Managing Inputs And Outputs For Video Conferencing Platforms and Webcasts
Single Meeting Space
Remote presenters join a single meeting space (such as a Zoom Room), along with the A/V tech director. The A/V tech director separates each presenter feed by using a dedicated laptop or desktop computer for each presenter, fullscreen and without window chrome on a second monitor, which is exclusively captured by the HDMI output on the computer. In my setup (Figure 3, below), my Roland V-60HD switcher appears as the second monitor in Windows or Mac OS running a Zoom meeting.
Figure 3. Zoom presenter feeds as HDMI inputs to video switcher hardware
Alternatively, you can use one or more HDMI capture interfaces on another laptop or desktop computer running a software-based video switcher such as Telestream’s Wirecast, vMix, or OBS (Figure 4, below). Any interactions between the presenters can occur in the Zoom meeting space.
Figure 4. Zoom presenter feeds as inputs to video switcher software
In this scenario, though, you want to make sure you have the switcher set to follow the audio of the active presenter input. Otherwise, you’ll likely hear overlapping duplicate audio tracks that are out of sync with each other by milliseconds. Another variation of this scenario separates each presenter into his or her own Zoom meeting, which requires a more complicated setup for return audio if the presenters need to interact with each other.
Discrete NDI Feeds for Presenters
Another approach is for remote presenters and the A/V tech director to use a meeting space, such as Microsoft’s Skype, that can output discrete NDI feeds of each presenter (Figure 5, below). Skype has an NDI option available in its advanced preferences. Only the A/V tech director needs to enable this option. Each presenter joins a group Skype call, which is initiated by the A/V tech director. Each presenter’s feed is automatically broadcast over the local network and is available to be used by any computer or device that’s capable of accepting NDI inputs.
Figure 5. Skype presenter feeds as NDI inputs to video switcher software
Wirecast, vMix, and OBS all support NDI inputs. The quality of the Skype NDI output, though, will vary based on each presenter’s video input and connection quality. (Note that Skype’s NDI output does include a small and unobtrusive Skype bug in the top-right corner of the frame.)
Combining On-Site and Remote Presenters
Another variation of remote video contribution combines on-site presenters with remote presenters, just like you’d have in a TV news broadcast with an on-site host and remote guest. In this scenario, the challenge is a return program or aux feed of the on-site presenters to the remote presenters, allowing them to interact with one another. Figure 6 (below) depicts the inputs and outputs used for a virtual event with an on-site emcee and remote guests.
Figure 6. On-site host with remote guests
Other Solutions for Remote Video Contribution
These are just a few of the options that you can consider for putting together your next virtual event broadcast. Also, there are entire systems dedicated to remote video contribution that don’t involve the use of videoconferencing platforms such as Zoom. One example is Sienna ND software. It’s utilized by broadcasters to connect remote studios to each other, and it has an appropriate price tag (licensing starts around $7,000).
Tools such as Wirecast and vMix have “call-in” modules to enable remote contribution via WebRTC sessions running directly in the switcher.
Softvelum’s free Larix Broadcaster can turn any smartphone into an SRT input for a remote cloud-based switching system as well.
It’s beyond the scope of this article to discuss all of the available remote contribution options, but rest assured that new offerings continuing to hit the market have the potential to expand every webcaster’s toolkit.
Jan Ozer will lead workshops, presentations, and panels covering advanced codecs, gear for remote productions, WebRTC, low latency, and reducing bandwidth and storage costs at Streaming Media East in Boston May 23-25.
Robert Reinhardt's workshops will cover the latest tips and tricks for using FFmpeg and managing inputs and outputs for videoconferencing, while presentations and panel discussions will look at taking your webcasting and event streaming efforts to the next level.
Companies and Suppliers Mentioned