How Nighttime Video May Crash Your Network

Author: Ethan Ace, Published on May 02, 2012

Nighttime video may crash your network. During the day, under ideal conditions, bandwidth remains relatively stable. However, when the lights go down, bandwidth changes can become severe, creating problems like lost video, degraded quality and network instability. In this note, we look at the causes and negative effects of these low-light issues, and give our recommendations for overcoming them.

Bandwidth Planning

Most surveillance networks are designed using average numbers (typically from daytime video) or manufacturer camera calculators. Both of these methods are, if not best case, optimistic, and do not account for nighttime spikes. In other video industries, such as broadcast and A/V, constant bitrate encoding is generally used, to provide more stable, predictable bandwidth consumption. In surveillance, this is not the case, as our poll shows most prefer VBR to CBR, due to the storage savings it provides. However, it creates the potential for spikes and variations which CBR does not.

The Causes of Nighttime Bandwidth Issues

VBR encoding, along with noise created when automatic gain controls turn on, are the typical causes of this issue. Under normal circumstances, video is relatively clear and noise-free. As light levels lower, however, gain controls activate to digitally increase the brightness of the image. This digital correction introduces noise, however, which results in increased video bandwidth.

The following video illustrates surging bandwidth when using an Axis Q1604:

The increase from ~100 kBps (800 kbps) to over 2800 (over 22 Mbps) illustrates just how potentially dangerous surges are.

Network Issues

A nearly 28x increase in bandwidth, as shown above, may easily overload the network. For example, assuming five cameras and a server are connected to a 10/100 switch, bandwidth surges at this level would quickly overwhelm the server's connection to the network, as it totals over 100 Mbps. This could result in a dropped connection, lost video, and other unexpected issues.

The issue is even more critical when using limited-bandwidth connections, such as wireless, 3G/4G, or cable/DSL. Even a moderate surge in bandwidth on a single camera may exceed available bandwidth, dropping the connection.

This is also dangerous when sharing the network with other services. If designers are accounting for 4 Mbps bandwidth on all cameras sharing a LAN with voice and data applications, these spikes may result in interruption to other services, potentially overwhelming switch interconnects and backbone connections.

Storage Issues

Surges may greatly reduce expected storage durations, as well. If storage calculations are based on cameras using average bandwidth, even moderate surges could cut days or even weeks off of retention periods. This is especially dangerous if the organization must meet state or federal regulations, such as the gaming industry, or in critical use systems, such as municipal or government security.

Solutions

There are two ways to account for these nighttime bandwidth spikes: setting bitrate caps on VBR streams, or using constant bitrate streams. We cover both of these in detail in our VBR vs. CBR streaming report:

  • Use VBR with a cap: The preferred way to handle these spikes is to set a maximum bitrate when using VBR streaming. This allows bandwidth to remain low most of the day, but increase to reasonable levels in low-light situations.
  • Use CBR: The second, though less preferred method for dealing with variations in bandwidth is to use constant bit rate streaming. This allows designers to account for variations, as bandwidth should generally not exceed the set rate. However, the CBR bitrate must be set high enough that degradation does not occur during bandwidth surges. This results in higher overall bandwidth and storage usage, where VBR would be lower during other times.

Using gigabit switches may also alleviate minor or moderate network issues, given their higher capacity. However, in larger systems, using 24- or 48-port switches, even gigabit links may not provide enough headroom.

Finally, gain management should be carefully considered. Most often, installers leave cameras set to default gain settings, which typically results in very aggressive levels, and resulting increased noise and bandwidth. Gain should be set to the lowest possible levels which still produce quality images, to avoid this. Users may see our automatic gain control test results for more information on setting gain, as well as comparisons of differing gain levels.

Comments : PRO Members only. Login. or Join.

