Most CCTV quotations compare camera counts. The numbers that decide whether the system is useful are pixel density at each position and how many days of footage you keep. This page sizes both, and shows the six mistakes that turn an expensive system into unusable footage.
Change the codec and the recording mode before you change the resolution. They move the number far more.
Based on H.264 reference bitrates at 25 fps, scaled for codec, frame rate and recording mode. Drive sizing adds 10% headroom; filesystem overhead means a drive never delivers its full labelled capacity. Motion and AI figures assume typical commercial activity — a busy retail floor records far more than a store room.
Camera prices are what get compared. These are the parts that decide whether it works.
By position, with the lens matched to the distance — not one model repeated across the whole site.
Channel count with room to grow, and enough total incoming bitrate for every camera at once.
Rated for continuous write. A desktop drive in a recorder fails, usually silently.
Sized on the night-time load, when infrared raises draw sharply.
Solid-copper Cat6 for IP, or the existing coax if you are upgrading in place. Never CCA under PoE.
Recorder, switch and network. A UPS on the recorder alone still loses every camera.
Only if someone actually watches live. Recording and monitoring are different designs.
Useful, but it is also the attack surface. Change every default password at commissioning.
Cuts false alarms and storage. Needs camera and recorder support on both ends.
The honest trade-offs.
| Consideration | Dome / Eyeball | Bullet | PTZ | HD Analog (coax) |
|---|---|---|---|---|
| Best for | Indoor, lobby, corridor | Perimeter, gate, long range | Large open areas, live operator | Reusing existing coax |
| Aim direction visible | No — discreet | Yes — obvious | Moves visibly | Depends on body |
| Typical lens reach | Short to medium | Medium to long | Longest, optical zoom | Short to medium |
| Vandal resistance | High | Moderate | Moderate | Varies |
| Needs an operator | No | No | Yes — or it stares at one spot | No |
| Cabling | Cat6 / PoE | Cat6 / PoE | Cat6 / PoE | Existing coax |
| Relative cost | Low | Low to moderate | Highest | Lowest to upgrade |
Cable routes to every camera position. Measure the actual route, not the straight line. Routes typically run 30–50% longer than they look on a drawing, and Ethernet stops working past 100 m.
A location for the recorder. Ventilated, secure and lockable. A recorder sitting on a reception desk is the first thing an intruder removes.
Mains power and UPS capacity. For the recorder and the switch, not just the recorder.
Lighting survey after dark. Walk the site at night before quoting. Daytime surveys miss backlight, unlit gaps and reflective surfaces — and those decide the camera choice.
Mounting surfaces and heights. Identification cameras go low and tight. Overview cameras go high and wide. Mounting everything at the same height is how you end up with footage of the tops of heads.
Network capacity if sharing with office traffic. Cameras on the office VLAN means one faulty camera can take down the office network. Separate them.
Internet upload speed, if remote viewing matters. Remote access uses your upload direction, which is usually the slower one.
Drive replacement. Surveillance drives run continuously and wear out. Budget for replacement rather than discovering a failure the week you need footage.
Electricity. Cameras, switch and recorder run 24/7. Modest per camera, real across a hundred of them.
Cleaning. Dust and spider webs on the lens defeat an expensive camera completely. In Bangladeshi conditions, outdoor domes need cleaning on a schedule, not on complaint.
Firmware and password maintenance. Security updates matter on anything internet-reachable. This is ongoing work, not a one-off at handover.
Re-aiming after building changes. New signage, new racking, a new partition wall — any of them can blind a camera that was correctly aimed at commissioning.
A 4K camera covering a whole car park identifies nobody.
Match the lens to the distance, per position.Infrared raises draw after dark and cameras drop out every evening.
Size on the night-time load, plus 25% headroom.Produces excellent footage of the tops of people's heads.
Identification low and tight, overview high and wide.Not built for continuous write. They fail silently.
Surveillance-grade drives only.The most common route to a compromised site.
Change every credential at commissioning and record it.The switch loses power, every camera goes down, and the recorder faithfully records nothing.
Protect cameras, switch, recorder and network together.Authorized import, genuine firmware, local warranty and service through our branch network.
Dome, eyeball, bullet, PTZ and full-colour night cameras across ZKTeco, Hikvision, Dahua and IMOU.
4 to 32 channel, including recorders that take analog and IP together for staged upgrades.
Solid-copper Cat6, patch panels and PoE switches sized for camera loads. See our PoE network guide.
Keeping the whole recording path alive through load-shedding. See our power backup guide.
Wide views, yards, corridors. Tells you an event happened, not who.
Staff areas, known-vehicle gates. Useful internally, weak as evidence.
Entry doors, tills, cash points. Mount low and tight.
Largest files. Use when older recorders or apps must decode it.
Check recorder and phone app support.
Biggest saving on static views such as corridors and store rooms.
