photonSDI is an open source implementation of the Serial Digital Interface (SDI) standard that is widely used in professional video equipment. Open-source hardware has the potential to revolutionize videography, but current improvements made by the developer community, such as on-camera video processing or color grading, are not accessible to professional videographers. The limitation is because professional video equipment uses the SDI video interface or writes the video stream directly to a solid state drive (SSD), but the open-source cameras currently support only the consumer video standard HDMI.

photonSDI strengthens the open-source hardware development community by providing foundational components to make open-source camera improvements accessible to professional videographers.

Design Goals

To make open-source cameras such as the apertusĀ° AXIOM [link] a drop-in replacement for existing professional video equipment.

The photonSDI system consists of 1) a development test system with two off-the-shelf circuit boards: an evaluation board and an SDI interface board to handle electrical conversion. 2) A prototype implementation of a custom caseboard that plugs directly into the Axiom Camera and adds SDI connectivity


The initial development of the photonSDI gateware was sponsored by the German federal ministry of education and research (BMBF) via the Prototype Fund.

How it works

A description of a desired SDI connectivity is created using the LiteX and Migen frameworks wich then generate a Hardware Description Language (HDL) reprensentation in Verilog. The HDL is passed to the tool chain, which generates a configuration for the chip on the evaluation SDI Extension Board. The configuration is loaded onto the chip on a base board that is plugged into the camera. Camera with chip has new functionality for connecting to professional SDI video equipment.

Technical Details

The implementation is still work in progress.

Implemented in: Hardware description language loaded into chips LiteX and Migen Python frameworks for building custom hardware.

Supported hardware platforms: Field programmable gate array (FPGA) evaluation board AC701 + SDI interface evaluation board TB-FMCH-12GSDI Camera Apertus AXIOM beta + AXIOM SDI extension board

Source code is available on GitHub.

Projects using photonSDI

apertusĀ° AXIOM beta open source cinema camera project

TimVideos HDMI2USB presentation recording and streaming system