksheet. A storage purchase becomes more useful when its capacity is connected to people who can maintain the intended process.
## Keep a record of assumptions that need confirmation
Every worksheet should identify inputs that are still provisional. A proposed recording rate, an unconfirmed number of active cameras, an estimated amount of held material, and an approved retention requirement do not have the same status. Label them clearly and assign follow-up to the person who can supply or approve the information.
For a vendor-provided rate, request the recording mode, quality, compression, sample conditions, and whether the figure is an average or another measure. For a department estimate, record the source period and any unusual assignments. That context allows later staff to understand why the number was chosen.
Before purchase approval, review the unresolved inputs with operations, records, and technical staff. Replace assumptions with confirmed information where available. If an estimate must remain, explain the planning allowance used and schedule a review after deployment. A defensible calculation can include uncertainty when that uncertainty is visible.
Keep the final storage calculation, quote, equipment configuration, and acceptance results together through the organization’s approved document process. Record the usable capacity and the role of each device as installed. The resulting reference should describe the equipment in service, not merely the configuration initially discussed.
When settings, devices, recording hours, or retention requirements change, update the worksheet and repeat affected checks. Preserve the earlier decision record so the reason for expansion remains understandable. This makes the storage plan a maintainable operating document rather than a number that becomes disconnected from daily work after the purchase.
A final arithmetic check should be performed by someone other than the worksheet’s author where practical. Confirm units, camera count, recorded hours, retention assumptions, usable capacity, reserve method, and the separate recovery requirement. Record the review date and unresolved inputs. This small check can catch a unit conversion or double-counted capacity before it becomes part of a purchasing decision.
Divide the usable gigabytes by the measured gigabytes per recorded hour. At a purely illustrative two gigabytes per hour, one thousand gigabytes represents five hundred recorded hours before other allowances. Actual results depend on the supplied configuration and measured recording rate.
Only when the proposed design actually uses them as combined working capacity. If one is intended for recovery copies or another role, adding both as available archive space misstates the design. Ask for a clear explanation in the quote.
The effect depends on the selected compression and quality implementation, recording hours, retention, and storage design. Measure the mode that meets your recording requirement and calculate from that result. Avoid choosing a setting from a general assumption alone.
The organization should establish its required retention and preservation process through the appropriate responsible staff. Storage should then be sized to support that process. This equipment article does not set a legal or organizational retention schedule.
Review actual daily data production, held-material growth, available capacity, transfer exceptions, and the results of approved recovery tests. Compare those observations with the planning worksheet and revise assumptions before capacity becomes urgent.
Use the buyer’s guide, local-storage guide, docking guide, and system-cost guide for the surrounding decisions. Request a Martel written quote with the worksheet and your intended rollout size.
