I have a camera application which aims to take images as close to simultaneously as possible from the wide and ultra-wide cameras. The AVCaptureMultiCamSession is setup with manual connections. Note: we are not using builtInDualWideCamera with constituent photo delivery enabled since some features we use are not supported in that mode.
At the moment, we are manually trying to synchronize frames between the two cameras, but we would like to use the AVCaptureDataOutputSynchronizer to improve our results.
Is it possible to synchronize the wide and ultra-wide video outputs? All examples and docs that I've found show synchronization with video and depth, metadata, or audio, but not two video outputs.
From my testing, I've found that the dataOutputSynchronizer either fires with the wide video output, or the ultra video output, but never both (at least one is nil), suggesting that they are not being synchronized.
self.outputSync = AVCaptureDataOutputSynchronizer(dataOutputs: [wideCameraOutput, ultraCameraOutput])
outputSync.setDelegate(self, queue: .main)
...
func dataOutputSynchronizer(_ synchronizer: AVCaptureDataOutputSynchronizer, didOutput synchronizedDataCollection: AVCaptureSynchronizedDataCollection) {
guard let syncWideData: AVCaptureSynchronizedSampleBufferData = synchronizedDataCollection.synchronizedData(for: self.wideCameraOutput) as? AVCaptureSynchronizedSampleBufferData,
let syncedUltraData: AVCaptureSynchronizedSampleBufferData = synchronizedDataCollection.synchronizedData(for: self.ultraCameraOutput) as? AVCaptureSynchronizedSampleBufferData else {
return;
}
// either syncWideData or syncUltraData is always nil, so the guard condition never passes.
}