iPhone摄像头设备获取(分离简化版）

目的：打开、关闭前置摄像头，绘制图像，并获取摄像头的二进制数据。
需要的库
AVFoundation.framework 、CoreVideo.framework 、CoreMedia.framework 、QuartzCore.framework
该摄像头捕抓必须编译真机的版本，模拟器下编译不了。
函数说明

- ( void )createControl
{
// UI界面控件的创建
}

- (AVCaptureDevice *)getFrontCamera;
获取前置摄像头设备
- (void)startVideoCapture;
打开摄像头并开始捕捉图像
其中代码：
AVCaptureVideoPreviewLayer* previewLayer = [AVCaptureVideoPreviewLayer layerWithSession:  self -> avCaptureSession ];
previewLayer. frame  =  localView . bounds ;
previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
[self->localView.layer addSublayer: previewLayer];  
为把图片画到UIView里面

- ( void )stopVideoCapture:( id )arg；

关闭摄像头，停止捕抓图像
其中代码：

for ( UIView * view in self -> localView . subviews ) {
[ view removeFromSuperview ];
}


为移除摄像头图像的View
详情见代码，代码拷过去可以直接使用      Over!!!!


代码：
头文件：

//
//  AVCallController.h
//  Pxlinstall
//
//  Created by Lin Charlie C. on 11-3-24.
//  Copyright 2011  xxxx. All rights reserved.
//


#import  <UIKit/UIKit.h>
#import  <AVFoundation/AVFoundation.h>




@interface  AVCallController : UIViewController <AVCaptureVideoDataOutputSampleBufferDelegate>
{
//UI
UILabel * labelState ;
UIButton * btnStartVideo ;
UIView * localView ;

AVCaptureSession*  avCaptureSession ;
AVCaptureDevice * avCaptureDevice ;
BOOL firstFrame ;  // 是否为第一帧
int producerFps ;


}
@property  ( nonatomic ,  retain ) AVCaptureSession *avCaptureSession;
@property  ( nonatomic ,  retain ) UILabel *labelState;


- ( void )createControl;
- (AVCaptureDevice *)getFrontCamera;
- ( void )startVideoCapture;
- ( void )stopVideoCapture:( id )arg;
@end
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
实现文件：
     //
//  AVCallController.m
//  Pxlinstall
//
//  Created by Lin Charlie C. on 11-3-24.
//  Copyright 2011  高鸿移通. All rights reserved.
//


#import  "AVCallController.h"




@implementation  AVCallController


@synthesize  avCaptureSession;
@synthesize  labelState;


// The designated initializer.  Override if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad.
/*
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization.
    }
    return self;
}
*/
-( id )init
{
if ( self = [ super init ])
{
firstFrame =  YES ;
producerFps =  50 ;
}
return self ;
}


// Implement loadView to create a view hierarchy programmatically, without using a nib.
- ( void )loadView {
[ super loadView ];
[ self createControl ];
}




/*
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
    [super viewDidLoad];
}
*/


/*
// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    // Return YES for supported orientations.
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
*/


- ( void )didReceiveMemoryWarning {
// Releases the view if it doesn't have a superview.
[ super didReceiveMemoryWarning ];

// Release any cached data, images, etc. that aren't in use.
}


- ( void )viewDidUnload {
[ super viewDidUnload ];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}




- ( void )dealloc {
    [ super   dealloc ];
}


#pragma mark -
#pragma mark createControl
- ( void )createControl
{
//UI展示
self . view . backgroundColor = [ UIColor grayColor ];
labelState = [[ UILabel alloc ]  initWithFrame : CGRectMake ( 10 ,  20 ,  220 ,  30 )];
labelState . backgroundColor = [ UIColor clearColor ];
[ self . view addSubview : labelState ];
[ labelState release ];

btnStartVideo = [[ UIButton alloc ]  initWithFrame : CGRectMake ( 20 ,  350 ,  80 ,  50 )];
[ btnStartVideo setTitle : @"Star" forState : UIControlStateNormal ];


[ btnStartVideo setBackgroundImage :[ UIImage imageNamed : @"Images/button.png" ]  forState : UIControlStateNormal ];
[ btnStartVideo addTarget : self action : @selector ( startVideoCapture )  forControlEvents : UIControlEventTouchUpInside ];
[ self . view addSubview : btnStartVideo ];
[ btnStartVideo release ];

