IOS4直接获取摄像头数据

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

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#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]; }   @end

原文来自：http://www.benjaminloulier.com/articles/ios4-and-direct-access-to-the-camera