HD-SDI: The Hidden HD Technology
While discussion regarding high definition surveillance video has overwhelmingly centered around IP connectivity, there is an alternative. HDcctv, an HD-SDI-based open industrial standard for transmitting uncompressed digital video over point-to-point coax links, offers advantages depending on the application.
If you are a science fiction fan you may remember the Esper photo scene in the classic movie “Blade Runner.” Retired detective Rick Deckard (Harrison Ford) uses a special 3D enhancement machine to enlarge at many angles a high resolution photo in order to find an important yet hidden piece of evidence. This has always been a favorite movie of mine and makes me think perhaps someday security video will perform in a similar manner.
What does this sci-fi movie have to do with today’s CCTV systems? The answer is high quality, high resolution images. Once you have that, breakthroughs like digital, software-based pan/tilt/zoom (p/t/z), video analytics and facial recognition become realities.
While not yet as far into the future as in “Blade Runner,” we have made one important stride — video and images are now considerably higher in resolution than just a few years ago. Your customers should be happier. This month, we explore a high definition CCTV technology called HD-SDI (high definition serial digital interface) that has been in use for some time internationally and right under your nose here in the United States.
The application of HD-SDI video cameras and recorders can also be a great way for a security dealer to go back to existing CCTV customers and offer cool technical enhancements they would be crazy to refuse. In many instances the existing video coaxial cable infrastructure may be utilized, thereby making for a reasonably priced retrofit of new HD technology. Read on to learn more and see what some of the experts have to say about HD-SDI and HDcctv.
Keeping Existing Coax Among Perks
What is the lure of HD-SDI video? How would you like to provide 720p and 1,080p high def video over existing CCTV coax? If you know what to look out for this can be a distinct possibility. However, as we have learned in the past, any technology needs to be understood and careful application considerations made.
Jeff Silverman is a senior sales manager for Santa Clara, Calif.-based manufacturer Calsys Inc., which has been internationally active for years in HD-SDI. I asked him the following questions:
What are five major advantages of HD-SDI technology?
- No installation training required. It installs just like analog. All installers already know how to install it.
- No lag time or frame rate interruptions. No packetization at camera end. HD-SDI transmits uncompressed 1,080p digital signal. DVR compresses it into H.264.
- Keep the coax in place; no need to replace the wire.
- All brands interconnect with each other. Only one blend of HD-SDI is used, so all cameras and DVRs connect with each other.
- It’s a closed system. If the company’s network goes down, the HD-SDI DVRs and cameras continue to function.
What are some possible downside issues?
- The cost of HD-SDI and IP are about the same, so some integrators looking for a difference will not see much.
- Up until this year, there wasn’t enough variety of choices for cameras and DVRs. More models are coming out. Calsys is coming out with a 16-channel 1,080p and three hybrid models; 12/16/20 channels.
- There isn’t enough mention of HD- SDI technology in the security trades.
- Right now, nothing about the HD-SDI has been changed from what the broadcasting industry is using. Later this year, there will be changes. The HDcctv Alliance has more than 70 manufacturers working together to make changes to the HD-SDI, creating a CCTV version of it.
What must techs know to implement this technology?
If techs know how to install an analog system, then they already know how to install HD-SDI. HD-SDI also goes over fiber, so if they are going to use fiber, they would need to know how to do that as well.”
Why has there not been a lot of attention given to HD-SDI?
Most of the CCTV industry’s attention has been on IP, which is about 15% of installations. HD-SDI could have a faster acceptance if installers knew that they could keep the coax in place and not have to deal with setting up networks, routers and bandwidth issues. These are nonissues with HD-SDI. Also, HD-SDI has been around longer than IP and is used throughout the world in the broadcasting industry. Any sports or news program transmitted in HD uses 1,080p.
What are some misperceptions about HD-SDI?
How can a DVR record uncompressed video? It doesn’t. The DVR compresses it into H.264 for recording or streaming over a network or the Internet. It’s an intermediate solution until everyone goes IP. HD-SDI is part of the IP movement. HD-SDI transmits over secured coax or fiber and once it hits the DVR or encoder, it’s IP after that.
HDcctv Alliance Pushes Standard
The HDcctv Alliance is a nonprofit industry association that develops, manages and promulgates the technical interface specification for high-definition CCTV. The HDcctv standard adds security-specific capabilities and 100% multivendor interoperability to standards adopted by the broadcast industry for digital serial transmission of uncompressed HDTV signals over coax. The Alliance promotes adoption of HDcctv-compliant products and provides education throughout the surveillance equipment industry.
“The Alliance has introduced HDcctv 1.0, a simplified variant of HD-SDI 292M developed under license from SMPTE,” HDcctv Alliance Chairman and Executive Director Todd Rockoff, holder of a chip technology Ph.D. from Carnegie Mellon University, told me. “We are enhancing the standard with HDcctv 2.0 to include bidirectional communication with audio and 75Mbps down-cable data, HDcctv XR [eXtended Range] for more than double the transmission distance, and HDcctv CX [Cat-X] for native transmission over Cat-5e and -6 infrastructure.”
Rockoff says the organization expects to eventually add provisions for higher definition video such as 1,440p, 2k, 3k and 4k, which approaches 20 million pixels per image. “So there is a lot of headroom in the standard,” he says.
Ensure Lines Are Up to the Task
Let’s wrap up with a word of advice about the practical application of HD-SDI equipment, especially on existing RG-59 coax. Don’t be too quick to promise plug-and-play installations on existing older cable. The cable and BNC termination must be of a good quality. I would suggest you make your customers aware that existing cable needs to be tested. You may want to check out one of my favorite coax tester lines from ByteBrothers.
Bob Dolph has served in various technical management and advisory positions in the security industry for 30+ years. To share tips and installation questions, E-mail Bob at email@example.com. Check out his Tech Shack blog at www.securitysales.com/blog.
Tech Talk Tool Tip
In keeping with this month’s HD-SDI theme, I would like to introduce the recently released HD-SDI Balun from Mount Royal, Quebec, Canada-based MuxLab (muxlab.com). The device (Part #500701) allows one HD-SDI signal to be transmitted up to 150 feet via Cat-5e cable at HD resolution (720p, 1,080i) in a point-to-point configuration.
The HD-SDI Balun supports transmission of up to 2.97/3Gbps uncompressed, unencrypted digital video (optionally including embedded audio and/or time code) within television facilities and between professional video equipment.
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