AVCapturePhotoOutput未返回正确的图像

Question

我在应用程序中的要求是在不预览UIImagePickerController的情况下捕获图像，因此我使用了以下代码来捕获图像而不呈现相同的图像。

- (void)clickImage
{
    AVCaptureDevice *rearCamera = [self checkIfRearCameraAvailable];

    if (rearCamera != nil)
    {
        photoSession = [[AVCaptureSession alloc] init];

        NSError *error;
        AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:rearCamera error:&error];

        if (!error && [photoSession canAddInput:input])
        {
            [photoSession addInput:input];

            AVCapturePhotoOutput *output = [[AVCapturePhotoOutput alloc] init];


            if ([photoSession canAddOutput:output])
            {
                [photoSession addOutput:output];

                AVCaptureConnection *videoConnection = nil;

                for (AVCaptureConnection *connection in output.connections)
                {
                    for (AVCaptureInputPort *port in [connection inputPorts])
                    {
                        if ([[port mediaType] isEqual:AVMediaTypeVideo])
                        {
                            videoConnection = connection;
                            break;
                        }
                    }
                    if (videoConnection)
                    {
                        break;
                    }
                }

                if (videoConnection)
                {
                    [photoSession startRunning];

                    [output capturePhotoWithSettings:[AVCapturePhotoSettings photoSettings] delegate:self];
                }
            }
        }
    }
}

- (AVCaptureDevice *)checkIfRearCameraAvailable
{
    AVCaptureDevice *rearCamera;

    AVCaptureDeviceDiscoverySession *captureDeviceDiscoverySession =
    [AVCaptureDeviceDiscoverySession discoverySessionWithDeviceTypes:@[AVCaptureDeviceTypeBuiltInWideAngleCamera]
                                                           mediaType:AVMediaTypeVideo
                                                            position:AVCaptureDevicePositionBack];

    NSArray *allCameras = [captureDeviceDiscoverySession devices];


    for (int i = 0; i < allCameras.count; i++)
    {
        AVCaptureDevice *camera = [allCameras objectAtIndex:i];

        if (camera.position == AVCaptureDevicePositionBack)
        {
            rearCamera = camera;
        }
    }

    return rearCamera;
}

- (void)captureOutput:(AVCapturePhotoOutput *)output didFinishProcessingPhotoSampleBuffer:(CMSampleBufferRef)photoSampleBuffer previewPhotoSampleBuffer:(CMSampleBufferRef)previewPhotoSampleBuffer resolvedSettings:(AVCaptureResolvedPhotoSettings *)resolvedSettings bracketSettings:(AVCaptureBracketedStillImageSettings *)bracketSettings error:(NSError *)error
{
    if (error)
    {
        NSLog(@"error : %@", error.localizedDescription);
    }

    if (photoSampleBuffer)
    {
        NSData *data = [AVCapturePhotoOutput JPEGPhotoDataRepresentationForJPEGSampleBuffer:photoSampleBuffer
                                                                   previewPhotoSampleBuffer:previewPhotoSampleBuffer];
        UIImage *image = [UIImage imageWithData:data];

        _imgView.image = image;
    }
}

我已经使用上面的代码来捕获图像，但输出的图像正在返回，看起来像是在夜间模式或负片图像。

你能检查一下代码并纠正我的错误吗？

Answer 1

我在Apple开发人员网站上找到了以下示例代码：

https://developer.apple.com/library/content/samplecode/AVCam/Introduction/Intro.html#//apple_ref/doc/uid/DTS40010112

上面的示例代码有助于获得正确的图像。我也添加了这个答案，以寻求他人的帮助。