[科技新知] ccHDtv study

What is ccHDtv?

Closed Circuit HD TV (ccHDtv) is a newly developed solution for transmitting full HD digital video in a surveillance system. The core concept of ccHDtv is to deliver high definition video using digital TV (DTV) transmission. With ccHDtv, high definition digital video can be transmitted easily over coaxial cables, twisted pairs, or simply over the air. Multiple 1080p30 and 1080p60 video streams can be easily transmitted using ccHDtv over a single 3C2V/RG59 cable up to a length of 500 meters without any repeater.

In the world of analog TV, The composite video baseband signal (CVBS) is the most commonly used signal format. Its popularity, ease of use, and robustness have made it an integral part of our lives. CVBS is in fact a de facto signal standard for analog video surveillance systems. As we bid farewell to analog TV with worldwide analog switch-off (ASO) and move on to the age of digital TV, digital technologies, such as DVB-T, ISDB-T, and ATSC, became popular and indispensable much like CVBS in the analog age. ccHDtv leverages the extremely robust AV transmission capability of DTV to easily and seamlessly upgrade an analog cctv surveillance system to digital full HD. It is expected ccHDtv to become a de facto standard for digital video surveillance systems in the future.

ccHDtv is a novel technique pioneered by ITE Tech. Inc., ITE has devoted much resource into the development and promotion of ccHDtv solutions. ITE has developed key enabling products, reference system designs, and applications for ccHDtv . These products and applications enable seamless and friendly transition of video surveillance systems from analog to digital, be it all-new digital installations or upgrades from existing analog installations.

Core Technology: COFDM Transmitter / Receiver

More information on wiki: http://en.wikipedia.org/wiki/Orthogonal_frequency-division_multiplexing

Features of ccHDtv

• Reuse existing coaxial cable deployment without any upgrade for cables or connecters.
• Same system planning, deployment and debugging processes as used in traditional CCTV.
• Any iDTV set with DVB-T feature is able to receive ccHDtv signal without an HD DVR.
• Return channels are supported
  • Full duplex communication
  • HD DVR is able to support PTZ control, camera configuration, I/O settings, return audio and remote firmware update.
• Eavesdropping Prevention
  • Support encrypted signals in case of privacy consideration, so only authorized HD DVR can receive and
    decode it.
• No frame drops and real-time delivery
• Quasi-zero latency and quasi-real time preview for 9x, 16x, 32x...
• Long distance transmission
  • 3c2v/RG-59 up to 500M+ w/o repeater
  • 5c2v/RG-6 up to 1000M+ w/o repeater
  • Digital repeater for infinite extender
• High capacity/bandwidth
  • Multiple full HD camera video streams are able to be transmitted over a single coaxial cable.

ccHDtv Full HD Surveillance System

Devices in ccHDtv

Star Topology Deployment

• Exactly the same deployment as the traditional CCTV system
• The coaxial cable and connecter are the same. Actually, the cable medium requirement for DTV CAM is much less than analog cameras

Bus Topology Deployment

• Similar to cable TV deployment (multiple DTV CAM’s running on a single cable)
• Using same coaxial cables, connecters, mixers and amplifiers.
• ccHDtv is very robust and it’s not sensitive to cable network quality variation.
• Ring or multi-path connection is allowed in ccHDtv cable network which enables failure safe feature.

Ring Topology Deployment – Failure-Safe (Redundant) Cable Deployment

• Ring and multi-path connection are allowed in ccHDtv cable network which enables failure-safe (redundancy) feature
• Worst Recover time < 500ms

The above content is from ccHDtv alliance website.

http://www.cchdtv.com.tw/en/intro.php

More FAQ: http://www.cchdtv.com.tw/en/faq/index.php

Specification check points:

• Full duplex communication is supported.(two-way audio and control)
• Multiple stream is support. The max data rate per channel is 32Mbps.
• Wireless transmission is support.(depends on how you understand the regulations. so far ccHDtv suggest not to do so)
• Power on cable is supported. (Both AC/DC power)
• Crypto is support.

Pros compare to HDcctv

• The media is compressed. That means the ccHDtv could have much longer distance than HDcctv.
• ccHDtv supports bus, star topology. The installation is much easier than HDcctv. Besides, the cable cost is also much lower.
• ccHDtv support multiple stream transmission but HDcctv could not.
• ccHDtv support crypto but HDcctv is hard to support.
• ccHDtv use the television standard, the back-end support is much better than HDcctv.

Cons compare to HDcctv.

• None. Maybe the media is compressed.

Pros compare to IP camera

• Ethernet network bandwidth is very limited, and even worse when there are multiple IP CAM’s in the network. To save network bandwidth, IP CAM’s video is encoded with a lower bit rate or less frame rate. Beside, there are frequent frame drops due to overloading bus traffic.
• Each DTV CAM has its own proprietary data channel (up to 32 Mbps), and the guarantee of no frame drop. DTV CAM’s video can be encoded with a higher bit rate and higher frame rate. So the video quality is almost quasi-equivalent to lossless compression mechanism.
• The latency is much stable than IP. What IP can define is the best case.

Cons compare to IP camera

• Theoretically, more than 120 DTV CAMs. Practically, 32~48 cameras are recommended to minimize the adjacent channel (ACI), 2x and 3x inference. That means this solution is much suitable for small/middle projects. However, it could still co-work with IP network by gateway.

The topology show case in the Secutech booth

To make the conclusion:

• We could not see the large replace from original infrastructure to IP system. Only new and big system definitely implement IP system.
• ccHDtv create a much simpler way for traditional VGA system upgrade to HD system.
• ccHDtv can co-existence with IP system.
• IP's NVR system can leverage to support DTV camera. That means, DTV camera is almost an IP camera except the interface.
• ccHDtv use the TV standard and technical. It's robust.

So, in my point of view. This is dangerous to IP camera and it can much slow down the replacement from IP camera.