fix(camera): harden capture pipeline

apps/ios/Sources/Camera/CameraController.swift

@@ -66,6 +66,7 @@ actor CameraController {
 
         session.startRunning()
         defer { session.stopRunning() }
+        await Self.warmUpCaptureSession()
 
         let settings: AVCapturePhotoSettings = {
             if output.availablePhotoCodecTypes.contains(.jpeg) {
@@ -144,6 +145,7 @@ actor CameraController {
 
         session.startRunning()
         defer { session.stopRunning() }
+        await Self.warmUpCaptureSession()
 
         let movURL = FileManager.default.temporaryDirectory
             .appendingPathComponent("clawdis-camera-\(UUID().uuidString).mov")
@@ -217,7 +219,7 @@ actor CameraController {
 
     private nonisolated static func exportToMP4(inputURL: URL, outputURL: URL) async throws {
         let asset = AVURLAsset(url: inputURL)
-        guard let exporter = AVAssetExportSession(asset: asset, presetName: AVAssetExportPresetHighestQuality) else {
+        guard let exporter = AVAssetExportSession(asset: asset, presetName: AVAssetExportPresetMediumQuality) else {
             throw CameraError.exportFailed("Failed to create export session")
         }
         exporter.shouldOptimizeForNetworkUse = true
@@ -233,22 +235,29 @@ actor CameraController {
             exporter.outputURL = outputURL
             exporter.outputFileType = .mp4
 
-            try await withCheckedThrowingContinuation(isolation: nil) { cont in
+            try await withCheckedThrowingContinuation(isolation: nil) { (cont: CheckedContinuation<Void, Error>) in
                 exporter.exportAsynchronously {
-                    switch exporter.status {
+                    cont.resume(returning: ())
-                    case .completed:
-                        cont.resume(returning: ())
-                    case .failed:
-                        cont.resume(throwing: exporter.error ?? CameraError.exportFailed("Export failed"))
-                    case .cancelled:
-                        cont.resume(throwing: CameraError.exportFailed("Export cancelled"))
-                    default:
-                        cont.resume(throwing: CameraError.exportFailed("Export did not complete"))
-                    }
                 }
             }
+
+            switch exporter.status {
+            case .completed:
+                return
+            case .failed:
+                throw CameraError.exportFailed(exporter.error?.localizedDescription ?? "export failed")
+            case .cancelled:
+                throw CameraError.exportFailed("export cancelled")
+            default:
+                throw CameraError.exportFailed("export did not complete")
+            }
         }
     }
+
+    private nonisolated static func warmUpCaptureSession() async {
+        // A short delay after `startRunning()` significantly reduces "blank first frame" captures on some devices.
+        try? await Task.sleep(nanoseconds: 150_000_000) // 150ms
+    }
 }
 
 private final class PhotoCaptureDelegate: NSObject, AVCapturePhotoCaptureDelegate {
@@ -278,6 +287,13 @@ private final class PhotoCaptureDelegate: NSObject, AVCapturePhotoCaptureDelegat
                 ]))
             return
         }
+        if data.isEmpty {
+            self.continuation.resume(
+                throwing: NSError(domain: "Camera", code: 2, userInfo: [
+                    NSLocalizedDescriptionKey: "photo data empty",
+                ]))
+            return
+        }
         self.continuation.resume(returning: data)
     }
 
@@ -311,6 +327,13 @@ private final class MovieFileDelegate: NSObject, AVCaptureFileOutputRecordingDel
         self.didResume = true
 
         if let error {
+            let ns = error as NSError
+            if ns.domain == AVFoundationErrorDomain,
+               ns.code == AVError.maximumDurationReached.rawValue
+            {
+                self.continuation.resume(returning: outputFileURL)
+                return
+            }
             self.continuation.resume(throwing: error)
             return
         }

apps/macos/Sources/Clawdis/CameraCaptureService.swift

@@ -61,6 +61,7 @@ actor CameraCaptureService {
 
         session.startRunning()
         defer { session.stopRunning() }
+        await Self.warmUpCaptureSession()
 
         let settings: AVCapturePhotoSettings = {
             if output.availablePhotoCodecTypes.contains(.jpeg) {
@@ -128,6 +129,7 @@ actor CameraCaptureService {
 
         session.startRunning()
         defer { session.stopRunning() }
+        await Self.warmUpCaptureSession()
 
         let tmpMovURL = FileManager.default.temporaryDirectory
             .appendingPathComponent("clawdis-camera-\(UUID().uuidString).mov")
@@ -243,10 +245,16 @@ actor CameraCaptureService {
             }
         }
     }
+
+    private nonisolated static func warmUpCaptureSession() async {
+        // A short delay after `startRunning()` significantly reduces "blank first frame" captures on some devices.
+        try? await Task.sleep(nanoseconds: 150_000_000) // 150ms
+    }
 }
 
 private final class PhotoCaptureDelegate: NSObject, AVCapturePhotoCaptureDelegate {
     private var cont: CheckedContinuation<Data, Error>?
+    private var didResume = false
 
     init(_ cont: CheckedContinuation<Data, Error>) {
         self.cont = cont
@@ -257,7 +265,8 @@ private final class PhotoCaptureDelegate: NSObject, AVCapturePhotoCaptureDelegat
         didFinishProcessingPhoto photo: AVCapturePhoto,
         error: Error?)
     {
-        guard let cont else { return }
+        guard !self.didResume, let cont else { return }
+        self.didResume = true
         self.cont = nil
         if let error {
             cont.resume(throwing: error)
@@ -267,8 +276,24 @@ private final class PhotoCaptureDelegate: NSObject, AVCapturePhotoCaptureDelegat
             cont.resume(throwing: CameraCaptureService.CameraError.captureFailed("No photo data"))
             return
         }
+        if data.isEmpty {
+            cont.resume(throwing: CameraCaptureService.CameraError.captureFailed("Photo data empty"))
+            return
+        }
         cont.resume(returning: data)
     }
+
+    func photoOutput(
+        _ output: AVCapturePhotoOutput,
+        didFinishCaptureFor resolvedSettings: AVCaptureResolvedPhotoSettings,
+        error: Error?)
+    {
+        guard let error else { return }
+        guard !self.didResume, let cont else { return }
+        self.didResume = true
+        self.cont = nil
+        cont.resume(throwing: error)
+    }
 }
 
 private final class MovieFileDelegate: NSObject, AVCaptureFileOutputRecordingDelegate {