Livestreaming

From Smoke Academy Wiki

Livestreams are a key part of Smoke TV's programming. Live video is becoming more popular, and platforms like Twitch, Youtube, Periscope and Facebook all offer live broadcast functionality.

The production gallery for the first SU election debate, 2016. The encoding PC (left), Blackmagic ATEM system (middle), XR18 audio mixer (far right) are in use here.
Diagram of a typical livestream setup, using four cameras and four microphones.

What do I need?

At Smoke TV, there are several pieces of equipment that allow a broadcast:

  • Cameras and microphones to gather audio and video from your show
  • A vision switcher combines your video sources from your cameras together into a single programme
  • An audio mixer combines your audio sources together
  • An encoder continuously sends the finished programme to the internet
  • Shows are normally published to the web using a service like Facebook or Youtube.


You should carefully consider where to place your cameras, where your sound will come from, and where you will set up your production gallery (the place where you manage and produce the programme).

Should it be live?

Livestreams are more work. They need a larger team, more equipment and more preparation. However, for high-profile events, they're a good option because there's no need to edit the footage before publishing it, and they're a great chance to score some real-time engagement from your audience. They're also more fun!

Video

A typical three-camera setup: one master and two close-ups.

Think about the number of camera angles you will need. Then work out how many cameras you will need to achieve these angles. Will these cameras be on tripods or handheld? Plugged in or battery-powered? Will they need to be raised above an audience? How frequently will they need to be moved?

Your cameras will need to be plugged into the central vision switcher using SDI cables. Make sure that your cables are long enough to reach all of your camera positions.

The Blackmagic ATEM out of its usual housing. Video inputs are on the left, and outputs on the right.

You will then want to set up your vision switcher. There are two options:

  • Use the Blackmagic ATEM - this is a dedicated vision switcher which accepts up to six cameras at once. This is the best option for large productions.
  • Use Wirecast computer directly - you can plug up to four cameras straight into the computer which runs Wirecast, allowing one person to switch the cameras and take care of graphics. This is better for small projects with fewer crew members.


If you use the Blackmagic ATEM, remember that it needs to be controlled by software running on a separate computer, usually a Macbook or other laptop. You also need to bring a spare SDI cable to take the video feed from the ATEM into the encoding computer.

Audio

A typical XLR cable.

You will need to think about the audio sources your show needs. Normally, you'll want to give a handheld or wireless lapel microphone to every person who will be speaking on screen. You might also have music or environmental sound (especially at big events) to consider. Whatever you decide, all of those sources of sound will have to be plugged into an audio mixer.

You will probably use XLR cables to connect most of your microphones to the mixer. These have characteristic three-pin connectors. Make sure you have enough cables of the correct length before you finalise your plan.

The mixer will convert the sound to USB, which you can then plug into your encoding computer as if it were a normal USB microphone.

Depending on the size of your show, you might decide to use:

  • Small USB soundcard - for small shows where the sound is being handled by someone else
  • Alto 1202 mixer - for mid-size shows with a few microphones
  • Allen and Heath QU16 - for very large shows with a lot of complexity
  • Behringer XR18 - for very large shows with a lot of complexity


For some broadcasts, audio needs will be handled alongside Smoke Radio.

Encoding

The Wirecast interface.

The encoder is normally a piece of software running on a computer. Encoding live video is hard work for the computer and the internet connection, so it's vital to check that both are fast enough to handle the quality of video you want to broadcast at.

Smoke TV use encoding software called Wirecast, which has a ton of extra features alongside sending video to the internet.

Wirecast allows you to:

  • Add graphics like scoreboards and lower thirds
  • Play pre-recorded videos like intro and credits VTs
  • Use smartphones as camera sources in your programme, using a companion mobile app.
  • Record the programme locally on your computer


Wirecast is divided into layers, which work the same way as layers in Photoshop. You can add "shots" to each layer, which can be live cameras, pre-recorded videos, graphics, etc.

You can see a tutorial on Wirecast basics here.

Publishing

The final piece of the livestreaming puzzle is where you want your viewers to be able to watch from. Normally, Smoke TV broadcasts simultaneously on Facebook and Youtube, but any streaming service is possible in principle (eg. Periscope, Twitch).

Facebook and Youtube both automatically and record live shows and make them available for viewers to re-watch later. Youtube videos can be embedded alongside a liveblog on the Smoke website.

A word on cable management

Most livestream projects involve a lot of cables. This can pose a serious trip hazard if not dealt with properly. Before you start to set up, think carefully about where you are going to run cables. Make sure they are neat, out of the way of crew and audience members, and (most importantly) taped down. The University and the Students' Union are likely to shut down projects if they believe that safety is at risk, so don't take any chances here.

More info

You can find out more about the topics covered here at: