ASI/SDI Selector Table - Explanation of Features

Note: In the Applicable Standards column, "ST xxx" refers to "SMPTE ST xxx".

Feature Applicable Standards Description
Micro BNC connector MIL-STD-348 Rev B Miniaturized version of a standard BNC connector, allowing for higher connector density. The low-profile DTA-2178 has a whopping 9 connectors (8x SDI/ASI, 1x genlock).
Please note that DekTec does not supply micro-BNC to BNC patch cables with these boards. For best performance, do not use patch cables. Instead, system-interconnect cables should be directly fitted with micro-BNC connectors.
Bidirectional port ASI/SDI port that can be configured from software, as input or output, and as SDI or ASI. Each ports can be configured independently from the other ports.
Relay bypass Hardware relay that automatically connects the SDI/ASI input to the output upon an application crash or PC power failure. This feature enables highly-available system configurations without requiring an external failover switch.
Genlock Method to synchronize SDI outputs to a 'genlock' signal that is connected to the genlock input port of the card. Both bi- and tri-level sync signals are accepted.
3G-SDI level A+B ST 425-0:2014 ST 425 describes three different mapping schemes for transporting video, audio and ancillary data into a serial digital interface operating at a nominal rate of 3 Gbit/s. DekTec supports Level A direct mapping of an uncompressed 1080p/50 or 60 video stream and Level B Dual Link (B-DL) dual-link mapping of a 1080p/50 or 60 video stream into a serial digital interface.
Payload identifier ST 352:2013 The "payload identifier" is an ancillary data packet that describes the characteristics of the SDI signal, including the picture rate, sampling structure, aspect ratio, bit depth and link assignment.
The Matrix API allows easy insertion/or and extraction of the payload identifier.
4K 2SI mapping ST 425-5:2015
ST 435-1:2012
2-sample interleave division, a method to map a 4K image to four sub-images.
2SI is defined in SMPTE ST-435-1. Each sample in a 2x2 block is put in a different sub-image. Each sub-image contains the full image, downsampled by a factor of 2 in horizontal and vertical direction.
2SI is the offical method prescribed by SMPTE ST 425-5, but in practice the informal quadrants method is used a lot.
4K quad link ST 425-5:2015 Method to transport 4K images over four 3G-SDI links.
DekTec cards support two mappings from 4K images to four links: 4K 2SI mapping and 4K quadrant mapping. The mapping method can be selected by software.
4K quadrant mapping ST 425-5:2015
ST 435-1:2012
The "Quadrant" method to map 4K images to four sub-images: Each sub-image is one quadrant (one quarter) of the 4K image.
This method is described in Annex B of the ST 425-5. This is an "informative" (=not normative) annex, yet in practice this method is used a lot.
4K to HD scaling Scaling 12G-SDI to 3G-SDI in hardware. The 4K UHD image is scaled down by a factor of 2 horizontally and vertically. HANC and VANC are taken from sub-image 1 (quadrant 1) in the 12G-SDI image. The software receives 3G-SDI, reducing PCIe bus bandwidth by a factor of 4. This feature can be used for monitoring or for creating a mosaic of 12G-SDI signals.


Audio bit depth ST 272M:2004 Each audio channel can carry 16, 20, or 24 bits per audio sample.
#Audio channels For SD and HD formats, the maximum number of audio channels is 16.
For full HD (3G-SDI) it is 32 and for UHD 128 channels of audio are supported.
Matrix API allows easy insertion (embedding) or extraction of all audio channels.
Audio sample rate ST 272M:2004 DekTec products support 48Khz sampling rate for all the audio channels.
Dolby® D/E ST 337:2015 Each audio channel can carry Dolby D/E® compressed audio (non PCM audio). Matrix API allows easy insertion/or and extraction of Dolby® D/E data.

ANC Data

Ancillary data ST 291M:2011 Ancillary data (also: ANC data) is non-video information embedded in an SDI stream. The DekTec Matrix API reads all ANC data packets present in an SDI frame and makes them available to your application, optionally filtered by DID (Data Identifier) and SDID (Secondary Data Idenfier).
Audio is also ANC data, but for ease of use, the Matrix API audio supports audio with dedicated data structures and API functions.
Closed captioning ST 334-1 SMPTE ST 334-1 defines the structure of packets carrying CEA-708, as well as CEA-608 closed captioning data, time code data, and ATSC A/65 closed caption descriptor information. Ancillary data packets with closed captioning are available to your application via the Matrix API by filtering on DID=0x61 and SDID=0x101 (CEA-708) or SDID=0x102 (CEA-608).
HDR/WCG metadata ST 2108-1:2018 SMPTE ST 2108 defines the transport of High Dynamic Range (HDR) and Wide Color Gamut (WCG) metadata in ancillary data packets. These HDR/WCG packets are available to your application via the Matrix API by filtering on DID=0x41 and SDID=0x0C.
Time code ST 12-1:2014
ST 12-2:2014
SMPTE ST 12-1 and ST 12-2 specify the format of time codes to label video frames, and the way time codes are encoded in ancillary data packets. Time codes in ancillary data packets are available to your application by filtering on DID=0x60 and SDID=0x60.
VBI data ST 2031:2007 SMPTE ST 2031 specifies how to carry data streams carried in MPEG-2 transport streams such as subtitles, teletext, WSS, SCTE127, AMOL, VITC, and CEA-608 data as ancillary data packets in the vertical ancillary data space (VANC). Ancillary data packets with VBI data are available to your application by filtering on DID=0x41 and SDID=0x08.

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