This article will review the basic aspects of setting up a livestream for your competition. The sections that follow provide information about the different kinds of cameras you might buy or use, video mixing, overlays, audio, and some recommended equipment. Livestreaming is recommended for experienced Event Partners who are already confident in their ability to organize and run an event using the RECF Competition Portal.
Equipment and Setup for Video & Network
Overview
Let’s take a look at a basic video setup for an Aerial Drone Competition with two fields. Each field has a camera pointing at it.
Note: Take care that the camera position does not interfere with the flight area for the drones or may provide a competitive advantage if there are areas that are intentionally hidden from view for the pilots.
The RECF Competition Portal has an overlay option that generates the graphics that will add information about teams, time, match number, and score to the live stream with an integrated green screen. See the Overlay Settings article for more information.
These inputs go into the video switcher, which overlays the graphics from the Competition Portal onto the camera feed to create a single, combined video.
The resulting video is sent to outputs, including the livestream platform (e.g., YouTube or Twitch) and a TV or projector in the venue that is visible to the audience.
Video Switcher
Basic Functions
- Superimpose the RECF Competition Portal graphics over field video
- Switch between cameras to show the current match/field
Additional/Advanced Functions
- Combine multiple camera feeds together in various ways
- Add transitions/animations between cameras or scenes
- Provide additional customization and effects as desired
Ways to Handle Video Switching
- Dedicated video mixer (hardware)
- Cameras plug into the mixer
- Switching and other options controlled by buttons and sliders
- Expensive and requires some expertise
- Unnecessarily complex for most events
- Not the focus of this article
- OBS (Open Broadcaster Software) Studio, available at obsproject.com
- This article doesn’t discuss how to use the OBS video mixing software, but it is very widely supported with lots of searchable information about its set up, configuration, and use
- Runs on a Windows, macOS, or Linux computer support for external displays
- Free and open source software
- Widely used and supported
- Standard solution for amateur or semi-professional livestreaming
- Wide range of online tutorials
- Easy to get started with
- Simplifies advanced features like custom transitions
Networking for Livestreams
- Stream computer should have a hard-wired (ethernet) connection to the internet
- Run your own network instead of relying on the venue’s WiFi!
- A less expensive WiFi router is fine to start with
- Connect WAN port on router to venue’s wired internet
- Connect essential devices to router via ethernet cable
- Non-essential devices (scoring tables, pit displays) can connect via WiFi
- Every venue has different setup and policies, but almost every IT department is helpful and accommodating if you communicate with them ahead of time
Cameras
General
- One camera pointed at each field
- Need to get video from cameras into computer/OBS somehow
- How? Depends on the type of camera
- Each camera should have a wide field of view (FOV)
- FOV is typically listed in degrees; larger number of degrees is a wider FOV
- A wider FOV allows you to put the camera closer to the field and still get the whole field in the shot
- A very wide FOV can make things look distorted (fish-eye effect)
- Should have 1080p or better resolution
- Lower than that won’t look good
- 4K is fine, but is not necessary because the livestream will probably end up at 1080p
- Good overall quality
- Resolution isn’t everything
- Read/watch reviews, test equipment, etc. if possible
Types of Cameras
- Cameras: TL;DR
- NDI cameras: Best overall choice
- Best balance of cost, reliability, and performance
- USB cameras: Good if you need to minimize cost
- Inherent issues with running USB cables over long distances means NDI is probably a better choice if you can afford it
- HDMI and SDI cameras: Not the best choice
- Great if you want to use equipment you already have…
- …but not the best place to look if you’re starting from scratch
- NDI cameras: Best overall choice
- USB Webcams
- Pros
- Cheap
- Easily available
- Lots of different models
- You may already have access to some
- Cons
- Require USB cables that run over relatively long distances (30-40 feet), which is not foolproof
- USB bandwidth on a computer can be a concern, and each camera should be plugged into a separate USB port (multiple cameras on a USB hub can lead to dropouts)
- Options for running USB over long distances
- USB extension cables
- Extension cable runs between the computer and the camera’s USB cable
- Relatively cheap, readily available, and easy to use
- Can be flaky depending on model, and USB isn’t really designed to run over long distances
