For years, HD resolution and single cable signal/power were IP camera advantages, with analog cameras limited to much lower resolution and requiring separate power and video cables. However, in new HD analog cameras, AHD, CVI, and TVI have made significant advances, with resolution similar to IP, single cable power up the coax, and more.
In this report, we examine AHD, CVI and TVI, including their latest generation advances, compared to IP cameras, including:
- HD analog variants: AHD, CVI, TVI
- Encoding / transmission differences between IP and HD analog
- Advantages and disadvantages of encoding in the camera
- Resolution differences between HD analog and IP
- Advanced features: I/O, audio, camera side motion, etc.
- Recorder compatibility
- Coax compatibility
- Power over Ethernet (PoE) vs. Power over Coax (PoC)
- Vendor support of HD analog
- Cost differences between analog and IP
2019 Updates: Power Over Coax, 8MP/4K Resolution, Broader Support
Though they were slow to arrive, long-promised features such as power over coax and 4K camera availability have been released as of 2019:
- Power Over Coax: Though power over coax is not universal, Hikvision offers 10-20 models of PoC TVI cameras (see our test of Hikvision PoC TVI). Dahua offers several models of PoC CVI cameras, though more limited than Hikvision. There are some available AHD PoC cameras, though none from larger AHD providers (Hanwha, Digital Watchdog).
- 4K/8MP HD Analog: 8MP HD analog models are common in 2019. Note that while they are marketed as 4K, they are not technically true 4K, as they do not support 30 FPS required by standards. See our test of Dahua/Hikvision 8MP CVI/TVI.
- Broader support: In 2019, many new generation HD analog DVRs and encoders support AHD, CVI, and TVI as well as SD analog on the same ports, effectively creating “universal” recorders. This allows for greater flexibility in camera selection and reduces vendor lock-in.
HD Analog Variants
There are three major HD analog variants:
- Analog High Definition (AHD)
- High Definition Composite Video Interface (HD-CVI)
- High Definition Transport Video Interface (HD-TVI)
All HD analog cameras support coaxial video transmission, typically to 500m of RG-59 cable and, at least a max resolution of 1080p, with new generations adding support of 3MP, 4MP, 5MP, and 4K.
Analog High Definition (AHD)
Analog High Definition (AHD) was developed by Korean chip manufacturer NextChip, originally specified with a max resolution of 720p, but increased to 4MP, 5MP, and 4K in later releases.
The most well known brands supporting AHD include Hanwha and Digital Watchdog. However, AHD is also favored for lower cost offerings from less established brands. For example, cameras may be found with prices of $10 or less, though typically from vendors with no brand and minimum support.
High Definition Composite Video Interface (HD-CVI)
HD-CVI (Composite Video Interface) was developed by Dahua and was originally exclusive to them. It has since been licensed to others, though non-Dahua CVI product remains rare.
The major sources for CVI product in North America are Dahua and their OEMs such as Honeywell or IC Realtime, which OEM various camera and recorder models, as well as a handful of lesser known brands.
Dahua originally kept CVI proprietary, not only blocking support for AHD and TVI, but also threatening to sue them. Then, in 2016, Dahua changed their position with their 3.0 release, opening up support for AHD and TVI on their HD analog recorders.
High Definition Transport Video Interface (HD-TVI)
Chip manufacturer Techpoint developed HD-TVI (Transport Video Interface), which has been adopted by several manufacturers, the largest of which is Hikvision, Dahua’s main direct competitor. Others, such as KT&C, CNB, Speco, and smaller manufacturers have adopted it, as well. Additionally, Hikvision has numerous brands OEMing them, and HD-TVI is increasingly becoming available from them.
TVI’s latest releases have added recorder support for AHD and CVI cameras as well as PoC, 5MP and 8MP/4K resolutions (all in 2017/2018).
Encoding/Transmission Differences
All surveillance is encoded and compressed (e.g., H.264 or H.265). The key difference between HD analog and IP is where compression is done.
In IP cameras, compression is performed inside the camera. In HD analog, compression is performed on the server side (e.g., recorder, encoder, video server, etc.).
This is a major driver in performance differences.
