5

ボタンが押されたときなど、特定のインスタンスで画像をキャプチャしたい。しかし、ビデオのプレビュー画面を表示したくありません。このシナリオでは、captureStillImageAsynchronouslyFromConnection を使用する必要があると思います。現在、ビデオプレビューを表示すると画像をキャプチャできます。ただし、プレビューを表示するコードを削除すると、アプリがクラッシュし、次の出力が表示されます。

2012-04-07 11:25:54.898 imCapWOPreview[748:707] *** キャッチされていない例外 'NSInvalidArgumentException' によるアプリの終了: '*** -[AVCaptureStillImageOutput captureStillImageAsynchronouslyFromConnection:completionHandler:] - 非アクティブ/無効な接続が渡されました。 ' *** First throw call stack: (0x336ee8bf 0x301e21e5 0x3697c35d 0x34187 0x33648435 0x310949eb 0x310949a7 0x31094985 0x310946f5 0x3109502d 0x3109350f 0x31092f01 0x310794ed 0x31078d2d 0x37db7df3 0x336c2553 0x336c24f5 0x336c1343 0x336444dd 0x336443a5 0x37db6fcd 0x310a7743 0x33887 0x3382c) terminate called throwing an exception(lldb)

だからここに私の実装があります：

BIDViewController.h:

#import <UIKit/UIKit.h>
#import <AVFoundation/AVFoundation.h>

@interface BIDViewController : UIViewController
{
    AVCaptureStillImageOutput *stillImageOutput;
}
@property (strong, nonatomic) IBOutlet UIView *videoPreview;
- (IBAction)doCap:(id)sender;

@end

BIDViewController.m 内の関連スタッフ:

#import "BIDViewController.h"

@interface BIDViewController ()

@end

@implementation BIDViewController
@synthesize capturedIm;
@synthesize videoPreview;

- (void)viewDidLoad
{
[super viewDidLoad];
[self setupAVCapture];
}

- (BOOL)setupAVCapture
{
NSError *error = nil;

AVCaptureSession *session = [AVCaptureSession new];
[session setSessionPreset:AVCaptureSessionPresetHigh];

/*
AVCaptureVideoPreviewLayer *captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
captureVideoPreviewLayer.frame = self.videoPreview.bounds;
[self.videoPreview.layer addSublayer:captureVideoPreviewLayer];    
 */

// Select a video device, make an input
AVCaptureDevice *backCamera = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:backCamera error:&error];
if (error)
    return NO;
if ([session canAddInput:input])
    [session addInput:input];

// Make a still image output
stillImageOutput = [AVCaptureStillImageOutput new];
NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys: AVVideoCodecJPEG, AVVideoCodecKey, nil];
[stillImageOutput setOutputSettings:outputSettings];    
if ([session canAddOutput:stillImageOutput])
    [session addOutput:stillImageOutput];

[session startRunning];

return YES;
}

- (IBAction)doCap:(id)sender {
AVCaptureConnection *videoConnection = nil;
for (AVCaptureConnection *connection in stillImageOutput.connections)
{
    for (AVCaptureInputPort *port in [connection inputPorts])
    {
        if ([[port mediaType] isEqual:AVMediaTypeVideo] )
        {
            videoConnection = connection;
            break;
        }
    }
    if (videoConnection) { break; }
}

[stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection 
  completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *__strong error) {
      // Do something with the captured image
  }];

}

上記のコードでは、doCap が呼び出されると、クラッシュが発生します。一方、 setupAVCapture 関数で次のコメントを削除すると、

/*
AVCaptureVideoPreviewLayer *captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
captureVideoPreviewLayer.frame = self.videoPreview.bounds;
[self.videoPreview.layer addSublayer:captureVideoPreviewLayer];    
 */

その後、問題なく動作します。

要約すると、私の質問は、プレビューを表示せずに制御されたインスタンスで画像をキャプチャするにはどうすればよいですか?

4

3 に答える 3

8

次のコードを使用して、前面カメラ (利用可能な場合) からキャプチャするか、背面カメラを使用します。私のiPhone 4Sでうまく動作します。

-(void)viewDidLoad{

    AVCaptureSession *session = [[AVCaptureSession alloc] init];
    session.sessionPreset = AVCaptureSessionPresetMedium;

    AVCaptureDevice *device = [self frontFacingCameraIfAvailable];

    NSError *error = nil;
    AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];
    if (!input) {
        // Handle the error appropriately.
        NSLog(@"ERROR: trying to open camera: %@", error);
    }
    [session addInput:input];

//stillImageOutput is a global variable in .h file: "AVCaptureStillImageOutput *stillImageOutput;"
    stillImageOutput = [[AVCaptureStillImageOutput alloc] init];
    NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys: AVVideoCodecJPEG, AVVideoCodecKey, nil];
    [stillImageOutput setOutputSettings:outputSettings];

    [session addOutput:stillImageOutput];

    [session startRunning];
}

-(AVCaptureDevice *)frontFacingCameraIfAvailable{

    NSArray *videoDevices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
    AVCaptureDevice *captureDevice = nil;

    for (AVCaptureDevice *device in videoDevices){

        if (device.position == AVCaptureDevicePositionFront){

            captureDevice = device;
            break;
        }
    }

    //  couldn't find one on the front, so just get the default video device.
    if (!captureDevice){

        captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    }

    return captureDevice;
}

-(IBAction)captureNow{

    AVCaptureConnection *videoConnection = nil;
    for (AVCaptureConnection *connection in stillImageOutput.connections){
        for (AVCaptureInputPort *port in [connection inputPorts]){

            if ([[port mediaType] isEqual:AVMediaTypeVideo]){

                videoConnection = connection;
                break;
            }
        }
        if (videoConnection) { 
           break; 
        }
    }

    NSLog(@"about to request a capture from: %@", stillImageOutput);
    [stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler: ^(CMSampleBufferRef imageSampleBuffer, NSError *error){

         CFDictionaryRef exifAttachments = CMGetAttachment( imageSampleBuffer, kCGImagePropertyExifDictionary, NULL);
         if (exifAttachments){

            // Do something with the attachments if you want to. 
            NSLog(@"attachements: %@", exifAttachments);
        }
        else
            NSLog(@"no attachments");

        NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageSampleBuffer];
        UIImage *image = [[UIImage alloc] initWithData:imageData];

        self.vImage.image = image;
    }];
}
于 2012-04-15T06:46:08.947 に答える