How Much Megapixel Do You Need?

Published Mar 09, 2011 00:00 AM
PUBLIC - This article does not require an IPVM subscription. Feel free to share.

When selecting one's next recorder, a critical question for existing analog camera users will be: How much megapixel do you need? Answer wrong and your system could be handicapped for years. The lower the percentage the greater the success of HDcctv and incumbent DVR manufacturers; The higher the percentage, the stronger the need to migrate to more flexible options.

Limitations on Some Recorders

The fundamental issue is that many surveillance recorders have hardware limitations in the number of megapixel cameras they can handle. If a user needs to exceed that number, a new or secondary recorder must be bought. Most users will be unable (or find great difficulty) in authorizing such a step. What is bought today will be what likely remains in 2016 (or even later).

As a practical matter, this limitation is most common in HDcctv DVRs and incumbent manufacturer DVRs. For instance, many DVRs, like the just announced Pelco 4700/4800 units have a strict 2 MP camera maximum. New HDcctv DVRs have a similar limitation. Only a set number of HDcctv cameras will be supported (such as 2 HDcctv cameras and 8 analog cameras or 4 HDcctv cameras and 16 analog cameras, etc.). Even if you reduce the number of analog cameras used, it will be quite unlikely that you can increase your HD/MP camera connections.

Approach to Megapixel Migration

One school of thought, call it the 'exception' school, says that having higher resolution cameras at a handful of key areas (entrances, etc.) will be sufficient for most users. Assuming this approach, having a hard limit of 2 or 4 megapixel cameras on a 16 channel system should be sufficient.

Another school of thought, call it the 'ubiquitious' school, says that users will eventually standardize on higher resolution cameras and use them at nearly every location. Assuming this approach, hard limits on megapixel support is going to be a real problem.

For most real world users, the situation is likely to be somewhere in the middle. The majority will start with their existing analog camera base and then need to make some tough decisions:

  • Over the next 5 years, as older analog cameras die, what do they do? Do they replace them with new analog cameras or upgrade to higher resolution?
  • As they expand their system, what do they want to do for new cameras? 

If you take the 'exception' position, then you pick a few high profile cameras for upgrading to HD and replace cameras as they fail with new analog ones. Recorders with limited MP support will be satisfactory with this approach. Then, in 2016 or 2017, when you replace your DVR, you re-evaluate about moving the other 80% of the cameras to megapixel.

Tradeoffs of Different Options

By contrast, choosing recorders with flexibility in upgrading or eventually migrating all analog cameras to megapixel have their own tradeoffs. For instance, if you choose an HDcctv DVR, you may be locked in to only a few HD cameras but you eliminate the steps of integrating IP cameras or adding new cabling (or adapters for coax). Alternatively, if you choose a Hybrid DVR like a Pelco 4700/4800 with limited MP support, you have a restriction of upgrading cameras but the recorder may work with your existing client software (important for large multi-site organizations).

Here are the key pluses for each of the 3 options:

  • Limited Hybrid DVR (e.g., Pelco) - Backwards compatibility with UI / monitoring applications for other DVR
  • HDcctv / Analog DVR - No need to integrate IP cameras or deploy new cabling
  • 'True' Hybrid DVRs or encoders + VMS software - Migrate any camera to megapixel whenever you want

Generally, we find 'future-proofing' tactics to be wasteful. However, it is very obvious that megapixel is for real and is becoming the new de facto standard for quality video surveillance systems. To that end, picking a system that restricts megapixel expansion is risky. You need to ask yourself: "Can I accept only having a few MP cameras until 2016 or 2017?" and make a decision accordingly.