How to Adapt an Existing Multicamera Switching Setup for Streaming

If you’re like many people in the live audiovisual field who have lost a lot of jobs due to the COVID-19 pandemic, you are trying to adapt to the playing field and have a lot of expensive equipment sitting around that is not being used much. 在正常年份, half of my income comes from producing multicamera, live-switched events produced on location and completed in post. The “new normal” allows only for live-streamed multicamera virtual events. This shift has required me to adjust my workflow to meet my clients’ current demands in the most cost-efficient manner possible. 在本教程中, 我将讨论我所做的调整, explaining how to adapt the gear you have—with one additional minor purchase—rather than having to invest in a whole new streaming switcher.

我现在的工具包

The heart of my AV system is a Lumantek VS4 switcher (下面的图1). I chose it for its extensive feature set, ease of use, quality build, and low price. It has two HDMI inputs, one HD-SDI input, and one switchable HD-SDI/HDMI input for a total of four (图2，在图1下面). Each input has a scaler that will adapt it to the desired output up to 1080p60.

图1. Lumantek ez-Pro VS4切换器

图2. Lumantek VS4后面板I/O

超越切换器, 我通常有两到三个摄像头, 一台或两台笔记本电脑用于播放媒体, and a powered mixer that can handle at least five microphones and stereo audio playback. I like to record an audio feed from the mixer to each camera, as I am feeding speakers to the audience in the room. I normally feed the cameras the audio mix by putting a single UHF transmitter on a record out of the mixer, while having the cameras with receivers all tuned to that frequency. 拿到交换项目的硕士学位, I normally have a Blackmagic Design Video Assist recorder on the switcher’s HDMI or HD-SDI output for a high-quality recording.

Streaming-Capable解决方案

As COVID-19 has struck down almost every A/V job over the past year, production companies that weren’t focused on streaming before have had to adapt to stay in the game. Many have been adapting their existing video switching setup for streaming.

There are several products available to make this adaptation possible; some are more expensive than others. There are a number of standalone streaming appliances that don’t require a computer. They attach to the camera or switcher and connect to a network via Wi-Fi or a cellular network (using cell data). These appliances tend to cost a few hundred dollars, 需要一个数据计划, 而且很难配置.

另一个选择是USB 3.0 device that makes any HDMI- or SDI-connected device visible as a webcam. There are several such devices available from different manufacturers, 具有广泛的特性集, from multicamera switching functions to a single HDMI input.

Choosing a device from such a wide variety of options can be mind-numbing and expensive. 首先, 我排除了4K支持, at least as a differentiating feature that might increase cost. For the time being, I don’t really see a reason to stream more than 1080p. Considering most people are watching on mobile devices with small screens or laptops and aren’t expecting a 4K cinematic experience, 1080p is sufficient for nearly all current applications.

With that in mind, I looked for a solution that wouldn’t break the bank. AJA提供两种U-TAP设备, 一个带HDMI输入, 另一个带HD-SDI输入, 连接到USB 3接口.0 or 3.1 port to make whatever camera or switcher you plug into it appear as a webcam to the computer and allow you to stream. U-TAP HDMI (下面的图3)售价约为350美元.

图3. AJA U-TAP HDMI

Blackmagic Design’s Ultra Studio Recorder HDMI and HD-SDI are considerably cheaper, at $115, 但它们只在Thunderbolt中可用, which can be an issue if you are on a Windows PC, where Thunderbolt ports are either not present or inactive. (I have two HP laptops where the Thunderbolt ports worked under Windows 7 but haven’t under Windows 10.)

Blackmagic’s nifty Web Presenter ($495) offers both HDMI and HD-SDI video inputs that you can use as a two-input switcher, as well as a single XLR mic/line input and stereo RCA inputs. The device takes in up to 1080p resolution and outputs it at up to 720p over a USB 2.0连接.

Over the last year, Blackmagic Design has released two low-cost streaming switchers, the ATEM Mini Pro (595美元)和 ATEM迷你专业ISO ($895), which feature four HDMI inputs; the Pro adds multi-view. ISO (下面的图4) adds ISO recording for each input channel.

图4. 黑魔法设计ATEM迷你专业ISO

Matrox’s Monarch streaming devices and recorders offer basic single- or dual-channel streaming and recording for between $950 and $1,300. Once set up, the Monarchs don’t need a computer in order to stream.