Case Study: Mobile, iOS-based, Live-Switched Streaming

Wi-Fi

Being out in a public event, I did not even try to use the available “public” Wi-Fi. Instead, I used my own cell phone as a hotspot. Previously, I’d used this hotspot and the iPhone’s Wi-Fi as the access point (AP) router for all the connected devices, but even having only one remote camera meant that there were three streams going through the phone AP: AP to iPad,iPad master program to AP, and then upstream LTE from the phone. The remote camera was choppy even though it wasn't too far away.

This time, I had two remote cameras coming in to the iPad so the number of streams added up quickly. I decided to use a separate AP/router to reduce the computing load on my cell phone/hotspot. It looked like this:

• Camera 1 to AP
• Camera 1 from AP to iPad
• Camera 2 to AP
• Camera 2 from AP to iPad
• iPad master program to AP
• Master program from AP to cell phone for upload to web

Another key feature of the device I chose was that it was also self-powered. It was one of these little “media hubs” designed to share movies or content on a USB stick or memory card with several people over Wi-Fi. I didn’t use the sharing capability—just the fact that it connected to my phone—and shared that connection with multiple other devices. It did this all afternoon and the battery level went down only one tick.

The downside with this solution was that everything has to go wireless, and even these six streams may have been too much for this very basic 2.4GB AP. I have since purchased a small USB-powered AP that can connect to my phone via a wired connection, and that also offers a wired LAN connection that I can use to deliver all the streams to the iPad (via an Ethernet adapter). This means the only wireless data it would need to handle is the camera to the AP. Everything else would be on wires.

Additionally, the little pocket AP I used relies on internal antennas. These are not the best solution when you need distance, or are competing against a bevy of existing Wi-Fi signals (i.e., noise). You can see this in the second sample clip from the event where the close camera looks good, but the distant camera is operating at a much lower frame rate. In the middle of an office park, there may have been 50 or more different Wi-Fi access points all congesting the airspace.

The new AP has two external antennas I can swap out for larger antennas with additional gain. This means it can hear the cameras better and from a greater distance with more reliability. There is actually two-way communication going on because I can remotely control the distant iPhone cameras—zoom, set focus, and other aspects—from the iPad. So a reliable connection is an important goal.

Master Control

There are lots of portable streaming solutions out right now. These options range from computer-based solutions such as Telestream Wirecast and vMix to standalone solutions that require dedicated hardware, such as the NewTek TriCaster and Sling Media SlingStudio. SlingStudio has the lower-cost initial purchase with its $1,000 Hub (Figure 4, below), and you need an iPad to run the switching app. I have been testing two iOS apps that use an iPad, but require no additional hardware purchase.

Figure 4. SlingStudio Hub

Teradek Live:Air Action is a free app with paid upgrades to add cameras, enable recording while you stream, and other features. But once you pay for them, you're good. The other solution is Switcher Studio. The app is free, and it's all in. You get built-in titles, nine cameras, picture-in-picture effects, but there’s a monthly fee to be able stream or record. There are other differences but this is not a comparison app review; that will come later.

For this event, I used Switcher Studio on my iPad Air. The iPad is the control surface for everything. Camera 1 is the iPad. Camera 2 is the one I’m holding in the video that accompanies this article. Camera 3 is the other phone with the telephoto lens on it. With Switcher Studio, I can even do Cameras 1 and 2 at the same time, or even Cameras 1, 2, and 3 (Figure 5, below). These effects look pretty polished.

Figure 5.  Compositing three camera sources with Switcher Studio

Using the Switcher Studio to pull together this live-switcher shoot at the Frisco Arts Walk, I reliably pushed six Facebook Live “hits” from various locations at this outdoor event with everything I needed carried on two tripods. The bigger tripod had the iPad Air with its normal rear camera. On top of that I mounted the iPhone 5 with wide-angle lens. On one arm, I had a board with my mixer, music source, and the mixer’s battery pack. On a second accessory arm, I had my cellphone which was the mobile hotspot. In a gear bag hanging off the tripod, I had the access point and the microphones. I had the receivers for the microphones and the shotgun mic all attached to the iPad's iOgrapher case.

On a second, lighter tripod, I had the second iPhone 5 in an iOgrapher case with a 2x lens on it. I would arrange this to be a different view—usually the closeup view of the interviewee. I also used it for a distant view of the interview to give a sense of the outdoor environment where this event was taking place.