fixed #1209 AVCaptureSession startRunning] should be called from background thread.

Sources/Media/IOMixer.swift

@@ -19,6 +19,7 @@ protocol IOMixerDelegate: AnyObject {
     func mixer(_ mixer: IOMixer, sessionWasInterrupted session: AVCaptureSession, reason: AVCaptureSession.InterruptionReason)
     func mixer(_ mixer: IOMixer, sessionInterruptionEnded session: AVCaptureSession, reason: AVCaptureSession.InterruptionReason)
     #endif
+    func mixerSessionWillResume(_ mixer: IOMixer)
 }
 
 /// An object that mixies audio and video for streaming.
@@ -323,6 +324,11 @@ extension IOMixer: Running {
         isRunning.mutate { $0 = session.isRunning }
     }
 
+    func startCaptureSession() {
+        session.startRunning()
+        isRunning.mutate { $0 = session.isRunning }
+    }
+
     private func addSessionObservers(_ session: AVCaptureSession) {
         NotificationCenter.default.addObserver(self, selector: #selector(sessionRuntimeError(_:)), name: .AVCaptureSessionRuntimeError, object: session)
         #if os(iOS)
@@ -438,8 +444,7 @@ extension IOMixer: Running {
         guard isRunning.value && !session.isRunning else {
             return
         }
-        session.startRunning()
-        isRunning.mutate { $0 = session.isRunning }
+        delegate?.mixerSessionWillResume(self)
     }
 }
 #else

Sources/Net/NetStream.swift

@@ -40,7 +40,11 @@ open class NetStream: NSObject {
     private static let queueValue = UnsafeMutableRawPointer.allocate(byteCount: 1, alignment: 1)
 
     /// The mixer object.
-    public private(set) var mixer = IOMixer()
+    public private(set) lazy var mixer: IOMixer = {
+        let mixer = IOMixer()
+        mixer.delegate = self
+        return mixer
+    }()
     /// Specifies the delegate of the NetStream.
     public weak var delegate: (any NetStreamDelegate)?
 
@@ -282,6 +286,33 @@ open class NetStream: NSObject {
     }
 }
 
+extension NetStream: IOMixerDelegate {
+    // MARK: IOMixerDelegate
+    func mixer(_ mixer: IOMixer, didOutput video: CMSampleBuffer) {
+        delegate?.stream(self, didOutput: video)
+    }
+
+    func mixer(_ mixer: IOMixer, didOutput audio: AVAudioPCMBuffer, presentationTimeStamp: CMTime) {
+        delegate?.stream(self, didOutput: audio, presentationTimeStamp: presentationTimeStamp)
+    }
+
+    func mixerSessionWillResume(_ mixer: IOMixer) {
+        lockQueue.async {
+            mixer.startCaptureSession()
+        }
+    }
+
+    #if os(iOS)
+    func mixer(_ mixer: IOMixer, sessionWasInterrupted session: AVCaptureSession, reason: AVCaptureSession.InterruptionReason) {
+        delegate?.stream(self, sessionWasInterrupted: session, reason: reason)
+    }
+
+    func mixer(_ mixer: IOMixer, sessionInterruptionEnded session: AVCaptureSession, reason: AVCaptureSession.InterruptionReason) {
+        delegate?.stream(self, sessionInterruptionEnded: session, reason: reason)
+    }
+    #endif
+}
+
 extension NetStream: IOScreenCaptureUnitDelegate {
     // MARK: IOScreenCaptureUnitDelegate
     public func session(_ session: any IOScreenCaptureUnit, didOutput pixelBuffer: CVPixelBuffer, presentationTime: CMTime) {

Sources/RTMP/RTMPStream.swift

@@ -638,25 +638,3 @@ extension RTMPStream: RTMPMuxerDelegate {
         return delegate?.streamWillDropFrame(self) ?? false
     }
 }
-
-extension RTMPStream: IOMixerDelegate {
-    // MARK: IOMixerDelegate
-    func mixer(_ mixer: IOMixer, didOutput video: CMSampleBuffer) {
-        frameCount += 1
-        delegate?.stream(self, didOutput: video)
-    }
-
-    func mixer(_ mixer: IOMixer, didOutput audio: AVAudioPCMBuffer, presentationTimeStamp: CMTime) {
-        delegate?.stream(self, didOutput: audio, presentationTimeStamp: presentationTimeStamp)
-    }
-
-    #if os(iOS)
-    func mixer(_ mixer: IOMixer, sessionWasInterrupted session: AVCaptureSession, reason: AVCaptureSession.InterruptionReason) {
-        delegate?.stream(self, sessionWasInterrupted: session, reason: reason)
-    }
-
-    func mixer(_ mixer: IOMixer, sessionInterruptionEnded session: AVCaptureSession, reason: AVCaptureSession.InterruptionReason) {
-        delegate?.stream(self, sessionInterruptionEnded: session, reason: reason)
-    }
-    #endif
-}