What is SDI?

SDI (Serial Digital Interface) is a family of digital video interfaces first standardized in 1989 by SMPTE (Society of Motion Picture and Television Engineers), which sought to bring order, interoperability and consistency to the emerging world of digital video from previous analog standards.

SDI Advantages

SDI offers a range of advantages over competing interfaces for the successful transmission of professional video and audio, which has ensured its longevity as a standard to this day. Physically, many will associate SDI with the BNC locking connector, but the interface transcends the connector itself and lends itself to transmission over Fiber and IP networks as well. Here are some of the advantages that have ensured its success over the years:

  • Latency free imagery

    SDI signals are transported in latency-free and uncompressed digital signals over coaxial cables and offer crystal-clear imagery.

  • Scalability

    As resolution, frame rates and deep color offerings have expanded from the camera down the chain of production, post and delivery, SDI has continuously evolved to meet increasing bandwidth needs.

    Deeper color-space HD and progressive imagery led to the use of two SDI cables in-sync, described as Dual-Link, to achieve the needed bandwidth; testimony to SDI’s continual evolution when faced with new demands. For many 4K/UltraHD workflows today, up to 4x 3G-SDI connections can be utilized to carry and create a full 4K/UltraHD image; 12G-SDI simplifies that with transmission of the full 4K signal across a single 12G-SDI cable.

    SDI interfaces are numerous but for the sake of simplicity can be divided into the following bandwidth categories for coax use:

    • Standard Definition SD-SDI (270 Mbps, ST 259)
    • HD standard HD-SDI (1.483 Gbps, ST 292)
    • 3G-SDI (2.97 Gbps, ST 424)
    • 6G-SDI (5.94 Gbps, ST 2081)
    • 12G-SDI (11.88 Gbps, ST 2082)
  • Connectivity

    Traditional BNC connectors offer a rugged locking mechanism that offers security on set and in the studio, guarding against accidental uncoupling.

  • Length

    HDMI cables can only run up to about 30 feet before they require some type of amplifier or repeater, reflecting their original intention as a consumer interface. SDI in contrast can, depending on bandwidth, run to lengths of 300 meters before needing assistance. By connecting a SDI over Coaxial cable to an appropriate Optical Fiber converter like AJA’s range of 3G-SDI and 12G FiDOs, the signal can be further transmitted or received up to 10km from the source.

  • Security

    SDI over Coaxial Cable has functioned as a point-to-point transmission system which helps ensure security as it cannot be distributed further until deliberately connected to a DA (Distribution Amplifier) or a Router.

  • SMPTE TimeCode

    SDI supports Time Code, which gives every frame of video its own unique identifying number. This makes frame-accurate digital editing possible, and enables the association of other data to make audio and video even more focused, accurate, and repeatable. It can be used to synchronize music and is often used to automate lighting, pyrotechnics, video, and other effects in live concert production. HDMI does not support Time Code.

  • ANC Data

    SDI offers the ability to not only carry Video but Ancillary data (commonly abbreviated as ANC data) as well. In the context of television systems, ANC refers to a means which by non-video information (such as audio, other forms of essence, and metadata) may be embedded within the serial digital interface.

    Ancillary data packets are commonly divided into two types, depending on where they are located—specific packet types are often constrained to be in one location or another.

    • Ancillary packets located in the horizontal blanking region regardless of line, are known as horizontal ancillary data, or HANC. HANC is commonly used for higher-bandwidth data, and/or for things that need to be synchronized to a particular line; common items stored in HANC are VPID (Video Payload ID) and embedded audio.
    • Ancillary packets located in the vertical blanking region, are known as vertical ancillary data, or VANC. VANC is commonly used for low-bandwidth data, or for things that only need be updated on a per-field or per-frame rate. Closed caption data is generally stored as VANC.
  • Cost

    HD-capable SDI uses standard coax cable (RG-6) which is generally cheaper to produce than HDMI per foot or meter.

SDI Historically

1.5Gbps HD-SDI routing began to appear to support digital television ATSC HD OTA (over-the-air) transmission in North America. Digital television kicked off in the United States in 1996, so 1.5Gbps HD-SDI routing was a response to a serious need for improved conveyance of uncompressed digital video.

Less than half a decade later, the television industry started to replace the 1080i signal in some acquisition, production, and contribution environments with the higher frame rate and progressive nature of 1080p50/60 fps which required 1.5 Gbps HD-SDI bandwidth to be doubled, either through Dual-Link (using two SDI cables in tandem), or by jumping to the new standard of 3G-SDI with its doubled bandwidth over a single cable.