Advantages Of Encoding In the Camera
IP cameras have several advantages due to compressing things in the camera:
- Bandwidth is essentially ‘unlimited’. Because the video is compressed in the camera, the output can be 3MP, 5MP, 10MP, 20MP or more and can easily ‘fit’ inside standard networking infrastructure (e.g., 100Mb Ethernet).
- Advanced features can easily be added as the same computer that compresses the video, can compress audio, dewarp fisheye panoramics, support multiple imagers, perform video analytics, etc.
- No specialized hardware is needed on the receiving side. Since the video is compressed typically in standards-based H.264 (or H.265), all the VMS / client / recorder needs is open source software to decode / display. Connecting to the camera is driven by the IP camera manufacturer’s API or, increasingly, ONVIF. By contrast, when encoding on the server side, specialized hardware always needs to be provided, which limits backwards compatibility and recorder support.
Disadvantages Of Encoding In the Camera
IP camera cost increases since every camera requires the processing power / hardware to encode instead of just adding it to a single or a few recorders / encoders which then handle encoding for multiple cameras. This is one reason why HD analog cameras are generally notably less expensive than IP cameras.
Along with this increase in cost, since every IP camera is a computer, complexity is higher. With the benefits of cameras being a computer come the downsides of computers – increased complexity, potential for software incompatibilities, need for integration, etc. These issues are simply not present in analog (HD or SD) cameras.
Resolution Similar In IP And HD Analog
Historically, both HD analog and IP cameras regularly delivered Full HD 1080p resolution. This was a big jump from SD analog’s previous limitation of VGA / ~0.3 MP. However, 4K / 8.3MP IP cameras are now commonplace.
In 2019, “4K” CVI/TVI cameras are now available, though frame rate is limited to 15 in the vast majority of cases, so is not “true” 4K, which requires 30 FPS as per standards.
For now, IP has a lead in resolution at full frame rate, though increasingly only for niche applications that really need a single camera with very high resolution. Especially for indoor usage and homes / smaller business, 1080p HD is often enough, with 4MP growing fast.
Advanced Features: Advantage IP
IP has a large lead in advanced features, given that IP cameras are basically computers with cameras attached and can therefore include all sorts of advanced processing (audio, fisheye dewarping, support multiple imagers, on board video analytics, etc.).
AHD, CVI, and TVI all offer PTZ/OSD control up the coax. CVI and TVI offer some features of IP such as I/O and two-way audio, in theory, though model support for these features is rare.
Recorder Compatibility
IP cameras can be made compatible with any recorder or client by adding software, whether it is proprietary integration or the use of “standards” like ONVIF.
HD analog camera types require specialized receiver / encoding hardware which cannot simply be added to older analog DVRs. New recorders (or encoders) must be purchased along with cameras. Increasingly, AHD, CVI, and TVI recorders are able to mix and match inputs of NTSC / PAL analog with their own HD analog type.
HD analog types were historically not compatible with each other. For example, if you connected a TVI camera to an AHD or CVI only recorder, you will get no usable video (likewise, with the other way around).
Universal Receiver Support Now Common
While it has historically been an issue, HD analog compatibility has increased significantly as of 2019, with multiple manufacturers now offering “universal” DVRs or encoders which support AHD, CVI, and TVI, such as Axis’ HD analog encoders, Dahua’s “Penta-brid” recorders, or Digital Watchdog’s Compressor HD.
However, users should beware of limits on resolution, frame rate, and advanced feature support of some variants when using these recorders, as a manufacturer may support their preferred standard at full resolution/frame rate, but remove higher resolution support in others or eliminate up the coax control and other features.
Coax Compatibility: Advantage HD Analog
IP cameras require Ethernet over Coax (EoC) Shootout to run over legacy coax. These typically add $100 to $400 per camera.
All other camera types are designed to run over legacy installed coaxial cable, though the distance limitations claimed vary. CVI and TVI both claim “over 1,500′” using RG-59 (and with our tests validating that up to 1000′). In our tests, early TVI releases had some issues using long cable runs, but these have since been remedied in HD-TVI 2.0 chip releases.
PoE Vs. PoC
One of the big installation benefits of IP cameras has been Power over Ethernet (PoE). Instead of using one cable for video and another for power, a single cable can be used and power transformers can be eliminated.
