Record Reaction

What You’ll Learn#

• How Reaction Mode differs from Standard and Dual Camera modes.
• How to launch the CE.SDK camera in Reaction Mode with a base video URL.
• How to record the user’s reaction (front camera + mic) while the base video plays.
• How to retrieve the reaction recording as a separate file.

When to Use It#

Choose Reaction Mode when you want users to capture their response to a video:

• Watch-along commentary, tutorials, or educational content
• Social media formats like reaction videos or duets
• Sports replays or event commentary where facial expressions matter
• Any scenario where the user’s reaction is the content

🚫 Not appropriate when:

• You only need a selfie-style recording → use Standard mode.
• You want to capture both front and back cameras simultaneously → use Dual Camera mode.
• You expect an auto-composited reaction + base video → Reaction Mode only records the reaction; you compose both in the editor.

Launching the Camera#

Initialize the IMGLYCamera in Reaction Mode with:

Camera(engineSettings, mode: .reaction(.vertical, video: baseURL, positionsSwapped: false)) { result in
  // Handle results here
}

• video: baseURL — the video to play back during recording
• positionsSwapped — swaps layout between playback and selfie preview (UI only)
• .vertical (or .horizontal) — how to lay out preview windows while recording

It’s also a good idea to lock the mode so that the user cannot switch out of reaction mode. Learn how to lock the mode in the Camera Configuration guide.

Retrieving the Recording#

When the recording finishes, you receive a .reaction(video: Recording, reaction: [Recording]) result with both the base and the reaction clips.

Here is a minimal code example that extracts the URL for each of the recordings:

Camera(engineSettings, mode: .reaction(.vertical, video: baseURL)) { result in
  switch result {
    case let .success(.reaction(video: base, reaction: reactions)):
      let baseVideoURL = base.videos.first?.url
      let reactionURL = reactions.first?.videos.first?.url
      print("Base video:", baseVideoURL as Any)
      print("Reaction video:", reactionURL as Any)

    case let .failure(error):
      print("Error:", error.localizedDescription)

    case let .success(.recording(recordings)):
      // This case is returned in Standard/Dual modes, not Reaction
      break
  }
}

You can learn more about the Recording struct in the Access Recordings guide . The reaction URL points to the Caches directory on the device. Be sure to copy it somewhere if you want to save it long-term.

Here is a simple helper function to copy a file to the Documents directory and return the URL of the new file location.

func persistFile(from sourceURL: URL, fileName: String) throws -> URL {
  let docs = try FileManager.default.url(for: .documentDirectory,
                                         in: .userDomainMask,
                                         appropriateFor: nil,
                                         create: true)
  let dest = docs.appendingPathComponent(fileName)
  if FileManager.default.fileExists(atPath: dest.path) {
    try FileManager.default.removeItem(at: dest)
  }
  try FileManager.default.copyItem(at: sourceURL, to: dest)
  return dest
}

The video previews are cropped to fit the screen, but the Recording struct contains full-screen data. The reaction video starts at time 0 of the base video. If the user pauses, both the base and the reaction videos will pause to preserve the time sync.

Troubleshooting#

❌ Reaction Video is Incomplete

When the user pauses and restarts the recording, the camera will create a new file for each segment. Process the array of recordings.

❌ Audio Echo

The base video’s audio may be picked up by the mic. Lower preview volume or suggest headphones.

Next Steps#

Reaction Mode is a powerful way to create engaging, social-friendly content. By combining playback and live recording, your users can produce watch-along or commentary videos with minimal setup. Continue exploring with these guides:

• Learn how to integrate the IMGLY Camera into your project.
• Configure the UI and other properties of the camera.
• Learn how to retrieve and manage recordings .