Today its common to find 3G-SDI infrastructure in a range of facilities, mobile broadcast trucks and live event environments. With the advent of 4K/UltraHD and high frame rate workflows like 60p and above, the pressure is on to move to a higher bandwidth offering.

What is 12G-SDI and Why Does it Matter?

As camera and routing technology continues to advance, broadcast and digital cinema grade SDI standards for resolution, frame rate, and color depth have been implemented to handle the increasing bandwidth of uncompressed video signals through the production and post chains.

Many smaller local television stations in the United States and Europe today are still using SDI (1.5G) systems, while the majority of production environments utilize 3G-SDI for HD pipelines and a combination of 3G-SDI cables to handle 4K/UltraHD workflows. Moving forward, many will need to upgrade their bandwidth in due course to handle cameras with 6G-SDI outputs, not to mention the 12G-SDI workflows now demanded by newer cameras like the Venice, recently announced by Sony.

The good news is that 12G-SDI is fully backwards compatible, simplifies cabling and with the correct tools, you can move your current infrastructure forward smoothly and simply. AJA is here to help ease the transition.

12G-SDI Advantages

12G-SDI offers multiple advantages. As a family of video interfaces standardized by SMPTE, SDI and their related interfaces offer nominal data rates when used for transmission of uncompressed, unencrypted digital video signals within television facilities.

12G-SDI offers eight times the bandwidth of normal HD-SDI and offers the simplicity of single cable connectivity. 12G-SDI has the ability to handle high frame rate and deep color 4K/UltraHD signals over a single cable, including up to 100/120fps. This has major benefits for live events, broadcast studios, on set and live venues when it comes to cable complexity, weight, and troubleshooting with far fewer points of potential failure in the signal chain. 12G-SDI over optical fiber further increases the distance that 12G can travel, up to 10km.

Advances in 12G-SDI

To learn more about the history and benefits of 12G-SDI, download the informative PDF below.

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AJA 12G Solutions

With broadcast technology constantly evolving, AJA is uniquely situated to provide future-proof technology for broadcast, production, post, ProAV, and developer partners in the video industry. AJA now supports 12G-SDI with solutions for editing, transmission over fiber, routing and Mini-Converters to Mux/Demux and distribute 12G-SDI where ever needed. AJA’s 12G-SDI solutions are all data agnostic, so they will continue to function as facilities migrate to HDR workflows and beyond.

Whether you are a high-profile media company, post-production house, mobile truck operator, or cinematographer, the reliability, flexibility and performance of AJA technology is incomparable. 

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Streaming: BRIDGE LIVE

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BRIDGE LIVE is a turnkey solution built for critical streaming applications with high performance 12G-SDI video encoding/decoding, stream-based transcoding, flexible I/O, comprehensive metadata support, closed caption support and a compact 1RU form factor with redundant power supplies.

Designed with the ability to support both low-latency and high-quality workflows across a range of codecs, containers and protocols, BRIDGE LIVE enables numerous use cases; Multi-input live streaming to platforms such as YouTube, Facebook or Twitch, providing high quality reference video for remote collaboration in production and post, backhauling remote live SDI video sources to the media production facility, SDI to MPEG-TS conversions for Telcos/IPTV/Cable networks, through to encoding for content distribution with ABR ladder profiles or hand-off for OTT packaging; all supported via public internet.

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Playback and Recording: Ki Pro Ultra 12G

Ki Pro Ultra 12G

Ki Pro Ultra 12G is a multi-channel Apple ProRes® recorder offering up to 4-Channels of simultaneous HD recording, or in Single-Channel mode, a 4K/UltraHD/2K/HD Apple ProRes or Avid DNxHR® recorder and player. Avid DNxHD® MXF is also supported up to HD formats in Single-Channel mode.

Ki Pro Ultra 12G offers 12G-SDI single cable simplicity for large rasters andHDMI 2.0 digital video connectivity with HDR support for recording and playback plus a wealth of analog and digital audio connectivity answers any project’s demand for efficient, powerful and flexible workflows. For distance and remote needs, Fiber SFP+ options are available.

