Why EX SDI cameras? digital, low latency, low bandwidth

Updated: Mar 19, 2020



EX SDI camera - Summary of benefits


1) EX SDI cameras make use of a signal that is digital, therefore

  • video quality level absolute (100%)

  • video signal is less prone to noise

  • video signal can be directly processed by an FPGA for image analysis, without ADC (analog to digital conversion) or other noise enhancing steps

2) EX SDI cameras have a video signal without (or hardly any) latency

3) EX SDI cameras have a video signal with lower bandwidth

  • allowing longer distances of signal transport if compared to HD SDI / 3G SDI /6G SDI

  • offering more flexibility in wiring


Industrial EX-SDI camera - Medical EX-SDI camera

skoopia offers more. Also operator productivity is fundamental in medical or industrial applications. Therefore, all skoopia EX SDI board cameras and skoopia EX SDI block cameras (often called EX SDI zoom blocks) support VISCA as a command protocol. Moreover, skoopia EX-SDI cameras have a very small form factor (e.g. 22mm x 26mm EX SDI camera 21C26S, see details below) making it very suitable to implement in space contained OEM camera products.


Finally, skoopia is well aware that a transfer from CVBS to EX SDI or even a transfer from regular SDI (HD SDI / 3G SDI / 6G SDI / 12G SDI) to EX SDI comes with questions from customers, adaptations and a legacy installed base. Therefore, all skoopia EX-SDI board cameras and all skoopia EX-SDI block cameras support CVBS and the regular SDI, minimizing the impact that comes with the transition.


skoopia ex sdi OEM cameras combine the advantages of ex sdi with the advantages of operator productivity and smooth transition from CVBS camera to EX SDI camera or from HD-SDI camera to EX-SDI camera.

EX SDI camera from skoopia

EX SDI cameras introduction

skoopia markets several video outputs for cameras. Although skoopia market indsutrial IP cameras and medical IP cameras and skoopia has a wide range of industrial IP cameras in her portfolio, IP cameras have a significant latency, making them unsuitable for user / operator / medical doctor / surgeon assisted operation.


Comparison between different industrial cameras or medical cameras, all making use of compression enlarging efficiencies, Clinton Electronic, primarily active in the security camera business has made a very good video footage of the benefits of EX SDI cameras if compared to AHD cameras*, TVI cameras or CVI cameras.


* skoopia markets AHD cameras for settings in which EX SDI is not suitable or EX SDI is too cumbersome to implement. Nice to see in the "third party" video that although AHD cameras provide a lower quality compared to EX SDI caemras, it clearly outperformes (HD) TVI cameras and (HD) CVI cameras.


So, an EX SDI camera provides - alike 3G-SDI or HD-SDI cameras- the best image quality using regular coax. But EX SDI camera video output travels over longer distances. So what is EX SDI?


EX-SDI cameras or EX SDI cameras (sometimes written with sometimes without hyphen) stands for Extended Serial Digital Interface cameras. EX SDI cameras can transmit up to 4K - UHD - 2160p resolution for compressed video over coaxial cable.


Who is behind EX SDI camera technology?

Digital signal processor (DSP) chips supporting EX-SDI are developed and marketed by the South Korean company Eyenix.


Eyenix is a fabless DSP chip developer focused on high end industrial, medical and security applications.

To reach the compression Eyenix uses a technique called VLC (Visulally Lossless Codec). While latency of EX-SDI and HD-SDI/3G-SDI/6G-SDI is identical, the bandwidth of EX-SDI is lower.

video resolution 1080p30 1080p60 1440p30 2160p30


regular SDI HD-SDI 3G-SDI 3G-SDI 6G-SDI

bandwidth SDI 1.5 GHz 3 GHz 3 GHz 6 GHz

EX-SDI version v1.0 v1.0 v2.1 v2.1

bandwidth EX-SDI 250 MHz 500 MHz 500 MHz 1.5 GHz

Compression factor 6 6 6 4

Standard coax cable used for HD-SDI transmission (1.5 GHz) could therefore be used transferring 2160p30 (4K) video, as the frequency of the EX-SDI video signal has an identical bandwidth.

