IOS4直接获取摄像头数据(收藏)

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];
}

@end