Technology Paper

Video Surveillance: The
Migration to Disk-Based

Digital video surveillance syste...
Video Surveillance: The Migration to
Disk-Based Storage

            Reaching the End of Tape                           ...
Video Surveillance: The Migration to
Disk-Based Storage

            Furthermore, this wealth of capacity pays          ...
Video Surveillance: The Migration to
Disk-Based Storage

                                             480, 10 fps), 32 c...
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Video Surveillance: The Migration to Disk-Based Storage

  1. 1. Technology Paper Video Surveillance: The Migration to Disk-Based Storage Introduction Digital video surveillance systems continue to proliferate at an impressive pace. In a recent report, according to IMS Research, the estimated worldwide market for video surveillance equipment was US$6.6 billion at the factory level in 2006 and is expected to grow to US$11.6 billion by 2011. Nearly one-third of the estimated revenue would be from hard drive-based surveillance DVRs and NVRs1. While post-9/11 security concerns certainly play a significant role in this phenomenon, the ongoing need for more efficient and effective surveillance systems is also driving the movement to digital-based solutions. To better understand the motivating factors behind this trend, it’s useful to break down the operational capabilities of video surveillance systems into three fundamental categories: • Quantity—volume of video streams a surveillance system can capture and store • Quality—image quality of video data, expressed in terms of frames per second (fps) and frame resolution (for example, 720 x 480 pixels) • Accessibility—how quickly stored video data can be retrieved and reviewed The surging popularity of digital video surveillance solutions stems from their ability to deliver dramatic advances in all three of these critical areas. Boosting the quantity and quality of video data demands far greater storage capacity than is available from legacy tape-based systems. Thus leading digital surveillance systems to rely on purpose-built surveillance hard disk drives (HDD), whose prodigious capacity eliminates a key bottleneck from these systems. Similarly, tape-based systems are limited to sequential data access, severely constraining the speed and ease with which data can be retrieved. HDD-based surveillance storage again provides the solution, its random access capabilities vastly accelerating the retrieval and review of vital video information. Simply put, HDDs are proving themselves a fundamental enabling technology of the digital surveillance revolution. 1 Source: IMS Research, The World Market for CCTV and Video Surveillance Equipment 2007 Edition, November 2007
  2. 2. Video Surveillance: The Migration to Disk-Based Storage Reaching the End of Tape Accessibility—Tape-based surveillance storage can only sequentially access a desired piece of Much like the home VCR market in the 1980s and video data. That is, a search that begins at point A 1990s, the video surveillance market has been on a tape and ends at point B (where the desired dominated by analog-based video capture and video footage resides) must traverse all of the recording of surveillance footage to traditional data in between those two points. This greatly tape-based systems. And just as the home video slows down access, particularly when the start/ market has quickly supplanted VHS tapes with stop points are at opposite ends of the tape. the superior image quality and reliability of digital DVDs, so too is the video surveillance market eschewing tape-based solutions in favor of digital systems utilizing HDD storage. Video Tape The liabilities of tape-based storage are numerous and interrelated, demanding users strike a Start Target delicate compromise to achieve acceptable Point Time Footage results. Furthermore, once found, the desired footage Recording Time—This is a function of both can suffer degraded image quality from repeated tape speed and tape length. Decreasing the tape reviewing. Because the tape is in actual physical speed increases the maximum recording time per contact with the tape head, frequently playing cartridge, but image quality can be significantly and rewinding the tape can gradually wear away degraded. Increasing the tape length allows more the magnetic coating that stores the video data. recording time but requires thinner tape in order Image degradation can also occur during storage to fit in a standard cartridge; thinner tape is more due to print-through, wherein magnetism from fragile, increasing the chance of tape stretching or adjacent tape layers bleeds through to imprint outright breakage. ghost images. Recording Quality—This is primarily a function The HDD Advantage of tape speed. Faster tape speed yields higher image quality, but cuts the maximum recording With the above points in mind, it should come as time per cartridge, thus requiring users to more no surprise that digital video surveillance systems frequently