HD analog manufacturers have been slow to introduce single cable power/video, but it is now shipping in some models. With Power over Coax (PoC), siamese cable can be replaced with RG59 alone, external power supplies can be dropped and some labor time can be reduced. Additionally, PoC offers longer distance power transmission than PoE, with 200-300m runs possible on RG59 coax vs. 100m using standard PoE/UTP.
As of 2019, Hikvision has released some models of Power over Coax (PoC) cameras and DVRs (see our test), with models becoming more common. Dahua has introduced some models in other regions, but none in North America.
Vendor Support
IP has massive vendor support, both in terms of number of manufacturers and range of form factors available.
HD analog variants have growing support, though limited by its relatively short availability.
- AHD has historically had the least vendor support, with only low cost or no name brands utilizing it. However, manufacturers such as Samsung and Digital Watchdog offer AHD product, as well.
- CVI has broad support amongst Dahua (the founder of CVI) and their OEMs (in North America, most notably Honeywell and Q-See).
- TVI is supported by a number of companies, but by far the largest is Hikvision (and their OEMs).
Western / Japanese Big Brands Not Supporting HD Analog
Most of the biggest brands in the world are not supporting HD analog. For example, Avigilon, Canon, Bosch, Panasonic, Pelco, Sony are all not supporting HD analog.
Notably, in 2019 Axis announced their first encoders supporting HD analog, making them practically the first of the Western / Japanese brands to do so.
However, Axis has not marketed these new encoders at all, introducing them without a press release, as they remain focused on IP.
The lack of Western support limits marketing efforts behind HD analog and, related, validation of the technology as many look to these larger manufacturers for cues about what technology to use.
By contrast, HD analog has been led by Chinese and Korean manufacturers, who are strongest in the low to mid tiers of the market and do not carry as much recognition with average buyers as the Western and Japanese brands.
Model Availability: Advantage IP
HD analog cameras supporting advanced features such as true multi-exposure WDR, super low light, etc., are less common than IP cameras with these features. Newer generation Dahua and Hikvision HD analog products increasingly support advanced features, but these are still less widespread than IP cameras.
On the other hand, many premium features and niche form factors are still far more widely available in IP than HD analog models as most vendors look at HD analog as primarily focused at the budget market where lower cost and less sophisticated options are expected.
Cost Comparison: Advantage HD Analog
HD analog has significant cost advantages over IP, both on the camera and recorder side. 30-50% lower cost for HD analog vs equivalent spec’d IP systems is commonplace.
IP camera costs are now moderately high, failing from extreme high prices in the 2000s and helped by lower cost Asian vendor expansion in the past few years. In 2019, a ‘cheap’ IP camera from a name brand bought though a local distributor runs in the $80 – $100 range.
AHD, CVI, and TVI cameras and recorders are extremely inexpensive, even compared to similar entry level IP cameras, with prices starting at ~$30 USD for 1080p cameras and recorders starting below $100.
Install Simplicity: Advantage HD Analog
Connecting cameras to recorders is more difficult with IP than any of the non analog versions. With IP, each camera needs an IP address, the network needs to be set up directly, the tech needs to know IP to connect the cameras, and the VMS/recorder must support them, either via direct driver or ONVIF.
Experienced IT surveillance professionals will not find this a major problem. However, many non IT and traditional low voltage techs will find HD analog’s “plug and play” installation much easier.
HD Analog Closing the Gap on IP, Still Lower End Though
Increasingly availability, better industry recognition and improving features (higher resolution, better compatibility) are helping drive HD analog adoption.
On the other hand, HD analog is still firmly focused / dominant in the low end of the market. The lack of camera options and the refusal of the biggest Western and Japanese brands to support HD analog all hold it back.
Finally, there will remain functional advantages for IP cameras for higher end applications indefinitely, as edge storage, on-board analytics, multi-imagers with a single output, etc. will continue to be IP only. Additionally, many larger applications have standardized on UTP cabling. While HD analog cameras can be used with added baluns, IP cameras remain a more natural / direct fit for such cabling architectures.
Article provided from IPVM.com