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