load/unload tapes throughout the day. utilizing hard disk drives are rapidly replacing Using thinner tape boosts maximum recording tape-based systems. Bringing unprecedented time but, as noted above, increases the chance of power to vital security applications, these disk- stretching and degraded image quality. based solutions enable a comprehensive range of benefits and capabilities. Huge Recording Capacity—Offering up Storage Capacity Image Quality to 1-TB capacity per disk drive, surveillance storage systems equipped with HDDs ensure unprecedented freedom to deploy a multitude of cameras for broad, comprehensive video Slower Faster surveillance coverage. Dozens, even hundreds, Tape Speed of video streams can be accommodated Multiplexing—Multiple video streams can be simultaneously, all without the need to periodically sent to a single recording device via the use of a remove/insert tape media. multiplexer. However, tape-based storage entails compromise because a single cartridge can’t simultaneously meet the needs of high-resolution 289 Days 32 Days streams (ideally recorded at higher tape speeds Surveillance Video Surveillance Video for maximum image quality) and low-resolution (640 x 480, 10 fps, JPEG) (720 x 480, 30 fps, MPEG-4) streams (preferably recorded at low tape speeds for maximum recording time). 2 1 TB Drive 1 TB Drive
  3. 3. Video Surveillance: The Migration to Disk-Based Storage Furthermore, this wealth of capacity pays Advent of Intelligent Video important dividends in the ability to archive video The value proposition of digital surveillance for extended periods. Archive periods can be systems equipped with hard disk drives becomes economically extended from thirty or sixty days to even more compelling when intelligent video months (even years), providing additional security applications are added to the picture. Taking protection as well as ensuring compliance with full advantage of the high-resolution, capacity- rigorous regulatory and legal requirements. intensive video streams that HDD storage Superior Image Quality—Eliminating analog effortlessly handles, intelligent video applications limitations (poor signal-to-noise ratio, saturation, will profoundly increase both the capabilities and tape stretch, etc.) that undermine recording cost-effectiveness of video surveillance systems. quality, HDD storage ensures consistently At its core, intelligent video reviews the superior image quality. And having banished exceptional detail found in high-resolution tape’s trade-off between recording speed/quality video streams and analyzes it to recognize and recording time/capacity, it also enables visual patterns. Perhaps the best-known use of multiplexed streams to be individually configured this technology is facial recognition; intelligent for optimum results. software analyzes the faces of persons in stored Even more importantly, the enormous capacity surveillance footage, comparing their features of disk-based storage enables users to specify to the faces of known suspects/criminals on more aggressive capture rates and resolution (for file. When a match is identified, the application example, 30 fps and 740 x 480 pixels) to maximize automatically notifies security personnel for image quality. Such settings can rapidly consume follow-up investigation. vast quantities of storage space, which an HDD- Of course, these applications review stored based system can readily supply. surveillance footage (review being too calculation- As a result, image quality need never be intensive for real-time processing) for other visual compromised because of limited storage patterns as well. For example, the application can capacity, a key consideration with today’s be configured to identify unusual behavior (for intelligent video applications (see below). example, a person running in an area where such activity is unusual), flag suspicious persons and Rapid Accessibility—Disk-based surveillance alert security staff. Or it can compare reference storage offers random access to any video data video images of a locked door to surveillance on the disk drive. This means that the read/write footage to check for signs of a break-in. head can go directly to the desired video footage, bypassing all of the data that lies between the The remarkable synergy between intelligent search’s starting point and its destination. video applications and digital video surveillance systems makes the benefits of disk-based surveillance storage even more compelling. Disk Drive That said, all disk-based storage is not the same. Surveillance has unique requirements that demand drives specifically engineered to Start Target meet those needs. Such drives offer compelling Point Instantaneous Footage advantages over conventional drives. This ensures vastly faster access to video footage Seagate® SV35 Series™ Drives: Purpose-Built than tape-based storage; furthermore, with for Surveillance no tapes to swap in and out, the surveillance system’s disk drives (and the video images they The Seagate SV35 Series hard disk drive is the contain) are always immediately available. first drive specifically engineered and optimized for digital video recording in security and And because the disk drive’s read/write head surveillance applications. As one would expect, does not physically contact the platter, video SV35 Series drives deliver prodigious capacity footage can be reviewed again and again without (up to 1 TB) to store massive amounts of digital image degradation. 3 video: 289 continuous days per camera (640 x
