As law enforcement equipment is used in critical missions, it must be rugged, capable, easy to use and based on proven technologies. These days, it must also feature open standards, along with technology that is cost-effective and flexible enough to allow users to future-proof their investment. The MPEG-4 technology that is now becoming ubiquitous to this type of gear brings a new level of capability to digital video downlinks, including improved delivery of critical, time-sensitive and actionable data to police officers, firefighters and emergency medical teams on the ground. Before you make an investment in new downlinks and receive sites, however, consider both the technology trends and your installed legacy MPEG-2 video systems.
The MPEG-4 advantage
Both MPEG-2 and MPEG-4 video compression standards are used for the same applications: video from helicopters, drop cameras or surveillance robots. The video is compressed in an encoder before it is transmitted or stored and decompressed in a decoder for playback.
The majority of legacy installed video downlink systems going back at least five years use MPEG-2 video compression. The quality of MPEG-2 video is quite good, but the format has a lot of limitations, especially for such in-demand applications as one-to-many multicasting, streaming of videos to phones, laptops and other types of end-user equipment, and automatic ingestion into video archiving systems.
Over the last several years, more law enforcement agencies have been requesting the higher-quality video that comes with high definition. It is a standard requirement for crowd surveillance at major events as the G20 summits and conventions, as well as for search-and-rescue operations. But HD video contains about four times as much information as standard definition. While MPEG-2 has low data rates with SD video, the HD data rates are much higher. Using MPEG-2 for HD video will invariably reduce the range of your video downlink system’s transmission.
For storage and archiving, MPEG-4 files take up less memory compared to MPEG-2. Additionally, most of today’s archiving tools and disc systems use MPEG-4 to natively ingest MPEG-4 compressed video and audio, saving you from needing to buy additional equipment to transcode MPEG-2 video.
H.264 is the next-generation video compression technology in the MPEG-4 standard. MPEG-4 H.264 delivers incredible video quality at data rates one-fourth to one-half the size of previous video formats. Better video at a lower bit rate translates into less storage required as well, providing additional savings.
In addition to its efficiency and better image quality, another important advantage of MPEG-4 H.264 video is the reliability of the video stream. Rather than breaking down into distinct blocks and jagged objects as seen in MPEG-2 video, the video is consistently crisp and clear. It also degrades gradually, softening an image without losing the detail critical to many situational-awareness scenarios.
The importance of open standards and interoperability
The success of law enforcement response operations often depends on the ability to receive crisp, detailed video information in real time and exchange it in one-to-many dispatches. This is so other units, agencies and responders are aware of the situation, can coordinate their response operations and prepare to assist as needed. In the past several years, interoperability, including that of video downlink systems has become a cornerstone requirement for the Department of Homeland Security, state law enforcement agencies and fire departments.
To ensure interoperability and share information with other jurisdictions and disciplines in a cost-effective and future-proof way, law enforcement agencies need to take into account the standards of the legacy equipment in state and local partners’ helicopter downlinks and receive sites. One of the major benefits of MPEG-4 is that it is an open standard that has been adopted by organizations across the globe. Many products and devices now support MPEG-4.
The MPEG-4 compression algorithm has been developed, among other things, to optimize video streaming on the Internet. MPEG-4 H.264 is designed as a simple and straightforward video coding application, with enhanced compression performance. It was also developed to provide a “network-friendly” video representation. MPEG-4 provides DVD-quality video, but uses a lower bit rate. This makes it feasible to transmit digitized video streams in LAN, and also in WAN, in critical situations, where bandwidth is vital and hard to guarantee.
MPEG-4 H.264 is on its way to becoming the next standard format of convergence in the digital video industry, regardless of the video playback platform. Major Internet players such as Google/YouTube, Adobe and Apple are all backing this cross-platform format. This should give law enforcement agencies the comfort and confidence of knowing that they will be able to transmit, distribute and play back video on a variety of end-user devices, as the application evolves. It also ensures they will not be locked into a single source of proprietary vendors and technologies.
Having the ability to “see” in poor conditions is an important aspect for most law enforcement applications. Operating in the dark, with visibility reduced by smoke or sand storms, in highly populated areas and similar conditions, are common scenarios for today’s search-and-rescue and other law enforcement operations. Advancements in camera technology must be balanced with advancements in the transport mechanism (i.e., the data link) to be able to supply increasingly high-resolution video content to the decision makers who may be located in a mobile command center on the ground, or possibly across the world. Improved picture quality is useless if it never reaches those that require this information to make wise decisions.
Efficient use of bandwidth
Why is bandwidth important? Besides video, users also want to include metadata and information from other sensors, such as infrared sensors, chemical/hazmat/nuclear-radiation detectors and GPS devices, among others. This information must be made available immediately to decision makers in multiple locations—squad cars, emergency response centers and firefighters. Video compression is the key to reducing the size of the signal to be transmitted. The application of the MPEG-4 H.264 standard to digital video microwave environments has greatly improved the efficient use of the crowded bandwidth. With the improved coding efficiency offered by MPEG4 over MPEG-2, public service organizations are able to deliver broadcast-quality video signals where previously there was not enough bandwidth for the higher data-rate requirements of MPEG-2. With the lower bit rate, the transmission becomes more reliable not only over the air, but on wired backbone networks and the Internet as well.
By using the more efficient MPEG-4 encoding, law enforcement agencies can reduce the bit rate substantially, while maintaining the same level of quality and significantly increasing the number of video recipients without the need for additional network backbone capital expenditure (CAPEX).
Future-proofing your system investment
Probably the most daunting challenge facing law enforcement agencies today is making investments in technologies, equipment and infrastructure upgrades that enable them to better manage and maximize the value and the full potential of their existing assets and infrastructure, while future-proofing these investments for tomorrow’s applications.
The fact that MPEG-4 performance upgrades can be performed (on some encoder models) purely through software is a great asset, because ongoing performance improvements of your systems can be done with no downtime through field upgrades, without disruption to the daily system operations. The CAPEX benefits of investing in hardware that can support such upgrades are clear.
Above all, it’s important to invest in video systems that support both legacy MPEG-2 and MPEG-4 standards. Either your own, or the legacy equipment in other jurisdictions, will inevitably include MPEG-2 systems. Your receive sites need to be able to receive MPEG-2 video, and you may be required to provide your video downlink to support operations outside your state. Today’s advanced aircraft transmitters feature MPEG-2 and MPEG-4 encoding, BCRYPT AES encryption, and COFDM modulation. The ability of your systems to support both MPEG-2 and MPEG-4 systems is a critical feature, as it protects your earlier capital investment while enabling you to take advantage of the newest MPEG-4 encoding.
Top performance is akin to safety
Local performance of homeland security operations is vital to the public interest. Maintaining effective local cooperation across policy sectors is necessary to create resilience in the face of terrorist attacks and natural disasters. Communications interoperability is vital to achieving community resilience during and after a natural disaster or terrorist attack. Moreover, achieving high performance on interoperability can inform how to secure other sectors, such as critical infrastructure, given similar political and economic constraints.
The importance of the MPEG-4 family of audio and video coding standards cannot be underestimated. Not only is it extremely successful in its own right as a cutting-edge technology, but it has also proved to be a powerful enabler for the new generation of content delivery platforms. MPEG-4 video compression saves valuable resources and enables law enforcement units to capture and deliver high-quality video while effectively managing bandwidth consumption.