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Mini-Converters: 12GDA, 12GM, Hi5-12G, HA5-12G, 12G-AM, 12G-AMA


12G-SDI to/from SDI Muxer/DeMuxer

12GM is a compact SDI transport converter that enables 12G-SDI to Quad-link 3G-SDI and Quad-link 3G-SDI to 12G-SDI conversion. The Muxer/DeMuxer supports 4K, UltraHD, 2K, HD and SD workflows and conversions from quad-link SDI signals to single link SDI signals, and vice versa at 12G, 6G, 3G and 1.5G bit rates. Both Square Division (Quadrant) and Two Sample Interleave (2SI) input and output mappings are supported.

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12G/6G/3G/HD/SD-SDI Distribution Amplifier

12GDA is a miniature 1x6 12G-SDI re-clocking distribution amplifier that allows facilities to save on cable runs and install times. With support for 12G-SDI for 4K/UltraHD single link workflows, the format-agnostic device features six separately buffered SDI outputs identical to the recovered input. It also offers automatic input detection, re-clocking and cable equalization, as well as a throw down package and LED signal detection indicator.

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The 12G-AM is an 8-channel AES audio embedder/disembedder Mini-Converter with support for 12G-SDI input and output up to 4K/UltraHD. Fiber models offer single link fiber I/O including LC and ST options. AES Audio disembedding is always functional, providing four AES outputs. Audio embedding is user selectable, on a channel pair basis, to either pass 12G-SDI input audio or to embed input AES audio from the breakout cable. The 12G-AM automatically detects and configures the input video standard.

12G-AM Models Available:

12G-AM 12G 8-Channel AES audio embedder/disembedder
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12G-AM-T with LC Fiber Transmitter
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12G-AM-R with LC Fiber Receiver
12G-AM-R-ST with ST Fiber Receiver

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The 12G-AMA is a 4-channel analog audio embedder/disembedder Mini-Converter with support for 12G-SDI input and output up to 4K/UltraHD single link with fiber I/O including LC and ST options. Audio disembedding is always functional, providing four analog outputs. Audio embedding is user selectable, on a channel pair basis, to either pass 12G-SDI input audio or to embed input analog audio from the breakout cable. Analog audio levels are selectable. The 12G-AMA automatically detects and configures the input video standard.

12G-AMA Models Available:

12G-AMA 4-channel analog audio embedder/disembedder
12G-AMA-R with LC Fiber Receiver
12G-AMA-R-ST with ST Fiber Receiver
12G-AMA-T with LC Fiber Transmitter
12G-AMA-T-ST with ST Fiber Transmitter
12G-AMA-TR with LC Fiber Transceiver

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12G-SDI to HDMI 2.0 Conversion

Hi5-12G converts a 4K/UltraHD/2K/HD 12G-SDI single-link input with eight channels of embedded digital audio to an HDMI 2.0 output with two or eight channels of audio. It includes a 12G-SDI single-link input with a re-clocked SDI loop out for simpler confidence monitoring or pass on for SDI pipelines.

Fiber SFP-equipped Hi5-12G models include the Hi5-12G-R receiver, which extends HDMI 4K signals over long distances from either an SDI or a Fiber connected source, and the Hi5-12G-TR transceiver, which delivers a 4K/UltraHD SDI or Fiber source signal to an HDMI destination with pass on of the source through SDI or Fiber to a secondary destination.

Hi5-12G is also available with a Fiber ST connector as the Hi5-12G-R-ST receiver, offering the same long distance benefits as its Fiber SFP variant.

Hi5-12G Models Available:

Hi5-12G   -   12G-SDI to HDMI 2.0
Hi5-12G-R   -   Includes 1x Fiber LC Receiver
Hi5-12G-TR   -   Includes 1x Fiber LC Transceiver
Hi5-12G-R-ST   -   Includes 1x Fiber ST Receiver

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HDMI 2.0 to 12G-SDI Conversion

HA5-12G allows users to convert an HDMI 2.0 input with up to 8 channels of audio from an HDMI source to two 12G-SDI single-link outputs.

The portable converter includes two SDI DA outputs and transmits 12G-SDI on each SDI link, reducing cable runs when transporting 4K/UltraHD over SDI.

A Fiber SFP-equipped HA5-12G model is available, the HA5-12G-T single-channel transmitter, which extends HDMI 4K signals over long distances (10 km Single-Mode).

HA5-12G is also available with a Fiber ST connector as the HA5-12G-T-ST offering the same long distance benefits as its Fiber SFP variant.