UIButton * stop = [[ UIButton alloc ]  initWithFrame : CGRectMake ( 120 ,  350 ,  80 ,  50 )];
[stop  setTitle : @"Stop" forState : UIControlStateNormal ];

[stop  setBackgroundImage :[ UIImage imageNamed : @"Images/button.png" ]  forState : UIControlStateNormal ];
[stop  addTarget : self action : @selector ( stopVideoCapture :)  forControlEvents : UIControlEventTouchUpInside ];
[ self . view   addSubview :stop];
[stop  release ];

localView = [[ UIView alloc ]  initWithFrame : CGRectMake ( 40 ,  50 ,  200 ,  300 )];
[ self . view addSubview : localView ];
[ localView release ];


}
#pragma mark -
#pragma mark VideoCapture
- (AVCaptureDevice *)getFrontCamera
{
//获取前置摄像头设备
NSArray  *cameras = [AVCaptureDevice devicesWithMediaType: AVMediaTypeVideo ];
     for  (AVCaptureDevice *device  in  cameras)
{
         if  (device. position  == AVCaptureDevicePositionFront)
             return  device;
    }
     return  [AVCaptureDevice defaultDeviceWithMediaType: AVMediaTypeVideo ];

}
- ( void )startVideoCapture
{
//打开摄像设备，并开始捕抓图像
[ labelState setText : @"Starting Video stream" ];
if ( self -> avCaptureDevice ||  self -> avCaptureSession )
{
[ labelState setText : @"Already capturing" ];
return ;
}

if (( self -> avCaptureDevice  = [ self   getFrontCamera ]) ==  nil )
{
[ labelState setText : @"Failed to get valide capture device" ];
return ;
}

NSError  *error =  nil ;
    AVCaptureDeviceInput *videoInput = [AVCaptureDeviceInput deviceInputWithDevice: self -> avCaptureDevice  error:&error];
     if  (!videoInput)
{
[ labelState setText : @"Failed to get video input" ];
self -> avCaptureDevice =  nil ;
         return ;
    }

     self -> avCaptureSession  = [[AVCaptureSession  alloc ]  init ];
     self -> avCaptureSession .sessionPreset = AVCaptureSessionPresetLow;
    [ self -> avCaptureSession  addInput:videoInput];

// Currently, the only supported key is kCVPixelBufferPixelFormatTypeKey. Recommended pixel format choices are 
// kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange or kCVPixelFormatType_32BGRA. 
// On iPhone 3G, the recommended pixel format choices are kCVPixelFormatType_422YpCbCr8 or kCVPixelFormatType_32BGRA.
//
    AVCaptureVideoDataOutput *avCaptureVideoDataOutput = [[AVCaptureVideoDataOutput  alloc ]  init ];
NSDictionary *settings = [[ NSDictionary alloc ]  initWithObjectsAndKeys :
//[NSNumber numberWithUnsignedInt:kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange], kCVPixelBufferPixelFormatTypeKey,
[ NSNumber numberWithInt : 240 ], ( id ) kCVPixelBufferWidthKey ,
                              [ NSNumber   numberWithInt : 320 ], ( id ) kCVPixelBufferHeightKey ,
   nil ];
    avCaptureVideoDataOutput.videoSettings = settings;
    [settings  release ];
    avCaptureVideoDataOutput.minFrameDuration =  CMTimeMake ( 1 ,  self -> producerFps );
/*We create a serial queue to handle the processing of our frames*/
dispatch_queue_t queue =  dispatch_queue_create ( "org.doubango.idoubs" ,  NULL );
    [avCaptureVideoDataOutput setSampleBufferDelegate: self  queue:queue];
    [ self -> avCaptureSession  addOutput:avCaptureVideoDataOutput];
    [avCaptureVideoDataOutput  release ];
dispatch_release (queue);

AVCaptureVideoPreviewLayer* previewLayer = [AVCaptureVideoPreviewLayer layerWithSession:  self -> avCaptureSession ];
previewLayer. frame  =  localView . bounds ;
previewLayer. videoGravity =  AVLayerVideoGravityResizeAspectFill ;

[ self -> localView . layer   addSublayer : previewLayer];

self -> firstFrame =  YES ;
    [ self -> avCaptureSession  startRunning];

[ labelState setText : @"Video capture started" ];

