iOS直接获取摄像头数据

需要添加的  Framework :CoreMedia, CoreVideo QuartzCore, AVFoundation 
MyAVController.h: 

#import <UIKit/UIKit.h> 
#import <AVFoundation/AVFoundation.h> 
#import <CoreGraphics/CoreGraphics.h> 
#import <CoreVideo/CoreVideo.h> 
#import <CoreMedia/CoreMedia.h> 

@interface MyAVController : UIViewController < 
AVCaptureVideoDataOutputSampleBufferDelegate> { 
    AVCaptureSession *_captureSession; 
    UIImageView *_imageView; 
    CALayer *_customLayer; 
    AVCaptureVideoPreviewLayer *_prevLayer; 
} 

@property (nonatomic, retain) AVCaptureSession *captureSession; 
@property (nonatomic, retain) UIImageView *imageView; 
@property (nonatomic, retain) CALayer *customLayer; 
@property (nonatomic, retain) AVCaptureVideoPreviewLayer *prevLayer; 
- (void)initCapture; 

@end 

MyAVController.m: 

#import "MyAVController.h" 

@implementation MyAVController 

@synthesize captureSession = _captureSession; 
@synthesize imageView = _imageView; 
@synthesize customLayer = _customLayer; 
@synthesize prevLayer = _prevLayer; 

#pragma mark - 
#pragma mark Initialization 
- (id)init { 
    self = [super init]; 
    if (self) { 
        self.imageView = nil; 
        self.prevLayer = nil; 
        self.customLayer = nil; 
    } 
    return self; 
} 

- (void)viewDidLoad { 
    [self initCapture]; 
} 

- (void)initCapture { 
    AVCaptureDeviceInput *captureInput = [AVCaptureDeviceInput 
                     deviceInputWithDevice:[AVCaptureDevice 
defaultDeviceWithMediaType:AVMediaTypeVideo]  error:nil]; 
    AVCaptureVideoDataOutput *captureOutput = [[AVCaptureVideoDataOutput alloc] 
init]; 
    captureOutput.alwaysDiscardsLateVideoFrames = YES; 
    //captureOutput.minFrameDuration = CMTimeMake(1, 10); 

    dispatch_queue_t queue; 
    queue = dispatch_queue_create("cameraQueue", NULL); 
    [captureOutput setSampleBufferDelegate:self queue:queue]; 
    dispatch_release(queue); 
    NSString* key = (NSString*)kCVPixelBufferPixelFormatTypeKey; 
    NSNumber* value = [NSNumber 
numberWithUnsignedInt:kCVPixelFormatType_32BGRA]; 
    NSDictionary* videoSettings = [NSDictionary 
dictionaryWithObject:value forKey:key]; 
    [captureOutput setVideoSettings:videoSettings]; 
    self.captureSession = [[AVCaptureSession alloc] init]; 
    [self.captureSession addInput:captureInput]; 
    [self.captureSession addOutput:captureOutput]; 
    [self.captureSession startRunning]; 
    self.customLayer = [CALayer layer]; 
    self.customLayer.frame = self.view.bounds; 
    self.customLayer.transform = CATransform3DRotate( 
CATransform3DIdentity, M_PI/2.0f, 0, 0, 1); 
    self.customLayer.contentsGravity = kCAGravityResizeAspectFill; 
    [self.view.layer addSublayer:self.customLayer]; 
    self.imageView = [[UIImageView alloc] init]; 
    self.imageView.frame = CGRectMake(0, 0, 100, 100); 
     [self.view addSubview:self.imageView]; 
    self.prevLayer = [AVCaptureVideoPreviewLayer 
layerWithSession: self.captureSession]; 
    self.prevLayer.frame = CGRectMake(100, 0, 100, 100); 
    self.prevLayer.videoGravity = AVLayerVideoGravityResizeAspectFill; 
    [self.view.layer addSublayer: self.prevLayer]; 
} 

#pragma mark - 
#pragma mark AVCaptureSession delegate 
- (void)captureOutput:(AVCaptureOutput *)captureOutput 
didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer 
       fromConnection:(AVCaptureConnection *)connection 
{ 

    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; 

    CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer); 
    CVPixelBufferLockBaseAddress(imageBuffer,0); 
    uint8_t *baseAddress = (uint8_t *)CVPixelBufferGetBaseAddress(imageBuffer); 
    size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer); 
    size_t width = CVPixelBufferGetWidth(imageBuffer); 
    size_t height = CVPixelBufferGetHeight(imageBuffer); 

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); 
    CGContextRef newContext = CGBitmapContextCreate(baseAddress, 
width, height, 8, bytesPerRow, colorSpace, 
kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst); 
    CGImageRef newImage = CGBitmapContextCreateImage(newContext); 

    CGContextRelease(newContext); 
    CGColorSpaceRelease(colorSpace); 

    [self.customLayer performSelectorOnMainThread:@selector(setContents:) 
withObject: (id) newImage waitUntilDone:YES]; 

    UIImage *image= [UIImage imageWithCGImage:newImage scale:1.0 
orientation:UIImageOrientationRight]; 

    CGImageRelease(newImage); 

    [self.imageView performSelectorOnMainThread:@selector(setImage:) 
withObject:image waitUntilDone:YES]; 

    CVPixelBufferUnlockBaseAddress(imageBuffer,0); 

    [pool drain]; 
} 

#pragma mark - 
#pragma mark Memory management 

- (void)viewDidUnload { 
    self.imageView = nil; 
    self.customLayer = nil; 
    self.prevLayer = nil; 
} 

- (void)dealloc { 
    [self.captureSession release]; 
    [super dealloc]; 
}