HardwareSoftware

The Moving Parts of a Big Production

I have a show this weekend—three sessions over three days. The instructor is teaching remotely. She needs to be seen and heard by the in-house participants and to interact with them in real-time.

And all of that needs to be live streamed.

This is what it takes to make that happen.

Teacher Video IO

Let’s start with the teacher. She’s insisting on using GoToMeeting to call in, so that’s what we’re using. I’m scheduling the meetings and providing her the links to connect. I’m taking the call on a new-ish iMac with two Thunderbolt ports.

Two things have to happen here:

1) We need audio and video coming out of this computer. This is our “camera”, so to speak, of the teacher.

2) We need to send audio and video into this computer of the action on the floor. This is the “camera” we’re providing to the teacher.

Audio out is easy: we’re taking the headphone jack into an audio mixer (we have a dedicated audio engineer on this job—more on that later). The video out is going Thunderbolt to HDMI into a Decimator MD-HX—an excellent HDMI to SDI converter box. From SDI we can bring it into our Blackmagic Design Smart Videohub. All of our video sources are going to go here.

Video in is coming through the second Thunderbolt port, courtesy of a AJA Io-XT. This is converting an SDI signal from the Videohub into Thunderbolt, for interfacing with the computer.

That’s the hardware. Software-wise, the Decimator is acting as a secondary display. I’m putting the GoToMeeting webcam feed from the teacher onto it, full screen. Then I’m sharing my “webcam” with her, which in this case is the Io-XT. It works natively with GoToMeeting, thank goodness.

Is this already too complicated? Because I’m only getting started.

Cameras, Switcher and Wirecast

We have three Sony XDCAMs on the floor. These all have multiple connections (SDI, XLR, Comm, etc.) patching into various wall plates around the perimeter. Those all terminate below the building at a much larger wall plate. A snake (a huge bundle of cables) runs from there to our production trailer outside.

That’s how our cameras all get to the Videohub.

We have the Videohub routing video in many directions. We’re sending each camera to its own AJA Ki Pro, from which we record the individual cameras. We also route each one to our (admittedly aging) Panasonic AV-HS400A switcher. This is where our producer does his live edit. That, too—like everything else—runs back into the Videohub and out to its own Ki Pro for recording.

We’re also sending the live edit to a second Io-XT, from which we connect Thunderbolt to a laptop running Wirecast 7. That’s the software we’re using to broadcast to our online participants.

Audio Mixes

Audio is a tricky thing here. We can’t send the teacher the same mix that we send to the online participants because that mix includes her voice. She’ll hear an echo of everything she says—very disorienting. So our audio engineer is making two mixes: one with the teacher and one without.

We’re dedicating one of the cameras on the floor to be the teacher’s eyes and ears. But before we send that video to the iMac and GoToMeeting, we need to marry it up with the teacher-less audio mix.

This is where we’re doing something a little hack-y: we’re using a Ki Pro to embed the audio. We’re connecting the video SDI via the Videohub and the audio XLR from the mixer. A Ki Pro is too expensive to act as an audio embedder, but it’s gear we have, and it works. We’d be better off buying something like this AJA HD10AMA.

The Floor

Finally, we’re routing the teacher’s video feed from the Videohub to a projector and screen on stage. The in-house participants will see her front-and-center, larger than life. Audio gets sent from our mixer to another one on the floor, which is operated by a second audio engineer. That person mixes the in-house levels.

And that, as they say, is that.

The teacher can interact with the participants in real-time, a live edit is made and broadcast, and every individual video source gets recorded—including the live edit and the teacher’s webcam.

Easy, right?

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