}
- ( void )stopVideoCapture:( id )arg
{
//停止摄像头捕抓
if ( self -> avCaptureSession ){
[ self -> avCaptureSession  stopRunning];
self -> avCaptureSession =  nil ;
[ labelState setText : @"Video capture stopped" ];
}
self -> avCaptureDevice =  nil ;
//移除localView里面的内容
for ( UIView * view in self -> localView . subviews ) {
[ view removeFromSuperview ];
}
}
#pragma mark -
#pragma mark AVCaptureVideoDataOutputSampleBufferDelegate
- ( void )captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection 
{
//捕捉数据输出 要怎么处理虽你便
CVPixelBufferRef  pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
/*Lock the buffer*/
if ( CVPixelBufferLockBaseAddress (pixelBuffer,  0 ) ==  kCVReturnSuccess )
{
         UInt8  *bufferPtr = ( UInt8  *) CVPixelBufferGetBaseAddress (pixelBuffer);
         size_t  buffeSize =  CVPixelBufferGetDataSize (pixelBuffer);

if ( self -> firstFrame )
{ 
if ( 1 )
{
//第一次数据要求：宽高，类型
int  width =  CVPixelBufferGetWidth (pixelBuffer);
int  height =  CVPixelBufferGetHeight (pixelBuffer);

int  pixelFormat =  CVPixelBufferGetPixelFormatType (pixelBuffer);
switch  (pixelFormat) {
case kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange :
//TMEDIA_PRODUCER(producer)->video.chroma = tmedia_nv12; // iPhone 3GS or 4
NSLog ( @"Capture pixel format=NV12" );
break ;
case kCVPixelFormatType_422YpCbCr8 :
//TMEDIA_PRODUCER(producer)->video.chroma = tmedia_uyvy422; // iPhone 3
NSLog ( @"Capture pixel format=UYUY422" );
break ;
default :
//TMEDIA_PRODUCER(producer)->video.chroma = tmedia_rgb32;
NSLog ( @"Capture pixel format=RGB32" );
break ;
}

self -> firstFrame  =  NO ;
}
}
/*We unlock the buffer*/
CVPixelBufferUnlockBaseAddress (pixelBuffer,  0 ); 
    }
/*We create an autorelease pool because as we are not in the main_queue our code is
 not executed in the main thread. So we have to create an autorelease pool for the thread we are in*/
// NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
// 
//    CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer); 
//    /*Lock the image buffer*/
//    CVPixelBufferLockBaseAddress(imageBuffer,0); 
//    /*Get information about the image*/
//    uint8_t *baseAddress = (uint8_t *)CVPixelBufferGetBaseAddress(imageBuffer); 
//    size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer); 
//    size_t width = CVPixelBufferGetWidth(imageBuffer); 
//    size_t height = CVPixelBufferGetHeight(imageBuffer);  
//    
//    /*Create a CGImageRef from the CVImageBufferRef*/
//    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); 
//    CGContextRef newContext = CGBitmapContextCreate(baseAddress, width, height, 8, bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst);
//    CGImageRef newImage = CGBitmapContextCreateImage(newContext); 
// 
//    /*We release some components*/
//    CGContextRelease(newContext); 
//    CGColorSpaceRelease(colorSpace);
//    
//    /*We display the result on the custom layer. All the display stuff must be done in the main thread because
//  UIKit is no thread safe, and as we are not in the main thread (remember we didn't use the main_queue)
//  we use performSelectorOnMainThread to call our CALayer and tell it to display the CGImage.*/
// [self.customLayer performSelectorOnMainThread:@selector(setContents:) withObject: (id) newImage waitUntilDone:YES];
// 
// /*We display the result on the image view (We need to change the orientation of the image so that the video is displayed correctly).
//  Same thing as for the CALayer we are not in the main thread so ...*/
// UIImage *image= [UIImage imageWithCGImage:newImage scale:1.0 orientation:UIImageOrientationRight];
// 
// /*We relase the CGImageRef*/
// CGImageRelease(newImage);
// 
// [self.imageView performSelectorOnMainThread:@selector(setImage:) withObject:image waitUntilDone:YES];
// 
// /*We unlock the  image buffer*/
// CVPixelBufferUnlockBaseAddress(imageBuffer,0);
// 
// [pool drain];
}

@end

原文链接：http://www.cocoachina.com/bbs/read.php?tid=51754&page=1

http://www.cocoachina.com/bbs/read.php?tid=66400