Skip to main content

Blackmagic HD Link Optical Fiber

Whether it’s HD-SDI, 3 Gbps, or 2K video, we’ve all probably wished for at least one flavor of such exotic video in our studios. And as the DTV evolution has rolled out, many of us have gotten our wish. However, as with a lot of wishes, some of us have had to face the reality of “what do I do with it once it’s here?”

After such an ultra high-quality product arrives, we have to route it, manage it, store it and distribute it. And of course, these days many capital projects are trimmed to the bone. While broadcasters may be tripping over analog monitors and other such gear in our storage areas, most of us are a bit understocked when it comes to equipment that can handle high-definition video and surround AES audio signals.

Until recently, monitoring HD video and embedded surround sound has not been simple or inexpensive. Black-magic Design, a leading manufacturer of innovative professional audio/video products, is changing the marketplace by offering such innovations as the HDLink Optical Fiber. While the standard HDLink gear allows high quality monitoring of HD video signals via LCD monitors, the HDLink Optical Fiber extends such capabilities by allowing distribution over optical fiber.

The Blackmagic Design folks arranged for me to try out one of their new HDLink Optical Fiber units. And when I informed them that I didn’t have a lot of installed fiber technology, they sent along one of their Optical Fiber Mini Converters and a length of fiber for tying everything together.


The HDLink Optical Fiber measures approximately 9 x 3 x 1-inches and the unit’s connections are all arranged on one side of the enclosure. It’s powered via an external 12 VDC adaptor. I/Os include monitoring for embedded audio, a DVI-D or HDMI connection, an SDI input and output, optical fiber in and out, and a USB connection. (When using DVI-D, there’s no audio present on the DVI connector. However, the use of HDMI can provide audio via the DVI connector.)

The HDLink Optical Fiber is a full bandwidth device with both 3 Gbps SDI and optical fiber inputs. These accommodate 4:2:2, 4:4:4, and 2K standards. The supported HD formats include 1080 lines at 24p, 25p, 30p, 48i, 50i, 60i, and 720 lines at 50p and 60p. HDMI supports video and audio at 1080p/24, 1080i/50, 1080i/59.94, 720p/59.94/50 and NTSC/PAL. The unit also supports 2K 2048x1556 video for a 30-inch DVI display. Color support is 4:2:2 10-bit YUV, 4:4:4 10-bit RGB and 2K 10-bit RGB.

Blackmagic recommends a resolution of 2560 x 1600 when working in 2K, and 1920 x 1200 is recommended when running 1080 HD formats. For 720 HD applications, a resolution of 1280 x 800 is suggested, with all frame rates running between 48 and 75 Hz.

The video input automatically detects either an SDI or optical fiber input, and both are always active. Built-in 3D lookup tables ensure accurate colorimetry, and the included utility software for Windows or Mac OSX allows real-time color adjustments.

The Mini Converter Optical Fiber is a smaller sibling to the HDLink, with basic connectivity that allows bidirectional conversion between HD-SD/SDI and optical fiber. Format specifications are similar to the HDLink, including SD/HD, 2K and 3 Gbps varieties.


To get things started, I connected a fiber cable between the HDLink Optical Fiber and the Mini Converter Optical Fiber and provided a SMPTE 292 signal to the input of the Mini Converter. I next added an Evertz 2430 DAC-HD (for conversion to VGA) to the SDI output of the HDLink Optical Fiber. The Evertz unit drove an OptiQuest VGA monitor. Then it was time to apply power to everything. Almost immediately I observed a crisp, clean HD image on the monitor. This proved that both units were indeed working properly.

For my next test, I needed an HD SDI source with embedded audio. This was not a problem, as we’re an NBC affiliate. I connected an HD output from our affiliate distribution amp to the input of the Mini Converter. To monitor audio from the HDLink Optical Fiber, I connected the outputs to an audio amplifier wired to some bookshelf speakers. As soon as I made the last connection I had channels one and two coming in loud and clear. NBC happened to be running a stereo commercial. When regular network programming resumed in 5.1 surround, all I heard on channels one and two was a hint of ambient sound (left and right front surround). Relocating one of the RCA connectors to channel 3 solved the problem, as I found “normal” dialog there.

Finally, for the HDMI test (bypassing the Evertz), I attached a Viewsonic VX2025wm monitor and connected the HDMI cable between the monitor and the HDLink Optical Fiber. A beautiful picture with NBC HD content appeared on the screen.


Initially I figured that this review would have me on some sort of learning curve, but I received a pleasant surprise. No matter where you connected signals to the BMD boxes, something came out of every spigot. No homework was required and there was nothing to set up (other than the lookup tables, should you choose to do so). I should also note that even after several days of continuous operation, the power adaptor and HDLink Optical Fiber were barely warm.

It would be nice if the HDLink Optical Fiber could downmix the six surround audio channels to provide a stereo output, but this is a very minor shortcoming as this thing is already as handy as a shirt pocket. The biggest problem I had during my test period was keeping it in one place. We’re in the process of updating our downstream line for HD with embedded audio and someone was always running off with the Blackmagic unit to check audio or video. When you get one, you’ll need to keep an eye on it, as it could easily grow legs.

Joey Gill is chief engineer at television station WPSD in Paducah, Ky. He has been with the station for 25 years and has worked in broadcasting since 1977. He may be contacted