Hello, I am trying to capture screen recording ( output.mp4 ) using ScreenCaptureKit and also the mouse positions during the recording ( mouse.json ). The recording and the mouse positions ( tracked based on mouse movements events only ) needs to be perfectly synced in order to add effects in post editing.
I started off by using the await stream?.startCapture() and after that starting my mouse tracking function :-
try await captureEngine.startCapture(configuration: config, filter: filter, recordingOutput: recordingOutput)
let captureStartTime = Date()
mouseTracker?.startTracking(with: captureStartTime)
But every time I tested, there is a clear inconsistency in sync between the recorded video and the recorded mouse positions.
The only thing I want is to know when exactly does the recording "actually" started so that I can start the mouse capture at that same time, and thus I tried using the Delegates, but being able to set them up perfectly.
import Foundation
import AVFAudio
import ScreenCaptureKit
import OSLog
import Combine
class CaptureEngine: NSObject, @unchecked Sendable {
private let logger = Logger()
private(set) var stream: SCStream?
private var streamOutput: CaptureEngineStreamOutput?
private var recordingOutput: SCRecordingOutput?
private let videoSampleBufferQueue = DispatchQueue(label: "com.francestudio.phia.VideoSampleBufferQueue")
private let audioSampleBufferQueue = DispatchQueue(label: "com.francestudio.phia.AudioSampleBufferQueue")
private let micSampleBufferQueue = DispatchQueue(label: "com.francestudio.phia.MicSampleBufferQueue")
func startCapture(configuration: SCStreamConfiguration, filter: SCContentFilter, recordingOutput: SCRecordingOutput) async throws {
// Create the stream output delegate.
let streamOutput = CaptureEngineStreamOutput()
self.streamOutput = streamOutput
do {
stream = SCStream(filter: filter, configuration: configuration, delegate: streamOutput)
try stream?.addStreamOutput(streamOutput, type: .screen, sampleHandlerQueue: videoSampleBufferQueue)
try stream?.addStreamOutput(streamOutput, type: .audio, sampleHandlerQueue: audioSampleBufferQueue)
try stream?.addStreamOutput(streamOutput, type: .microphone, sampleHandlerQueue: micSampleBufferQueue)
self.recordingOutput = recordingOutput
recordingOutput.delegate = self
try stream?.addRecordingOutput(recordingOutput)
try await stream?.startCapture()
} catch {
logger.error("Failed to start capture: \(error.localizedDescription)")
throw error
}
}
func stopCapture() async throws {
do {
try await stream?.stopCapture()
} catch {
logger.error("Failed to stop capture: \(error.localizedDescription)")
throw error
}
}
func update(configuration: SCStreamConfiguration, filter: SCContentFilter) async {
do {
try await stream?.updateConfiguration(configuration)
try await stream?.updateContentFilter(filter)
} catch {
logger.error("Failed to update the stream session: \(String(describing: error))")
}
}
func stopRecordingOutputForStream(_ recordingOutput: SCRecordingOutput) throws {
try self.stream?.removeRecordingOutput(recordingOutput)
}
}
// MARK: - SCRecordingOutputDelegate
extension CaptureEngine: SCRecordingOutputDelegate {
func recordingOutputDidStartRecording(_ recordingOutput: SCRecordingOutput) {
let startTime = Date()
logger.info("Recording output did start recording \(startTime)")
}
func recordingOutputDidFinishRecording(_ recordingOutput: SCRecordingOutput) {
logger.info("Recording output did finish recording")
}
func recordingOutput(_ recordingOutput: SCRecordingOutput, didFailWithError error: any Error) {
logger.error("Recording output failed with error: \(error.localizedDescription)")
}
}
private class CaptureEngineStreamOutput: NSObject, SCStreamOutput, SCStreamDelegate {
private let logger = Logger()
override init() {
super.init()
}
func stream(_ stream: SCStream, didOutputSampleBuffer sampleBuffer: CMSampleBuffer, of outputType: SCStreamOutputType) {
guard sampleBuffer.isValid else { return }
switch outputType {
case .screen:
break
case .audio:
break
case .microphone:
break
@unknown default:
logger.error("Encountered unknown stream output type:")
}
}
func stream(_ stream: SCStream, didStopWithError error: Error) {
logger.error("Stream stopped with error: \(error.localizedDescription)")
}
}
I am getting error
Value of type 'SCRecordingOutput' has no member 'delegate'
Even though I am targeting macOs 15+ ( macOs 26 actually ) and macOs only.
What is the best way to achieving the desired result? Is there any other / better way to do it?