  4. 4. Video Surveillance: The Migration to Disk-Based Storage 480, 10 fps), 32 continuous days per camera (720 the capability to power down when not in use, x 480, 30 fps) recording 24 hours a day, 7 days a saving both power and enabling more efficient week. system cooling. But SV35 Series drives drives do more than just • Intelligent workload monitoring—SV35 deliver outstanding capacity; they also address Series drives utilize monitoring algorithms to the disk drive durability challenges inherent in sense specific workload profiles that can stress always-on surveillance environments. Given key systems and then take corrective action. the potentially critical nature of the security • Designed for 24x7 operations—SV35 Series data involved, the application-specific features drives can withstand the intense duty cycles employed in the SV35 Series drive to enhance common in digital video recording for security reliability take on even greater significance. and surveillance. As can be seen below, the SV35 Series family The enhanced functionality of SV35 Series drives of surveillance disk drives includes custom doesn’t end there. Video security drives are features not found in conventional desktop drives primarily used for streaming video, but they must to intelligently deal with heat management and also be capable of conventional data reads and power consumption: writes, used in the course of managing video databases and related applications. SV35 Series • Advanced power management features— drives support the ATA-7 command set, enabling SV35 Series drives require lower startup and their read/write profiles to be tuned to video- or operational current, enabling the design of low- data-specific, as appropriate. cost power supplies. The drives also include Summary: Desktop Drive vs. Seagate SV35 Series Drive Seagate® SV35 Series™ surveillance drive Conventional desktop drive Custom Drive Features Excellent; extensive power management features reduce heat, power use None; not designed to handle heat in rigorous power-on and workload environment Projected Reliability Excellent; workload monitoring protects drive under heavy use Unknown; not designed for use in always-on surveillance environment Overall Value Excellent; dedicated drive design comparable in price to traditional Poor; workload, heat issues negate lower initial purchase price desktop drives Conclusion Widespread adoption of digital surveillance Seagate is leading the surveillance storage systems is being driven both by heightened revolution with the SV35 Series family of disk security concerns and the desire for more drives, the industry’s first line of drives specifically powerful, cost-effective surveillance systems. built for the unique requirements of digital video Hard disk drive storage is the linchpin of digital surveillance systems. security solutions, delivering an unprecedented combination of capacity, speed and durability to enable a compelling new class of intelligent video applications. AMERICAS Seagate Technology LLC 920 Disc Drive, Scotts Valley, California 95066, United States, 831-438-6550 ASIA/PACIFIC Seagate Technology International Ltd. 7000 Ang Mo Kio Avenue 5, Singapore 569877, 65-6485-3888 UROPE, MIDDLE EAST AND AFRICA E Seagate Technology SAS 130–136, rue de Silly, 92773, Boulogne-Billancourt Cedex, France 33 1-4186 10 00 Copyright © 2008 Seagate Technology LLC. All rights reserved. Printed in USA. Seagate, Seagate Technology and the Wave logo are registered trademarks of Seagate Technology LLC in the United States and/or other countries. SV35 Series is either a trademark or registered trademark of Seagate Technology LLC or one of its affiliated companies in the United States and/or other countries. All other trademarks or registered trademarks are the property of their respective owners. When referring to hard drive capacity, one gigabyte, or GB, equals one billion bytes and one terabyte, or TB, equals one trillion bytes. Your computer’s operating system may use a different standard of measurement and report a lower capacity. In addition, some of the listed capacity is used for formatting and other functions, and thus will not be available for data storage. Quantitative usage examples for various applications are for illustrative purposes. Actual quantities will vary based on various factors, including file size, file format, features and application software. Seagate reserves the right to change, without notice, product offerings or specifications. TP563.2-0809US, September 2008