From the Product Manager's POV

• By Steve Surfaro
• Oct 02, 2007

New technologies are taking the world by storm. That means the security industry is in the midst of change and product rebirth. The same holds true for recording devices. DVRs are cost-effective, and NVRs are state-of-theart. Not sure which to choose? Read what Panasonic group manager Steve Surfaro has to say and then decide.

Q.Can a DVR, rather than an NVR, be the right choice for an IPbased system?

A.It would depend on the physical size and geographic scope of the system. Since surveillance cameras are cabled directly into DVRs, distance becomes an issue, because it is impractical to run hundreds of yards of cable and because image quality can degrade as the signal travels over distance. There also is a limit to the number of control inputs and outputs for interfacing and integrating to various systems and devices. When a DVR unit’s video inputs are full, another unit must be added, typically with groups of eight, 16 or 32 video input capacities. Still, for smaller applications, DVRs are a cost-effective way to record and archive video, and with today’s more advanced DVRs like the Panasonic WJRT416, it is possible to build a networked surveillance system with the ability to view real-time video over the Internet.

A DSL or cable modem connection will typically display 1 fps. When viewing remotely, the refresh rate is determined by the Internet connection speed. When viewing or playing back locally, the display is dependent on the unit’s frame rate.

Q.Knowing that there are different compression formats out there, what are the advantages of MPEG-4 compression, specifically?

A.MPEG-4 dramatically advances video compression, enabling the distribution of content from low bandwidths to high-definition quality across broadcast, broadband, wireless and packaged media. MPEG-4 uses object-oriented compression, meaning that individual objects within a scene are tracked separately and compressed. This object-based compression has the benefit, among other things, of enabling interactivity. MPEG-4’s goal is to attain a high image quality at a very low bit rate. Its efficiency and range in bit rate management has made it popular for most of today’s Internet and recording applications.

Most wireless applications are using MPEG-4 because of its flexibility. It is becoming the standard compression for security applications due to the balance of high compression and high-quality video. MPEG-4 also gives developers flexibility in managing bit stream data.

Until now, networks were at the mercy of the data they were moving, which often led to bottlenecks. With MPEG-4, video applications can adjust to network loads. These are the reasons we incorporated MPEG-4 recording in the WJ-RT416 DVR series.

Q.Many products are loaded with features today. How important are frame rate and resolution?

A.These are issues that relate directly to the ability to identify objects and individuals within recorded images, so they are crucial for security applications. Frame rate refers to the number of images, or frames, that can be recorded per second. The higher the frame rate, the smoother the picture in real time. Resolution refers to the clarity of the image. The higher the resolution, the sharper and clearer the picture. The WJRT416 DVR delivers 480 ips over 16 channels (30 ips per channel) with 704 x 240 pixels at full-field resolution, capturing critical details that lead to accurate identification.

Q.Liability has become a much bigger issue in recent years, and archived video surveillance images have accordingly become much more important. What is the best way to archive images?

A.There are several options for archiving video surveillance images, and the need should always determine the method. If the need is to create a file of individual events relating to a specific individual or incident, these images can be isolated and backed up to a CD or DVD. If the user needs to back up the entire surveillance file for long-term storage, the best option would probably be a removable hard drive. Backup to network storage and USB flash memory are other storage options to consider. The most typical need is simply to maintain an archive of all recorded video for a period of time, after which it may be written over. This system allows for extended archiving of video using MPEG- 4 compression and on-board storage from 500 GB to 3 TB, therefore it allows for extended archiving of video, and it is ideal for both standalone and systems-based platforms.

Q.People are always concerned with wanting more storage. What can users do to optimize storage on their DVRs?

A.A number of factors influence harddrive capacity on a DVR, beginning with the type of cameras being used to input surveillance video. High-resolution cameras produce high-resolution images, which require more storage space. If optimal image quality is not a primary concern for a given location, using a camera with lower resolution will help optimize the storage space available on the DVR. The same is true of field of view and the selected frame rate of the cameras—the more information being recorded, the more space is needed.

Using a DVR that permits scheduled recording for specific limited time frames helps save space on the hard disk. Similarly, video analytics that initiate recording only when motion or other advanced triggers—unattended luggage or loitering, for example—are detected will help further limit the quantity of video being recorded and stored. The compression format used by the DVR also can help save hard-drive storage space. Video data takes up an enormous amount of space on a hard drive, so information must be compressed to reduce the size of the files and make it feasible to record and store large amounts of video data. The WJ-RT416 uses MPEG-4 compression, a growing standard for surveillance video.

Q.Today, consumers want information instantaneously. What are some of the advantages of real-time recording?

A.Real-time recording on DVRs is considered to be approximately 30 fps. Capturing critical event details in real time substantially enhances security because it helps to ensure accurate identification. The frames per second relate to how many images the DVR will record in one second. To calculate the frames per second per camera, take the total frames per second in the system and divide it by the number of video inputs. For example, a 60 fps DVR with four video inputs would result in about 15 fps per camera. Video surveillance technology has reached the point now where real-time recording can be cost-effective.

Q.Are there feasible hybrid configurations combining DVRs and NVRs for users that are in the IP transition phase?

A.Many users with legacy analog systems would like to introduce networked functionality while expanding or updating their systems. Using a combination of DVRs and NVRs integrated together via software can produce a seamless solution.