Largest storage. Required by many tenders and regulators.
Large saving on quiet sites; little saving on a busy retail floor.
Biggest saving and fewest false alarms. Needs support at both ends.
Never through glass — the reflection washes out the picture.
Repositioning the camera is free and usually works better.
The question that decides a CCTV design is not how many cameras. It is what you need to SEE at each point. Answer these four in order.
Pixel density at the target is what matters, not the sensor. A 4K camera covering a whole car park identifies nobody; a 2MP camera tight on a doorway identifies everyone. Match the lens to the distance first.
The IR reflects straight back off the pane and washes the image out. Mount it outside the glass, or turn IR off and light the area.
You get a silhouette. Reposition it, or specify wide dynamic range — repositioning is free.
Codec and recording mode move the number far more. H.265+ at motion-only is a fraction of H.264 continuous, at the same resolution.
Consumer drives are not built for continuous write. They fail, usually silently, and you discover it the week you need the footage.
Internet-exposed CCTV with factory credentials is the single most common way a site is breached. Change them at commissioning and record them properly.
What you need to SEE at each point decides the camera. Everything else follows from that.
Dome and eyeball bodies are discreet, vandal-resistant and do not advertise which way they are pointing.
Every product above is one DigiMark Solution imports, stocks and warrants. Pricing is quotation-based and depends on quantity and configuration — request a quotation or ask on WhatsApp.
What a CCTV tender must state for quotations to be comparable instead of merely cheap.
| Sector | What to specify | Typical scale | The clause bidders exploit |
|---|---|---|---|
| Government / defence | Retention period in days; pixel density at identification points; authorized-distributor certificate; local service SLA; audit-log retention | 50–500 cameras | Retention in days. Bidders quote a smaller drive and meet the camera count exactly |
| Garments / factory | Camera count by zone; IP rating for dusty floors; night-time PoE budget; production-line coverage | 100–400 cameras | State IP rating per position or you will be quoted indoor bodies for a dye house |
| Bank / financial | Identification-grade at tills and ATM; continuous recording; retention per regulator; tamper alarms | 20–80 cameras | Specify identification grade at named positions, not an overall megapixel figure |
| Hospital | Corridor and entrance coverage; privacy exclusions for wards and treatment areas; 24/7 operation | 50–200 cameras | List the privacy-excluded areas explicitly — it is a compliance issue, not a design preference |
| School / campus | Gate and perimeter; playground coverage; controlled access to the recording system | 30–150 cameras | State who may view footage and from where |
| Retail / showroom | Till-level identification; stock area coverage; discreet indoor bodies | 10–60 cameras | Till positions need identification grade; the rest usually does not. Say which is which |
It depends far more on codec and recording mode than on camera count. Sixteen 4MP cameras recording continuously in H.264 need several times the storage of the same sixteen cameras in H.265+ on motion detection. Use the calculator above — it converts resolution, frame rate, codec and recording mode into a drive size with headroom already added.
They are compression standards. H.265 produces roughly half the file size of H.264 at comparable quality, and H.265+ adds scene-aware optimisation that reduces it further on mostly-static views such as a corridor or a store room. The trade-off is that older recorders and some phone apps do not decode H.265. Confirm your recorder and your viewing devices support it before specifying it.
If the building already has coax from an older system, HD analog gives you 2–5MP over that existing cable with no rewiring, and it is the cheapest genuine upgrade. If you are running new cable anyway, use Cat6 and IP — you get PoE, easier expansion and better analytics. The deciding factor is the cable already in the wall, not the technology.
Megapixels alone tell you nothing. What matters is pixel density at the thing you want to see, which depends on the lens and the distance. A 4K camera covering an entire car park identifies nobody; a 2MP camera tight on a doorway identifies everyone who walks through it. Decide per position whether you need to detect, recognise or identify, then match the lens.
Almost always PoE budget. Infrared illuminators raise power draw sharply after dark, so a switch sized on the daytime figure runs out of budget at dusk. Size the switch on the night-time load and leave 25% headroom.
Yes, through the manufacturer app. Two things matter before you rely on it: change the default passwords at commissioning, because internet-exposed CCTV with factory credentials is the most common way a site is compromised; and confirm your upload bandwidth, because remote viewing uses your upload speed, which is usually the slower direction.
Without a UPS, recording stops. A UPS on the recorder alone is not enough either — if the PoE switch loses power the cameras go down regardless. Protect the whole path: cameras, switch, recorder and the network between them.
Seven to fifteen days covers most commercial sites. Thirty days or more is common in tenders, banking and government work. State the retention period in days in your BOQ — it is the figure bidders quietly reduce to win on price, by quoting a smaller drive while matching your camera count exactly.
Figures as of September 2026. Confirm with a quotation.
Free site survey across Dhaka and Chattogram, including a night-time lighting check. Our engineers confirm the design before anything is quoted.