iOS二维码，条形码扫描问题

1.公司做一个二维码条形码扫描的项目，遇到二维码扫描很好识别，条形码扫描有点慢

解决办法：device放大焦距（完美解决）

 //获取摄像设备

    AVCaptureDevice * device = [AVCaptureDevicedefaultDeviceWithMediaType:AVMediaTypeVideo];

    //创建输入流

    AVCaptureDeviceInput * input = [AVCaptureDeviceInputdeviceInputWithDevice:device error:nil];

    //创建输出流

    AVCaptureMetadataOutput * output = [[AVCaptureMetadataOutputalloc]init];

    //设置代理在主线程里刷新

    [output setMetadataObjectsDelegate:selfqueue:dispatch_get_main_queue()];

    output.rectOfInterest = scanCrop;

//    [ output setRectOfInterest : CGRectMake (( 124 )/ ScreenHEI ,(( ScreenWHD - 220 )/ 2 )/ ScreenWHD , 220 / ScreenHEI , 220 / ScreenWHD )];

    //初始化链接对象

    session = [[AVCaptureSessionalloc]init];

    //高质量采集率

    [sessionsetSessionPreset:AVCaptureSessionPresetHigh];

    if (input) {

        [sessionaddInput:input];

    }

    if (output) {

        [sessionaddOutput:output];

        //设置扫码支持的编码格式(如下设置条形码和二维码兼容)

        NSMutableArray *a = [[NSMutableArrayalloc] init];

        if ([output.availableMetadataObjectTypescontainsObject:AVMetadataObjectTypeQRCode]) {

            [a addObject:AVMetadataObjectTypeQRCode];

        }

        if ([output.availableMetadataObjectTypescontainsObject:AVMetadataObjectTypeEAN13Code]) {

            [a addObject:AVMetadataObjectTypeEAN13Code];

        }

        if ([output.availableMetadataObjectTypescontainsObject:AVMetadataObjectTypeEAN8Code]) {

            [a addObject:AVMetadataObjectTypeEAN8Code];

        }

        if ([output.availableMetadataObjectTypescontainsObject:AVMetadataObjectTypeCode128Code]) {

            [a addObject:AVMetadataObjectTypeCode128Code];

        }

        output.metadataObjectTypes=a;

    }

    /*

     [ _output setRectOfInterest : CGRectMake (( 124 )/ ScreenHigh ,(( ScreenWidth - 220 )/ 2 )/ ScreenWidth , 220 / ScreenHigh , 220 / ScreenWidth )];

     */

    AVCaptureVideoPreviewLayer * layer = [AVCaptureVideoPreviewLayerlayerWithSession:session];

    layer.videoGravity=AVLayerVideoGravityResizeAspectFill;

    layer.frame = CGRectMake(0, 0, [UIScreenmainScreen].bounds.size.width, self.ScanReadView.frame.size.height);

    [self.ScanReadView.layerinsertSublayer:layer atIndex:0];

    [selfsetOverlayPickerView:self.ScanReadView];

    //放大焦距

    NSError *error = nil;

    [device lockForConfiguration:&error];

    if (device.activeFormat.videoMaxZoomFactor > 2) {

        device.videoZoomFactor = 2;

    }else{

        device.videoZoomFactor = device.activeFormat.videoMaxZoomFactor;

    }

    [device unlockForConfiguration];

    //开始捕获

    [sessionstartRunning];