Portable Streaming Encoders Shrink and Grow

Contribution on a Small Scale

For those handling slightly more extensive client needs, a number of portable encoders are shipping with forward error correct (FEC) and network-shaping features. Typically, the FEC approach is to increase the number of packets being sent, including redundancy of select packets, based on various criteria of importance, priority, or keyframing.

The idea of FEC, also known as packet flooding, is that these additional packets—which increase the other bitrate of the origin stream—will make it through to the destination if the primary packets do not. With enough of the original, redundant, or FEC packets making it from the contribution site to the origin server, an entire frame can be reconstructed for uninterrupted delivery.

There are a few key FEC solutions in the marketplace, led by open source options (Secure Reliable Transport or SRT) and paid options (Pro MPEG, Zixi, etc.). Each has its benefits and drawbacks, which Help Me Stream will be testing in a forthcoming report, but the key takeaway for this article is the fact that these FEC solutions are finding their way into portable encoders.

“We do a lot of work with Zixi for backhaul and contribution from various customer sites,” said Mark East, chief problem solver at 090 Media, during the July 2018 SMAdvancedForum webcast. “So we’ve been looking at a number of similar solutions. First is the Osprey Talon G1, very, very, small form factor."

Indeed, the Osprey Talon series of encoders are slightly larger than an SDI-to-HDMI converter box, but offer a wide range of options.

“A slightly larger form factor, but higher capabilities, would be T-21’s AVC encoder (Figure 3, below). They also have an HEVC 4K encoder that's exactly the same form factor but a little bit pricier,” East continued. “The commonality here is that both of these units support Zixi, and one of them—the T-21—also supports SRT. So we're looking at them as true contribution encoders.”

Figure 3. The T-21 AVC encoder

That’s a distinct change from less than 2 years ago, when FEC, contribution encoding, and portable encoders often couldn’t be said in the same sentence.

“They also both support RTMP, and the T-21 supports HLS as well. So we’re looking at these as being problem solvers out in the field, not just for contribution but for stream encoding to services like YouTube and Twitch and the like.”

Multiple Cameras, Multiple Streams

At the top of the article, we mentioned connection types. What about those devices that have multiple connectors?

While most of the appliances allow only one audio and one video input to be used at any given time, the Epiphan Webcaster X2 has two USB ports, and one of these ports can be used to connect a second camera. With this feature, currently in beta, a second camera can be connected via one of the USB ports, allowing dual camera inputs to be switched back and forth between the USB and HDMI connectors.

Who Needs Electricity?

As portable encoders continue to shrink in size, the power consumption requirements are also dropping.

Given the small size of the Talon, compared to many contribution encoders, the power consumption requirements are also lessened. The G1 series uses a standard 5.5mm x 2.1mm 12v barrel connector, which makes it easy to connect to any 12v source. The Talon also follows the path of several small-form-factor computers—such as thin mini ITX mainboards and Intel Next Unit of Computing (NUC)—that offer wide voltage ranges in case a particular power source is not available.

The Talon encoders “feature a fanless design with a low power consumption of <6W,” Osprey writes on its product sheet, adding, “The wide input voltage range of 9VDC–17VDC also make it a perfect candidate for battery operated equipment and installations.”

The Magewell Ultra Stream, which is even smaller than the Epiphan Webcaster X2 unit, uses less than 3 watts (5v at 300 milliamps).

One additional benefit that comes in several of these DC-powered appliances is an ability to auto start after a power outage. This may not seem like a big deal when you’re using a portable encoder in a fixed location in a venue, but for those out in the field it’s helpful if a brownout occurs (e.g., battery power falls below a certain output level and a secondary battery has not yet taken over as the main power source). Even for those who are only streaming venue events, the wide voltage and DC-based power requirements mean that a backup battery might be an inexpensive form of insurance worth lugging along to keep the show going.