HA5-12G Models Available:

HA5-12G   -   HDMI 2.0 to 12G-SDI Coaxial
HA5-12G-T   -   Includes 1x Fiber LC 1-Ch Transmitter
HA5-12G-T-ST   -   Includes 1x Fiber ST Transmitter

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Optical Mini-Converters: FiDO 12G

The FiDO family of 12G-SDI/Optical fiber Single-Mode converters by AJA allows for the transport of 12G over distances of up to 10KM when using standard Single-Mode fiber optic cable. All our FiDO converters meet all relevant SMPTE specifications and are designed for multiple applications.


1-Channel 12G-SDI/LC Single-Mode LC Fiber Transceiver

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1-Channel 12G-SDI to Single-Mode LC Fiber Transmitter

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1-Channel Single-Mode LC Fiber to 12G-SDI Receiver

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2-Channel 12G-SDI to Single-Mode LC Fiber Transmitter

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2-Channel Single-Mode LC Fiber to 12G-SDI Receiver

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1-Channel 12G-SDI to Single Mode ST Fiber Transmitter, with SDI Loop Out

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1-Channel Single Mode ST Fiber to 12G-SDI Receiver, with Dual SDI Outputs

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openGear 12G


OG-DANTE-12GAM is an openGear, Dante audio embedder/disembedder, with dual 12G-SDI input and output ports providing up to 32-channels of audio embedding and 32-channels of disembedding simultaneously. OG-DANTE-12GAM provides the bridge between SDI and Dante infrastructures.

Dante audio networking provides digital audio distribution over local and wide-area networks with low latency, using standard network hardware or by connecting into a standard network infrastructure. This offers many advantages over analog, AES, and MADI infrastructures, including audio system scalability, easier installation, and simplified wiring.

A fully populated OG-X-FR openGear frame with ten OG-DANTE-12GAM cards, provides an incredible 640 channels of audio bridging in a rack-mountable form factor for a wide range of needs.

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The OG-12GDA-2x4 is an openGear compatible, state of the art 12G-SDI distribution amplifier. The incoming 12G-SDI signals on the dual input channels are automatically equalized and the outputs are automatically reclocked to four 12G-SDI outputs each. This dual input capability allows double the number of DAs in limited frame space. A 10x BNC rear connector module is included.

Designed for use in high density openGear 2RU frames including AJA’s OG-X-FR frame, new DashBoard software support on Windows, macOS and Linux offers remote control and monitoring of the openGear architecture and provides convenient and industry standard configuration, monitoring and control options over a PC or local network.

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The OG-FiDO-TR-12G is a state of the art, openGear compatible 12G-SDI/Fiber transceiver. Both 12G-SDI to Fiber and Fiber to 12G-SDI conversions are supported.

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OG-12GM is a compact SDI transport openGear card that enables 12G-SDI to quad link 3G-SDI and quad link 3G-SDI to 12G-SDI conversion. The muxer/demuxer supports 4K, UltraHD, 2K, HD and SD workflows and conversions from quad link SDI signals to single link SDI signals, and vice versa at 12G, 6G, 3G and 1.5G bit rates. Both Square Division (Quadrant) and Two Sample Interleave (2SI) input and output mappings are supported.

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Frame Syncs and Converters: FS4, FS-HDR


FS-HDR with Colorfront Engine™ Technology for SDR to HDR, HDR to SDR and HDR to HDR conversions.

The FS-HDR is a rack-mount, universal converter/frame synchronizer, designed specifically to meet the HDR (High Dynamic Range) and WCG (Wide Color Gamut) needs of broadcast, OTT, post and live event AV environments, where real time, low-latency processing and color fidelity is required for 4K/UltraHD and 2K/HD workflows. Developed in partnership with Colorfront, the FS-HDR’s HDR/WCG functionality is powered by the proven and highly respected Colorfront Engine™ video processing algorithms.

Besides integrated 3G-SDI, FS-HDR offers 4 optical fiber SFP cages for use with optional 12G-SDI HD-BNC or 12G fiber modules with support for 12G/6G SMPTE rates.

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FS4 offers Single-Channel 4K/UltraHD/2K/HD/SD or 4-Channel 2K/HD/SD Modes in a 1RU frame for conversion and frame synchronization.

The FS4 is a 4-Channel 2K/HD/SD or 1-Channel 4K/UltraHD frame synchronizer and up, down, cross-converter. AJA’s flagship frame synchronizer and converter offers incredible versatility and connectivity in a sleek 1RU frame for all your 4K/UltraHD and 2K/HD/SD conversion needs, with a wealth of digital and optional 12G-SDI Fiber LC and 12G-SDI HD-BNC SFP connectivity.

