[IOS] Scanner starts slow after 4/5 times.

[rogierrietdijk]

The scanner starts slow after 4/5 times.

While i was debugging the app with de current source i see dat the addinput and addoutput by de avcapturesession gives the problems.

            var scanner = new ZXing.Mobile.MobileBarcodeScanner ();
        scanner.UseCustomOverlay = false;


        ZXing.Mobile.MobileBarcodeScanningOptions options = new ZXing.Mobile.MobileBarcodeScanningOptions();
        options.TryHarder = true;
        options.PossibleFormats.Add(ZXing.BarcodeFormat.QR_CODE);

        scanner.Scan(options).ContinueWith(t => {  

            if (t.Result != null) {
                Console.WriteLine ("Scanned Barcode: " + t.Result.Text);
                }
            } else {

            }
        });

[Redth]

Can you expand on what you mean by 'AddInput and AddOutput gives the problems'? Not sure what you mean. Also would appreciate you giving me a chance to help make this better before leaving such a negative review on the component store.

[rogierrietdijk]

Thnx for your quick response.

I dont now :-) Here below is the code.

-- session.AddOutput (metadataOutput); and session.AddInput (input);

bool SetupCaptureSession ()
{
// configure the capture session for low resolution, change this if your code
// can cope with more data or volume
session = new AVCaptureSession () {
SessionPreset = AVCaptureSession.Preset640x480,
};

        // create a device input and attach it to the session

// var captureDevice = AVCaptureDevice.DefaultDeviceWithMediaType (AVMediaType.Video);
AVCaptureDevice captureDevice = null;
var devices = AVCaptureDevice.DevicesWithMediaType(AVMediaType.Video);
foreach (var device in devices)
{
captureDevice = device;
if (options.UseFrontCameraIfAvailable.HasValue &&
options.UseFrontCameraIfAvailable.Value &&
device.Position == AVCaptureDevicePosition.Front)

                break; //Front camera successfully set
            else if (device.Position == AVCaptureDevicePosition.Back && (!options.UseFrontCameraIfAvailable.HasValue || !options.UseFrontCameraIfAvailable.Value))
                break; //Back camera succesfully set
        }
        if (captureDevice == null){
            Console.WriteLine ("No captureDevice - this won't work on the simulator, try a physical device");
            if (overlayView != null)
            {
                this.AddSubview (overlayView);
                this.BringSubviewToFront (overlayView);
            }
            return false;
        }

        var input = AVCaptureDeviceInput.FromDevice (captureDevice);
        if (input == null){
            Console.WriteLine ("No input - this won't work on the simulator, try a physical device");
            if (overlayView != null)
            {
                this.AddSubview (overlayView);
                this.BringSubviewToFront (overlayView);
            }               
            return false;
        }
        else
            session.AddInput (input);


        foundResult = false;
        //Detect barcodes with built in avcapture stuff
        AVCaptureMetadataOutput metadataOutput = new AVCaptureMetadataOutput();

        var dg = new CaptureDelegate (metaDataObjects =>
            {
                if (foundResult)
                    return;

                //Console.WriteLine("Found MetaData Objects");

                var mdo = metaDataObjects.FirstOrDefault();

                if (mdo == null)
                    return;

                var readableObj = mdo as AVMetadataMachineReadableCodeObject;

                if (readableObj == null)
                    return;

                foundResult = true;

                //Console.WriteLine("Barcode: " + readableObj.StringValue);

                var zxingFormat = ZXingBarcodeFormatFromAVCaptureBarcodeFormat(readableObj.Type.ToString());

                var rs = new ZXing.Result(readableObj.StringValue, null, null, zxingFormat);

                resultCallback(rs);
            });

        metadataOutput.SetDelegate (dg, MonoTouch.CoreFoundation.DispatchQueue.MainQueue);
        session.AddOutput (metadataOutput);

        //Setup barcode formats
        if (ScanningOptions.PossibleFormats != null && ScanningOptions.PossibleFormats.Count > 0)
        {
            var formats = new List<string> ();

            foreach (var f in ScanningOptions.PossibleFormats)
                formats.AddRange (AVCaptureBarcodeFormatFromZXingBarcodeFormat (f));

            metadataOutput.MetadataObjectTypes = (from f in formats.Distinct () select new NSString(f)).ToArray();
        }
        else
            metadataOutput.MetadataObjectTypes = metadataOutput.AvailableMetadataObjectTypes;





        previewLayer = new AVCaptureVideoPreviewLayer(session);

        //Framerate set here (15 fps)
        if (previewLayer.RespondsToSelector(new Selector("connection")))
            previewLayer.Connection.VideoMinFrameDuration = new CMTime(1, 10);

        previewLayer.LayerVideoGravity = AVLayerVideoGravity.ResizeAspectFill;
        previewLayer.Frame = this.Frame;
        previewLayer.Position = new PointF(this.Layer.Bounds.Width / 2, (this.Layer.Bounds.Height / 2));

        layerView = new UIView(this.Frame);
        layerView.AutoresizingMask = UIViewAutoresizing.FlexibleWidth | UIViewAutoresizing.FlexibleHeight;
        layerView.Layer.AddSublayer(previewLayer);

        this.AddSubview(layerView);

