Specifications
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The SDI standard was developed for the broadcast industry by the SMPTE (Society of Motion Picture and Television
Engineers). The SDI standard denes the serial digital transmission of uncompressed video data. Initially, it was
developed as a digital replacement for analogue television and cinematic applications and has been used for many
years. It has now been adopted by the security industry for the transmission of 2 megapixel, full HD video.
Although the SDI standard is not restricted to a specic cabling method, the broadcast industry predominantly uses
coaxial cabling. Conveniently, this makes SDI even more applicable to the security industry.
SDI has many advantages over existing PAL or NTSC analogue technologies. SDI technology uses a digital si gnal
throughout the entire system. By comparison, analogue systems require the digital camera signal to be conver ted
to analogue for transmission and converted back to digital for the monitor to process. At every conversion, errors in
colour, accuracy and de-interlacing (if progressive scan is not used) occur, reducing image quality.
An analogue signal comprises amplitude, frequency and modulation data. After transmission, this data must be decoded
to produce an image. HD-SDI is a digital signal comprising only “1” and “0” data.
Like IP tech nology, a digital signal of this type is either transmitted correctly, or not at all. No data corruption or image
degradation can occur. HD-SDI and analogue transmission distances are similar. However, HD-SDI can transmit
signicantly more data as uncompressed HD video.
HD-SDI is a simple plug & play solution.
HD-SDI technology combines the best of CCTV and IP surveillance
HD-SDI video is transmitted at 1080p (progressive scan), 2 megapixel resolution of 1980 x 1080 pixels with a data rate of up
to 1.485 gigabits per second. This is considerably higher than analogue-based D1 resolution, which is 720 x 576 pixels and
IP-based, 1.3 megapixels resolution which is 1280 x 1024 pixels.
All cameras within an HD-SDI system are connected directly to the DVR. Even when transmitting uncompressed,
2 megapixel resolution video, in real-time (25 / 30 fps) there is no transmission delay between the camera and the monitor.
All cameras within the system can be recorded at their full HD, uncompressed rate, simultaneously. IP systems, by
comparison, can have transmission delays resulting in blocking and image artifacts. This is due to network bandwidth
limitations and will even occur in IP systems when a dedicated security network is used and multiple cameras are
attempting to transmit at once.
Megapixel video
HD-SDI takes video surveillance to a whole new level. It combines a higher image quality than IP,with the installation
and support simplicity of analogue.
2 Megapixel 16:9 HD-SDI Camera 400.000 Pixel 4:3 Analogue Camera
HD-SDI technology