Chris Brown's Arduino MKR Vidor 4000 Carrier Is "Possibly the World's Cheapest SDI Signal Generator"
Designed as a test device for Serial Digital Interface (SDI) circuits, this FPGA-powered gadget pushes signals at 1.485Gbps.
Chris Brown, of sports media technology firm Tempus Ex, has designed "possibly the world's cheapest SDI signal generator" — based on an Arduino MKR Vidor 4000.
"In the world of professional video, SDI (Serial Digital Interface) is the industry standard for getting video from point A to point B," Brown explains by way of background. "It's the professional's equivalent of HDMI for consumer electronics. At any large-scale, televised event, you can bet that somewhere behind the scenes, there's a rat's nest where all of the video comes together and is distributed via SDI."
As you might expect from something aimed at professionals, SDI hardware is typically priced towards the upper end of the market — but, Brown points out, while SDI can offer high bitrates, the standard itself is relatively simple. To prove it, he's designed a low-cost SDI signal generator — which he describes as "the 'hello world'" of SDI hardware.
"To keep it simple, we'll just make the signal some flashing colors. And we'll aim to make this a 1080p30 signal, which can be transmitted via HD-SDI," Brown writes. "In theory, we just need to program a microcontroller that can send a 1.485Gbps signal to a cable driver. This would work if we could get our hands on such a microcontroller, but 1.485Gbps is quite fast. To be able to generate a signal at that speed, we'll need an FPGA, which can be programmed using a lower-level hardware description language to perform much faster operations."
The Arduino MKR Vidor 4000, handily, has both a microcontroller and an Intel Cylone 10 FPGA — just what the project needs. While its performance sits somewhere below the level required for nearly 1.5Gbps of data throughput, a Semtech GS2962 serializer finishes the build — in which ten data lines, each delivering 148.5Mbps, are run in parallel to hit the performance level required.
"As far as I know," Brown writes, "this is the first time an Arduino has been capable of generating and emitting arbitrary SDI video signals, and as far as I know, this is also the cheapest SDI signal generator available anywhere. SDI signal generators typically cost anywhere from $350 to $2,000. This one costs ~$87 for the Arduino and ~$95 for the transmitter parts and assembly at low volumes. Although I don't recommend using an Arduino like this in mission critical workflows, it can be a valuable tool in the lab."
Brown's full write-up is available on the Tempus Ex blog, while the design files and source code are available on GitHub under an unspecified open-source license.