        ResizePreview(UIApplication.SharedApplication.StatusBarOrientation);

        if (overlayView != null)
        {
            this.AddSubview (overlayView);
            this.BringSubviewToFront (overlayView);

            //overlayView.LayoutSubviews ();
        }

        session.StartRunning ();

        Console.WriteLine ("RUNNING!!!");



        //output.AlwaysDiscardsLateVideoFrames = true;


        Console.WriteLine("SetupCamera Finished");

        //session.AddOutput (output);
        //session.StartRunning ();


        if (captureDevice.IsFocusModeSupported(AVCaptureFocusMode.ModeContinuousAutoFocus))
        {
            NSError err = null;
            if (captureDevice.LockForConfiguration(out err))
            {
                captureDevice.FocusMode = AVCaptureFocusMode.ModeContinuousAutoFocus;

                if (captureDevice.FocusPointOfInterestSupported)
                    captureDevice.FocusPointOfInterest = new PointF(0.5f, 0.5f);

                captureDevice.UnlockForConfiguration();
            }
            else
                Console.WriteLine("Failed to Lock for Config: " + err.Description);
        }

        return true;
    }

[rogierrietdijk]

This is in the ACCaptureScannerView.cs file from the MonoTouch.Sample app

[Redth]

It would be more helpful if you could share some results of profiling: http://docs.xamarin.com/guides/ios/deployment%2C_testing%2C_and_metrics/using_instruments_to_detect_native_leaks_using_markheap

[Redth]

For example, are there memory leaks you're encountering at the point it slows down, or generally high usage of memory? etc.

[rogierrietdijk]

I found it. the fix is to remove de input and output from the session in the StopScanning method.

session.RemoveOutput (session.Outputs [0]);
session.RemoveInput (session.Inputs [0]);

[Redth]

Great, I'll give this a try!

[djlsw]

Hi All,
I hope this helps someone else out there. With version 1.4.0, I was experiencing this same issue with the scanner locking up after 4-5 scans when using the OS7 built in AVCaptureSession MetadataObject barcode scanning.

I fixed my problem by adding the same code for suggested fix #71 to the StopScanning method in the AVCaptureView.cs file (found at 3f4267e). Once I did that, my problem went away.

Once again, thanks for the efforts on this project. They are greatly appreciated.

[brunnurs]

@Redth First, thanks for the effort you guys put in this project! It makes life for startups like we are a lot easier.

Unfortunately, I still experience the effect, that after a few scans, the scanner opens very slow.

Here some figures:

On 2nd opening:

2014-02-03 17:09:13.967 DralloTouch[618:60b] Starting to scan... 2014-02-03 17:09:14.017 DralloTouch[618:60b] ZXingScannerView.Setup() took 24.003 ms. 2014-02-03 17:09:14.023 DralloTouch[618:60b] StartScanning 2014-02-03 17:09:14.155 DralloTouch[618:e007] Decode Time: 1884 ms 2014-02-03 17:09:16.030 DralloTouch[618:60b] PERF: Alloc AVCaptureVideoPreviewLayer took 33.345 ms. 2014-02-03 17:09:16.049 DralloTouch[618:60b] PERF: ActiveVideoMinFrameDuration Took 2.5936 ms 2014-02-03 17:09:16.060 DralloTouch[618:60b] PERF: Setting up layers took 7.6259 ms 2014-02-03 17:09:18.485 DralloTouch[618:60b] PERF: session.StartRunning() took 2421.1751 ms 2014-02-03 17:09:18.498 DralloTouch[618:60b] PERF: SetupCamera Finished. Took 3.5815 ms. Thread started: #27 2014-02-03 17:09:19.280 DralloTouch[618:60b] PERF: Setup Focus in 3.6367 ms. 2014-02-03 17:09:19.288 DralloTouch[618:60b] PERF: StartScanning() Took 5294.4142 ms.

On 3rd opening:

2014-02-03 17:10:16.337 DralloTouch[618:60b] Starting to scan... 2014-02-03 17:10:16.402 DralloTouch[618:60b] ZXingScannerView.Setup() took 23.532 ms. 2014-02-03 17:10:16.415 DralloTouch[618:60b] StartScanning 2014-02-03 17:10:16.715 DralloTouch[618:ea27] Decode Time: 1481 ms 2014-02-03 17:10:27.353 DralloTouch[618:60b] PERF: Alloc AVCaptureVideoPreviewLayer took 91.823 ms. 2014-02-03 17:10:27.363 DralloTouch[618:60b] PERF: ActiveVideoMinFrameDuration Took 2.3172 ms 2014-02-03 17:10:27.386 DralloTouch[618:60b] PERF: Setting up layers took 18.7959 ms 2014-02-03 17:10:38.721 DralloTouch[618:60b] PERF: session.StartRunning() took 11325.0526 ms 2014-02-03 17:10:38.735 DralloTouch[618:60b] PERF: SetupCamera Finished. Took 2.7098 ms. Thread started: #36 2014-02-03 17:10:39.517 DralloTouch[618:60b] PERF: Setup Focus in 2.2247 ms. 2014-02-03 17:10:39.553 DralloTouch[618:60b] PERF: StartScanning() Took 23174.767 ms.