FS4 offers 4 fiber SFP cages for use with optional 12G-SDI HD-BNC or 12G fiber modules with support for 12G/6G SMPTE rates.

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You can configure your FS-HDR or FS4 with the appropriate SFP module by utilizing the AJA SFP Configurator

SFP Configurator

HDR Image Analyzer 12G

Waveform, Histogram and Vectorscope Monitoring for HDR

HDR Image Analyzer 12G delivers a comprehensive array of tools for the effective analysis of the latest HDR standards – including HLG, PQ and Rec.2020 – in 8K/UltraHD2/4K/UltraHD/2K/HD in a convenient 1RU device whilst utilizing the simplicity and convenience of 12G connectivity.

Developed in partnership with Colorfront® utilizing the Colorfront Engine™, AJA HDR Image Analyzer 12G supports a wealth of inputs from camera Log formats to SDR (REC 709), PQ (ST 2084) and HLG and offers color gamut support for BT.2020 alongside traditional BT.709.

Specifically designed to be used wherever needed, the 1RU form factor fits into a range of workflows, providing the confidence you need for consistent and predictable HDR production and mastering.

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Routers: KUMO 6464-12G, KUMO 3232-12G, KUMO 1616-12G

Designed for use in broadcast, production and ProAV, KUMO 6464-12G, KUMO 3232-12G and KUMO 1616-12G routers support large format resolutions, high frame rate (HFR) and deep color productions, reduce cable runs, and minimize points of failure when transporting 4K/UltraHD over SDI. KUMO 12G routers are also backwards compatible to all SDI formats.

Choose between KUMO 6464-12G, KUMO 3232-12G and KUMO 1616-12G, three compact 12G-SDI routers with 64x 12G-SDI inputs and 64x 12G-SDI outputs, 32x 12G-SDI inputs and 32x 12G-SDI outputs, and 16x 12G-SDI inputs and 16x 12G-SDI outputs respectively.

The routers mirror the physical form of AJA’s KUMO 6464, KUMO 3232 and KUMO 1616 routers, and add a USB port for easy configuration of IP addresses via AJA’s eMini-Setup software.

KUMO 6464-12G

Compact (4RU) 64x64 12G-SDI Router

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KUMO 3232-12G

Compact (2RU) 32x32 12G-SDI Router

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KUMO 1616-12G

Compact (1RU) 16x16 12G-SDI Router

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I/O: KONA 5, Io 4K Plus and T-TAP Pro


KONA 5 supports 12G-SDI I/O and HDMI 2.0 output. KONA 5 also supports HDR10 and HLG support over HDMI.

KONA 5 is AJA’s most powerful desktop PCIe card, offering a full set of professional video and audio connectivity with support for 8K/UltraHD2, 4K/UltraHD, 2K/HD, SD, High Frame Rate (HFR), High Dynamic Range (HDR) and deep color workflows. Reference In is included on the card itself and an included breakout cable connects you further through RS-422 and 8-Channels of AES Audio input and output.

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Io 4K Plus

Io 4K Plus supports Thunderbolt 3, 12G-SDI, and HDMI 2.0 I/O. Io 4K Plus also supports HDR10 and HLG support over HDMI.

Io 4K Plus is the cutting edge of capture and output hardware available over Thunderbolt 3, offering a full set of professional video and audio connectivity with support for the latest 4K/UltraHD devices, High Frame Rate (HFR), High Dynamic Range (HDR) and deep color workflows. The power of Thunderbolt 3 enables Io 4K Plus to handle a wide range of formats from 4K/UltraHD to 2K/HD and SD with frame rates up to 60p over both 12G-SDI and HDMI 2.0.

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T-TAP Pro is the newest generation of AJA’s proven T-TAP, featuring the latest 12G-SDI and HDMI 2.0 connectivity for working with up to 4K or UltraHD 60p video over a single cable. This allows for easy output of deep color, high frame rate, SDR and HDR video to a wide range of pro and consumer monitors and devices, all at the highest 10- and 12-bit quality. T-TAP Pro is a compact, silent device that delivers next generation mobile monitoring capabilities to any supported Thunderbolt 3 enabled system.

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With broadcast technology constantly evolving, AJA is uniquely situated to provide future-proof technology to broadcasters, production entities, post houses, facilities, live event venues and ProAV system integrators the world over.

To find an AJA Reseller in your area to purchase any of the 12G products described above, please visit our where to buy area.

Where To Buy