Eyenix has reported that EX-SDI 3.0 will support two output versions, a video output mode with a visually lossless (2160p30 at 1.5 GHz) signal and a video output mode with limited band width, but having visual losses (2160p30 at 250 MHz) in the video signal.


Visually lossless EX-SDI camera

Compression of video or images always generates a loss. Also EX-SDI cameras show a measureable loss in the video signal. However, this loss cannot be detected by the human eye.


The signal to noise ratio of contemporary cameras (skoopia sources source the best in world sensors from Sony (Sony Starvis Exmor R or Sony Preius Exmor R). Sony sensors provide a signal to noise ratio of approximately 43 dB, significantly better then old CVBS industrial cameras (typically at 38 dB). While these visual differences can clearly be observed, the difference between an EX-SDI video signal and an HD-SDI or 3G-SDI video signal coming from the same OEM camera (e.g. the industrial camera skoopia 128C42X or the skoopia 21C26S) can not be seen.


The compressed of the EX-SDI still has a signal to noise ratio of 56 dB, well above the 43 dB provided by worlds best sensors.. Effectively, only the identical noise level can be seen, not the image quality difference.

4K EX SDI camera

skoopia believes that the adoption of EX SDI is still at its infancy. Industrial and medical applications will continuously look for higher resolutions and/or longer/easier cabling distances. EX-SDI will be a suitable alternative. Particularly that one can upgrade from existing HD-SDI infrastructure to 4K-SDI without altering the cabling without any visual impact on the video appears extremely beneficial.


Video signal     EX-SDI (MHz)    S/N ratio (dB)    Distance (m)      HD-SDI (MHz)    Distance (m)

1080p30                  250                      56                       300                       1500                   80

2160p30                1500                      56                         80                       6000                   n.a.

2160p30                  250                      38                       300                       6000                   n.a.


skoopia has released a blog on 4K EX-SDI camera for medical SDI applications, but also for industrial EX-SDI camera applications. Click here to read the blog. It's first medical 4K EX-SDI camera and industrial 4K EX-SDI camera has been released in December 2019.  


​EX SDI camera is digital.

EX SDI as a video output has the advantage of being digital. Although it has a higher bandwidth if compared with e.g. AHD cameras, the image quality is superior. Reasons are:

  • No video degradation over distance

  • Less susceptible to interference (electromagnetic noises)

The above two pictures show the impact of distance versus image quality. On the left you see the video quality gradually become worse over distance, which is very typical for any analog video transmission, such as video coming from AHD OEM cameras. On the right you see the video quality of a digital camera. Quality remains perfect up to the point that the signal cannot be transported, and the signal is lost. EX SDI board cameras or EX SDI block cameras will show such behavior (here 1000 foot, approximately 300 meter) implies that is is very likely a measurement made with an EX-SDI OEM camera, as HD-SDI or 3G SDI camera signals can typically not reach the described distances.


The above picture explains why analog video is more susceptible for noise, if compared to digital video. Whereas digital video is binary (0 and 1) in height and fixed in length of signal, the analogue video has different amplitudes as well as different length in time. Both make it more susceptible to noise, as can be seen in the pictures. Top is the signal without noise. Middle picture is the signal with noise. Last picture shows the difference between the original signal and the signal with noise. On the left is the analog signal. Ont he right is the digital signal.


Clinton Electronics, has made a great video to describe the benefits of Digital EX SDI cameras versus analog cameras (CVBS camera, AHD camera, TVI camera, CVI camera).



Back ground reading: SDI camera

SDI camera stands for Serial Digital Interface camera. At this very moment, SDI is vastly adopted in the medical and broadcast industry, and adoption in other industries is growing fast. 

SDI as video signal has several sizable advantages over other digital transmission techniques.

Key advantages of SDI:

  • Low latency (alike CVBS)

  • Superb image quality as it is uncompressed

  • Coaxial cabling

  • Plural options at the receiver side, SDI monitor, SDI grabber, SDI recorder 

  • Support of Up the Coax - A smart cabling solution allowing power as well as camera control signals to use the same wires as the video transmission.

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SDI has several frequencies providing different resolutions. Some resolutions have a specific name and are formally put into a standard by SMTPE, The Society of Motion Picture and TelevisionEngineers.