I'm using zxing.monotouch.dll V 0.12.0.0 and ZXing.Net.Mobile V 1.4.1.0 and I see that the commit 3f4267e is already included in this version.

So I'm a little baffled. Thanks for any help!

[brunnurs]

Update: I included the official V 1.4.0 version in the app and everything is working fine...

[mapo80]

Hi,

I've the same problem. After 4/5 times scanner starts very slowly. I'm using v.1.4.2 and I'm using an iPhone 5 on iOS 7.

Any solution? I've seen that fix suggested is included in verso 1.4.2

2014-03-10 19:14:12.525 PhotoShare[1053:60b] PERF: Setup Focus in 1,4683 ms.
2014-03-10 19:14:12.527 PhotoShare[1053:60b] PERF: StartScanning() Took 2772,0947 ms.
2014-03-10 19:14:13.670 PhotoShare[1053:60b] Stopping scan...
2014-03-10 19:14:15.424 PhotoShare[1053:7f03] Connected to the server
2014-03-10 19:14:15.936 PhotoShare[1053:60b] Starting to scan...
2014-03-10 19:14:15.944 PhotoShare[1053:60b] ZXingScannerView.Setup() took 5,282 ms.
2014-03-10 19:14:15.945 PhotoShare[1053:60b] StartScanning
2014-03-10 19:14:25.537 PhotoShare[1053:60b] PERF: Alloc AVCaptureVideoPreviewLayer took 11,132 ms.
2014-03-10 19:14:25.541 PhotoShare[1053:60b] PERF: ActiveVideoMinFrameDuration Took 2,0896 ms
2014-03-10 19:14:25.547 PhotoShare[1053:60b] PERF: Setting up layers took 3,8447 ms
2014-03-10 19:14:36.171 PhotoShare[1053:60b] PERF: session.StartRunning() took 10622,8122 ms
2014-03-10 19:14:36.173 PhotoShare[1053:60b] PERF: SetupCamera Finished. Took 0,7167 ms.
2014-03-10 19:14:36.920 PhotoShare[1053:60b] PERF: Setup Focus in 1,4963 ms.
2014-03-10 19:14:36.922 PhotoShare[1053:60b] PERF: StartScanning() Took 20982,9365 ms.

[rogierrietdijk]

In the file AVCaptureScannerView.cs change te method StopScanning() to the code below: (Remove output and inputs)

public void StopScanning()
{
if (stopped)
return;

        Console.WriteLine("Stopping...");

        if (session.Running) {

            session.StopRunning ();

            session.RemoveOutput (session.Outputs [0]);
            session.RemoveInput (session.Inputs [0]);
            session.Dispose ();
        }

        stopped = true;
    }

Rogier Rietdijk

Op 10 mrt. 2014, om 19:16 heeft mapo80 notifications@github.com het volgende geschreven:

Hi,

I've the same problem. After 4/5 times scanner starts very slowly. I'm using v.1.4.2 and I'm using an iPhone 5 on iOS 7.

Any solution? I've seen that fix suggested is included in verso 1.4.2

2014-03-10 19:14:12.525 PhotoShare[1053:60b] PERF: Setup Focus in 1,4683 ms.
2014-03-10 19:14:12.527 PhotoShare[1053:60b] PERF: StartScanning() Took 2772,0947 ms.
2014-03-10 19:14:13.670 PhotoShare[1053:60b] Stopping scan...
2014-03-10 19:14:15.424 PhotoShare[1053:7f03] Connected to the server
2014-03-10 19:14:15.936 PhotoShare[1053:60b] Starting to scan...
2014-03-10 19:14:15.944 PhotoShare[1053:60b] ZXingScannerView.Setup() took 5,282 ms.
2014-03-10 19:14:15.945 PhotoShare[1053:60b] StartScanning
2014-03-10 19:14:25.537 PhotoShare[1053:60b] PERF: Alloc AVCaptureVideoPreviewLayer took 11,132 ms.
2014-03-10 19:14:25.541 PhotoShare[1053:60b] PERF: ActiveVideoMinFrameDuration Took 2,0896 ms
2014-03-10 19:14:25.547 PhotoShare[1053:60b] PERF: Setting up layers took 3,8447 ms
2014-03-10 19:14:36.171 PhotoShare[1053:60b] PERF: session.StartRunning() took 10622,8122 ms
2014-03-10 19:14:36.173 PhotoShare[1053:60b] PERF: SetupCamera Finished. Took 0,7167 ms.
2014-03-10 19:14:36.920 PhotoShare[1053:60b] PERF: Setup Focus in 1,4963 ms.
2014-03-10 19:14:36.922 PhotoShare[1053:60b] PERF: StartScanning() Took 20982,9365 ms.

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