Uplift Capture is a cloud-connected mobile app that pairs and keeps two iOS devices in sync in order to capture time-synced video. All of this means there are a number of considerations when it comes to device connectivity. This article will explain the methods and the connection requirements Capture has in order to function correctly.

As of the the most recent version (February 2024), Uplift Capture now supports opening the app and starting and running a capture session even without an internet connection. Whenever possible, it’s still recommended that you run Uplift capture while connected to a strong wifi network, since that will ensure you have the most up-to-date lists of movements and athletes and automatically upload videos for processing.

When you are in an environment where the devices are connected to a network, because both devices need to see each other to pair, both devices need to be connected to the same network (see all best practices here).

If you choose to run Uplift Capture in an environment where there is no network connection, you will be able to capture, but you'll need to reconnect both devices to the internet once it's available to upload the videos for processing. For all instruction and considerations for offline captures, read this article.

Aside from connecting to the Uplift cloud, Capture also requires that both mobile devices are paired with one another, and that they stay in constant sync so that the videos captured on each devices can be used to generate full 3d data. Below we’ll explain how Capture pairs and then syncs both devices.

Uplift Capture uses Apple’s Multipeer Connectivity technology for the primary device to find and pair to the secondary device. This is essentially the same technology used by services like Air Drop to discover and connect with nearby devices.

Because entering pairing mode requires that one device is “searching” and the other is “discoverable”, do not enter pairing mode on both devices at the same time. The device that initiates pairing will become the Primary device, and the one that gets paired with will be Secondary.

Pairing enables the two devices to send messages back and forth to one another. These include the primary telling the secondary to start or stop recording, that the recording mode has been changed, one device letting the other know it has low battery or is getting hot, and other important information.

One of the most important reasons for device pairing is to keep the devices in sync.

By default, Capture uses a peer-to-peer (P2P) approach to syncing the two devices.

This means that each device pings the other constantly (except in the midst of recording a clip) to communicate the local clock time on each device. This clock time is used to calculate an offset between the two devices at the time recording starts, so that when both videos are uploaded to the cloud, they’re perfectly time-synced during processing.

While the devices should remain paired as long as they’re in range and in use, there are some cases when device pairing drops. This can happen for a number of reasons, including radio interference, the app or device being idle for long enough that iOS severs the connection, or some other process in iOS causing connection to drop. In these cases, as long as both devices are still in range with the wifi radio toggled on, you should be able to repair quickly and easily.