I'm developing an iOS app using DockKit to control a motorized stand. I've noticed that as the zoom factor of the AVCaptureDevice increases, the stand's movement becomes increasingly erratic up and down, almost like a pendulum motion. I'm not sure why this is happening or how to fix it.
Here's a simplified version of my tracking logic:
func trackObject(_ boundingBox: CGRect, _ dockAccessory: DockAccessory) async throws {
guard let device = AVCaptureDevice.default(for: .video),
let input = try? AVCaptureDeviceInput(device: device) else {
fatalError("Camera not available")
}
let currentZoomFactor = device.videoZoomFactor
let dimensions = device.activeFormat.formatDescription.dimensions
let referenceDimensions = CGSize(width: CGFloat(dimensions.width), height: CGFloat(dimensions.height))
let intrinsics = calculateIntrinsics(for: device, currentZoom: Double(currentZoomFactor))
let deviceOrientation = UIDevice.current.orientation
let cameraOrientation: DockAccessory.CameraOrientation = {
switch deviceOrientation {
case .landscapeLeft: return .landscapeLeft
case .landscapeRight: return .landscapeRight
case .portrait: return .portrait
case .portraitUpsideDown: return .portraitUpsideDown
default: return .unknown
}
}()
let cameraInfo = DockAccessory.CameraInformation(
captureDevice: input.device.deviceType,
cameraPosition: input.device.position,
orientation: cameraOrientation,
cameraIntrinsics: useIntrinsics ? intrinsics : nil,
referenceDimensions: referenceDimensions
)
let observation = DockAccessory.Observation(
identifier: 0,
type: .object,
rect: boundingBox
)
let observations = [observation]
try await dockAccessory.track(observations, cameraInformation: cameraInfo)
}
func calculateIntrinsics(for device: AVCaptureDevice, currentZoom: Double) -> matrix_float3x3 {
let dimensions = CMVideoFormatDescriptionGetDimensions(device.activeFormat.formatDescription)
let width = Float(dimensions.width)
let height = Float(dimensions.height)
let diagonalPixels = sqrt(width * width + height * height)
let estimatedFocalLength = diagonalPixels * 0.8
let fx = Float(estimatedFocalLength) * Float(currentZoom)
let fy = fx
let cx = width / 2.0
let cy = height / 2.0
return matrix_float3x3(
SIMD3<Float>(fx, 0, cx),
SIMD3<Float>(0, fy, cy),
SIMD3<Float>(0, 0, 1)
)
}
I'm calling this function regularly (10-30 times per second) with updated bounding box information. The erratic movement seems to worsen as the zoom factor increases.
Questions:
Why might increasing the zoom factor cause this erratic movement?
I'm currently calculating camera intrinsics based on the current zoom factor. Is this approach correct, or should I be doing something differently?
Are there any other factors I should consider when using DockKit with a variable zoom?
Could the frequency of calls to trackRider (10-30 times per second) be contributing to the erratic movement? If so, what would be an optimal frequency?
Any insights or suggestions would be greatly appreciated. Thanks!
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Hello,
I‘m using DockKit within my SwiftUI Application with GetStream. Before updating to iOS 18 yesterday the custom Tracking using DockKit worked like a charm, but After updating it stopped working unexpectedly.
What‘s more curious: using the official GetStream Video Calls Application it works on iOS18 still, but Not within my Application. I can confirm, that my iPhone is still paired and I can receive logs about the current docking State and everything seems fine.
Any suggestions what I‘m missing here?
Struggling for weeks to publish a new update of my app, which includes the first-time submission of a subscription with auto-renewal. It's constantly being rejected due to the following issue:
We have started the review of your app, but we are still not able to continue because we cannot locate the in-app purchases within your app at this time.
Next Steps
To help us proceed with the review of your app, please reply to this message providing the steps for locating the in-app purchases in your app.
If you are restricting access to in-app purchases based on factors such as storefront or device configurations, please include this information in your reply along with steps to enable the in-app purchases for our review.
No further information is provided, no communication on the steps being taken by Apple. Additionally, I have already provided a comprehensive description during submission on how to access the In-App Purchase (IAP) as text and video.
What's kind of interesting: the app got rejected, but the related subscription is still in state "waiting for review".
Has anyone else experienced a similar issue?