Related Reports

Covert IP Camera Shootout - Axis, Hanwha, Hikvision, March, Vivotek on Mar 20, 2019
Covert cameras were one of the last holdout areas for analog cameras. However, in the past few years, IP / HD covert cameras have become...
Installation Course - Last Chance on Mar 14, 2019
This is the last chance to register for the March Installation course. This is a unique installation course in a market where little practical...
BCDVideo Expansion And Switch From HP To Dell Examined on Mar 11, 2019
BCDVideo says they have more than tripled revenue in the past 5 years and are continuing to grow, powered most recently by switching their lead...
Arcules Favorability Results 2019 on Mar 08, 2019
Arcules has amazing advantages. Tens of millions of funding from Canon. Unlimited access to Milestone's source code (see our test results). But...
Salient CompleteView 20/20 VMS Tested on Feb 27, 2019
In IPVM's last test of Salient 3 years ago, we found various problems and deficiencies. Now, Salient says their new CompleteView 20/20 "unified...
Security Installation Tools Guide - 22 Tools Listed on Feb 19, 2019
In this guide, we cover 22 tools that security installers frequently use. This is one part of our upcoming Video Surveillance...
Sales Cuts At Rasilient on Feb 19, 2019
Over the past 2 years, video surveillance storage specialist Rasilient has expanded its workforce significantly, aiming to build its own branded...
Axis IR Multi Imager Camera Tested (P3717-PLE) on Feb 18, 2019
Axis has released their first IR multi imager, the P3717-PLE, a repositionable model listing 360° IR illumination and flexible positioning,...
Ubiquiti Favorability Results 2019 on Feb 18, 2019
Ubiquiti has quietly grown into a $1+ billion annual revenue company, with offerings across wireless, wireline network and video surveillance (see...
Casino Surveillance Pro Interview: James Lathrop on Feb 15, 2019
James Lathrop has been working in casinos for almost 25 years. During that time, he says he has held "just about every job you can do in the...

Most Recent Industry Reports

IBM / Genetec Surveillance System Investigated Over Philippines Human Rights Abuses on Mar 22, 2019
A lengthy investigation into an IBM video surveillance project in the Philippines, raising concerns IBM helped local police conduct a bloody...
Eagle Eye Favorability Results 2019 on Mar 21, 2019
Eagle Eye has been the biggest spender in the cloud VMS market including (via their owner) acquiring Brivo for $50 million and CameraManager from...
Large Hospital Security End User Interview on Mar 21, 2019
This large single-state healthcare system consists of many hospitals, and hundreds of health parks, private practices, urgent care facilities, and...
Silicon Valley Cybersecurity Insurance Startup Coalition Profile on Mar 20, 2019
Many industry people believe cybersecurity insurance is not worth it, as the voting and debate in our Cybersecurity Insurance For Security...
Covert IP Camera Shootout - Axis, Hanwha, Hikvision, March, Vivotek on Mar 20, 2019
Covert cameras were one of the last holdout areas for analog cameras. However, in the past few years, IP / HD covert cameras have become...
Top Metrics For Ensuring Integrator Profitability - Statistics on Mar 20, 2019
How do integrators ensure the profitability of their projects? As part of our profitability study, 100+ integrators answered the following...
Avigilon Launches 'Renewed Products Program' on Mar 19, 2019
There are lots of 'pre-owned' cars but pre-owned IP cameras? While such programs are common in other industries, in video surveillance, they are...
Hanwha Tax Evasion Probe, Camera Division Implicated on Mar 19, 2019
A Hanwha group subsidiary was raided as part of a tax evasion probe. While a Korean news media report listed the raided entity as 'Hanwha...
Genetec Security Center 5.8 Tested on Mar 19, 2019
Genetec has released Version 5.8. This comes after a wait of more than a year that caused frustrations for many Genetec partners. Our previous...
Retired Mercury President Returns As Open Options President on Mar 18, 2019
Open Options experienced major changes in 2018, including being acquired by ACRE and losing its President and General Manager, John Berman who...

The world's leading video surveillance information source, IPVM provides the best reporting, testing and training for 10,000+ members globally. Dedicated to independent and objective information, we uniquely refuse any and all advertisements, sponsorship and consulting from manufacturers.

About | FAQ | Contact