self.startRunning이 제대로 작동하지 않습니다.

Question

현재 카메라를 사용하여 초당 15 프레임을 30 초 (총 450 프레임) 캡처하는 iOS 애플리케이션을 만들고 있습니다. 문제는 [self.session startRunning] (제공된 코드의 마지막 줄)이 작동하지 않는 것입니다. 캡쳐해야하는 450 프레임 각각의 평균 적색 값을 취하기 위해 색상이라고하는 배열을 설정했기 때문에 이것을 말합니다. 그러나 탐지를 시작하고 중지 한 후에도 배열은 비어 있습니다. 내가 뭘 놓치고 있니?

#import "ViewController.h" 
#import <AVFoundation/AVFoundation.h> 

@interface ViewController() 

@property (nonatomic, strong) AVCaptureSession *session; 
@property (nonatomic, strong) NSMutableArray *hues; 

@end 

const int SECONDS = 15; 
const int FPS = 30; 

@implementation ViewController 

- (void)viewDidLoad 
{ 
[super viewDidLoad]; 

self.hues = [[NSMutableArray alloc] init]; // initiate things (from old code) 
self.session = [[AVCaptureSession alloc] init]; 
self.session.sessionPreset = AVCaptureSessionPresetLow; 

NSInteger numberOfFramesCaptured = self.hues.count; 

// initialize the session with proper settings (from docs) 

NSError *error = nil; 

AVCaptureDevice *captureDevice; // initialize captureDevice and input, and add input (from old code) 
AVCaptureDeviceInput *videoInput = [[AVCaptureDeviceInput alloc] initWithDevice:captureDevice error:&error]; 
if ([self.session canAddInput:videoInput]) 
{ // fails 
    [self.session addInput:videoInput]; 
} 

// find the max fps we can get from the given device (from old code) 
AVCaptureDeviceFormat *currentFormat = [captureDevice activeFormat]; 

for (AVCaptureDeviceFormat *format in captureDevice.formats) // executes twice 
{ // skips all of this 
    NSArray *ranges = format.videoSupportedFrameRateRanges; 
    AVFrameRateRange *frameRates = ranges[0]; 

    // find the lowest resolution format at the frame rate we want (from old code) 
    if (frameRates.maxFrameRate == FPS && (!currentFormat || (CMVideoFormatDescriptionGetDimensions(format.formatDescription).width < CMVideoFormatDescriptionGetDimensions(currentFormat.formatDescription).width && CMVideoFormatDescriptionGetDimensions(format.formatDescription).height < CMVideoFormatDescriptionGetDimensions(currentFormat.formatDescription).height))) 
    { 
     currentFormat = format; 
    } 
} 

// tell the device to use the max frame rate (from old code) 
[captureDevice lockForConfiguration:nil]; 
captureDevice.torchMode = AVCaptureTorchModeOn; 
captureDevice.activeFormat = currentFormat; 
captureDevice.activeVideoMinFrameDuration = CMTimeMake(1, FPS); 
captureDevice.activeVideoMaxFrameDuration = CMTimeMake(1, FPS); 
[captureDevice unlockForConfiguration]; 

// set the output (from old code) 
AVCaptureVideoDataOutput *videoOutput = [[AVCaptureVideoDataOutput alloc] init]; 

// create a queue to run the capture on (from old code) 
dispatch_queue_t queue = dispatch_queue_create("queue", NULL); 

// setup our delegate (from old code) 
[videoOutput setSampleBufferDelegate:self queue:queue]; 

// configure the pixel format (from old code) 
videoOutput.videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithUnsignedInt:kCVPixelFormatType_32BGRA], (id)kCVPixelBufferPixelFormatTypeKey, nil]; 
videoOutput.alwaysDiscardsLateVideoFrames = NO; 

[self.session addOutput:videoOutput]; 

// start the video session 
[self.session startRunning]; // PROBLEM OCCURS HERE 

Answer 1

코드에 AVCaptureDevice *captureDevice;이 초기화되지 않았습니다.