Hudl Replay Networking Information
Hudl Replay gives coaches and athletes the ability to review and stream video of the latest plays instantly on the Replay Reviewing Device. The video source can be via a feed from the broadcast cameras, broadcast truck or a team supplied camera.
Hudl Replay System Components
Hudl Replay works with two or more devices on the same network to record video, then stream it along with tagged data to reviewers at the bench or in the coaches box. The Hudl Sportscode MacBook records the video, creates and controls the Replay Session and allows iPads running Hudl Replay to connect. Hudl Replay downloads video streams and accompanying data locally for playback and review.
The rest of this document is intended to inform IT Directors, IT Staff and System Administrators of stadium and arena enterprise networks on how Hudl Replay devices communicate to one another over a network. This document assumes that the reader is already familiar with networking concepts, such as those described in Apple’s Networking Overview and Networking Concepts documents.
Basic Network Setup
Network Diagram Example
This network diagram example outlines the basics of how Hudl Replay devices will connect to Hudl Sportscode in a professional arena (or stadium) network:
The video is encoded on the Hudl Sportscode MacBook according to a capture preset in Sportscode. Minimum bandwidth recommended for each device is 10Mbps or 1.15x the recorded video’s bitrate, whichever is higher.
If the available bandwidth lowers during a stream, the video will struggle to keep up and a “loading spinner” will be displayed on the Hudl Replay app.
The best way to add a Hudl Replay system to an enterprise network is to dedicate a virtual local area network (VLAN) for all of the devices. This VLAN should be an isolated network and all of the devices should be on a single VLAN. If you have an enterprise network, your IT staff will be familiar with this and can help set it up.
Replay works with both a wired and wireless network. If you decide to use a Wireless network then we have specific network setups you should use to ensure a stable connection during the game.
Establishing a Connection
By default, Hudl Replay discovers Hudl Sportscode through zero-configuration networking. Hudl Replay devices can browse through the network to discover each other and exchange the IP addresses to start the communication needed without any type of setup. The techniques used to do this discovery are Bonjour (Bonjour Zero Config Networking), DNS-SD (DNS Service Discovery) and mDNS (Multicast DNS).
DNS-SD is a mechanism that allows clients to discover a list of named instances of a desired service using standard DNS queries. Together with mDNS, DNS-SD provides this zero-configuration discovery between Hudl Replay and Hudl Sportscode.
In order for DNS-SD to discover other devices, it needs to be on the same VLAN and subnet as these devices. Additionally, Multicast must be enabled.
Hudl Sportscode devices will advertise an mDNS service on port 16123. Hudl Replay devices will pick up these services and initiate a websocket connection between them to exchange further information. It will also execute regular HTTP requests.
As an alternative to the zero-configuration setup, there is a Hudl Replay feature that allows a manual connection to be established between Hudl Replay and Hudl Sportscode. All you need to do is enter the IP address of the Hudl Sportscode MacBook and it will make a direct connection to the endpoint on port 16123.
An internet connection is not required to use Hudl Replay on a regular basis, but it is required during initial setup or to obtain product updates from the App Store. For setting up, the internet connection is required to authenticate the Replay Device’s license. Once authenticated, the license will stay persisted on the Replay Device for 52 weeks.
Hudl Replay supports offline playback, which means it can be disconnected from the network and it can continue to play back locally downloaded video. Upon reconnecting to the network it will download any video it has missed in the interim.
Hudl Sportscode uses HLS to describe the video it transmits to Hudl Replay devices, for which it spins up a web server on the Hudl Sportscode MacBook. This web server can run on any port above 1024 and it will automatically pick an available port. Which port it will take is not guaranteed.
Make sure only 1 network interface is active on both the Hudl Replay iPad as well as the Hudl Sportscode MacBook. Specifically: for the duration of the session you should not switch between WiFi and Ethernet, although it is okay to lose connection altogether.
Hudl Replay is compatible with the following iPad devices:
- iOS 11 or newer
- Hudl Replay iOS app from Apple App Store
Read more about Replay Hardware Recommendations.