- Some extension cables have large repeaters or boosters in the middle of the cable that can create physical obstacles on the floor between the computer and the camera
- Non-powered and USB 2 are generally fine for 1080p resolution, but you should test it with your cameras; USB 3.0 with external power isn’t usually necessary for this application
- Monoprice brand USB extension cables are reportedly a good choice
- USB over Cat5 (ethernet) cable
- Cat5 cable is more reliable than alternatives
- Cheap, easy to run, and designed for long cable runs
- Additional cost for transmitter, receiver, and AC adapter kit
- Transmitter on the computer end connects to a USB port
- Receiver on the camera end is powered via an AC adapter and the camera’s USB cable
- USB extension cables
- Pros
- Network Cameras
- Pros
- Cat5 network cable is cheap and designed to run over long distances
- Many network cameras can get power and network connection over a single power-over-ethernet (PoE) cable
- Wireless, battery-powered WiFi versions are available, although battery life may be a concern
- Because video goes to the stream PC over the network, there’s no need for capture cards or USB bandwidth
- Cons
- Higher cost compared to USB webcams
- What to avoid
- Lots of cheap network cameras are designed for use in security systems
- Video quality is often not a high priority for security systems
- Multiple seconds of latency is fine for security applications, but for broadcast you want as close to 0 latency as possible
- Lots of cheap network cameras are designed for use in security systems
- Better option
- NDI network camera
- Network video protocol designed for broadcast applications
- Low latency
- Can work over wired or WiFi setup with high quality video
- Plugin for OBS makes it easy to get NDI sources into your livestream
- Network video protocol designed for broadcast applications
- Good NDI camera at the time this content was created
- HuddleCamHD Pro IP, $329
- NDI network camera
- Power Over Ethernet (PoE)
- You need injectors or a PoE switch to power PoE devices
- Connect the PoE switch to a power source
- Connect PoE devices to the switch
- There are multiple standards, but you probably need PoE+ (IEEE 802.3at)
- You need injectors or a PoE switch to power PoE devices
- Pros
- HDMI Cameras
- Pros
- You may already have suitable cameras with HDMI output and a good field of view (e.g., GoPro)
- Cons
- Running HDMI over long distances isn’t trivial
- While 30, 50, and 100 foot HDMI cables are available, they’re bulky and some need external power at the camera end
- Camcorders or photo cameras with HDMI out are probably not a good choice, because the field of view is too narrow
- Running HDMI over long distances isn’t trivial
- Getting HDMI video into OBS
- USB capture cards
- Converts HDMI input for the computer via a USB port
- One per camera
- Same USB bandwidth issues as with USB webcams
- Can be inexpensive (as little as $10-$15 each), but a name-brand model at a slightly higher price can be worth it
- Internal capture cards
- Provide HDMI input for a set number of cameras
- Goes in a PCI Express slot in your desktop computer
- Could go into an external PCI-E enclosure if your laptop supports it
- No USB bandwidth concerns
- NDI Encoder
- Converts HDMI input to NDI
- Enables you to run from the encoder box to the computer with ethernet in place of long HDMI cables
- Can be PoE powered
- One example is the ZowieBox, $185
- USB capture cards
- Pros
- SDI Cameras
- Serial Digital Interface is the broadcast standard for digital video
- Uses coaxial cables with BNC connectors
- Works over long distances
- Long cables are cheaper than other video cables, though not as cheap as network cables
- Unlike NDI, needs a separate power cable
- Because they’re professional grade and broadcast quality, they’re expensive
- Requires external capture cards like HDMI cameras do, but at a higher cost
Camera Mounting & Placement
Mounting cameras
- Most cameras will have built-in tripod screw mounts
- You’ll probably need/want to go taller than the average tripod
- Depends on the camera’s field of view and the size of the field (e.g., IQ vs V5), and whether the field is elevated or on the ground
- “Light stand” is a good search term to use on Amazon.com; they’re like tripods but taller
- Weighing down the base of the tripod with sand bags is a good idea for stability if you need to go super-tall and/or have a heavy camera
- A “magic arm” has flexible pivot joints and is handy for mounting cameras at odd angles or to other objects; they have standard tripod screws on each end, so you can mount them between a camera and a clamp
Camera location/placement
- Audience side of the field is best
- Doesn’t usually have teams or volunteers standing there during the match
- This is the view the audience is used to
- But this means longer cable runs, so the the back side of the field next to the head referee is a decent compromise
- Make sure the entire field is in the shot!
- Also make sure the Competition Portal graphics won’t obscure parts of the field
- The camera position should not interfere with the flight area for the drones or provide a competitive advantage if there are areas that are intentionally hidden from view for the pilots.
- Keep things a few feet back from the field so there’s still room for teams and volunteers to walk around the field
- Importance of this varies from game to game
Equipment and Setup for Audio
Overview
Let’s take a look at a basic audio setup for an event, starting with a variety of audio sources. We’ve got one or more microphones for our MCs to talk into; the RECF Competition Portal is going to generate sounds that we want the audience and teams to hear, like the start and end of the match; and maybe we want some music to play between matches or in the background.
All of those will go into our audio mixer, which will mix the relative volumes of all of those sources so they sound good.
The audio mixer will send that balanced, mixed sound out to a couple of places: the speakers in the venue so the audience and teams can hear it, and OBS on the stream computer so it’s added to the live stream.
General Notes about Audio for Live Streams
- Don’t rely solely on the venue’s PA system; you might be able to use their mic, mixer, and/or speakers, but what we need for live streaming is more complicated than just making announcements in the gym.
- Set up and test everything before the event!
Audio: Mixer
- Requirements
- XLR inputs for as many mics as you need
- Stereo input(s) for field sounds and music
- Output to speakers (XLR or ¼”, depending on your speakers)
- Second output to OBS (¼” or USB, depending on your mixer)
- Could be labeled “Control Room”/”CR”, “Monitor”, “AUX”, or headphone out
- It’s nice to have a separate volume control for this output
- Example: Mackie 802VLZ4, $220
Audio: Microphones
- Wired
- Cheap
- Reliable
- Wireless
- No long cable to trip over
- Best to stick to known brands with good reviews
- Best to have a wired mic as a backup in case of issues
Audio: Speakers
- You might be able to use the venue’s existing speakers
- Look for XLR jacks in the wall or floor, and coordinate with venue staff as needed
- Test them before the event to make sure they work
- Watch for volume; sometimes wall jacks are meant for a mic and there’s another mixer or amp between the jack and the speakers
- If you’re considering purchasing speakers, “PA speakers” is a good search term
- Wide variety of models, sizes, power levels, and costs
Audio: PA Kits
- Pre-packaged “PA Kits” can be a good option
- Often includes a couple of speakers and a mixer that snap together into a portable form factor
- Some also come with mics and mic stands
- Usually designed to be portable
- Make sure the mixer has all the features you need
Audio: Music and RECF Competition Portal Sounds
- It’s best if these come from two separate sources so they’re different channels on the mixer, but they *can* come from the same computer
- Adjust relative volumes of music and field sounds in software
- If you’re going to play music over a stream, it must be appropriately-licensed or your stream will get muted, stopped, or removed from the archive
- One recommended source: pretzel.rocks has an adequate free tier; paid tier gives you access to more playlists
- Getting audio into OBS
- Desktop computer may already have a sound input jack
- If not (laptops, etc.), use a USB sound card
Works Cited
The information in this article is from one of our community volunteers, John Holbrook from the West Virginia Robotics Alliance, and is used here with his permission.
The West Virginia Robotics Alliance supports robotics events for many different robotics programs across West Virginia, running 30-40 events in a typical year in a wide range of venues. They’ve been livestreaming events for a number of years now, and began with the West Virginia state championships in 2018. In the 2021 season they ran a number of remote skills only events, and expanded their livestreaming capabilities to all events when in-person events resumed in 2022. They’ve now run more than one hundred livestreams, which are available on their YouTube channel. You can learn more about the West Virginia Robotics Alliance at their website: wvrobot.org.