ios4下不使用私有API，轻松打开摄像头，获取摄像流
第一步：初始化AVCaptureSession，添加输入，输出源

#import <AVFoundation/AVFoundation.h>// Create and configure a capture session and start it running- (void)setupCaptureSession {    NSError *error = nil;    // Create the session    AVCaptureSession *session = [[AVCaptureSession alloc] init];    // Configure the session to produce lower resolution video frames, if your     // processing algorithm can cope. We'll specify medium quality for the    // chosen device.    session.sessionPreset = AVCaptureSessionPresetMedium;    // Find a suitable AVCaptureDevice    AVCaptureDevice *device = [AVCaptureDevice                             defaultDeviceWithMediaType:AVMediaTypeVideo];    // Create a device input with the device and add it to the session.    AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device                                                                     error:&error];    if (!input) {        // Handling the error appropriately.    }    [session addInput:input];    // Create a VideoDataOutput and add it to the session    AVCaptureVideoDataOutput *output = [[[AVCaptureVideoDataOutput alloc] init] autorelease];    [session addOutput:output];    // Configure your output.    dispatch_queue_t queue = dispatch_queue_create("myQueue", NULL);    [output setSampleBufferDelegate:self queue:queue];    dispatch_release(queue);    // Specify the pixel format    output.videoSettings =                 [NSDictionary dictionaryWithObject:                    [NSNumber numberWithInt:kCVPixelFormatType_32BGRA]                     forKey:(id)kCVPixelBufferPixelFormatTypeKey];    // If you wish to cap the frame rate to a known value, such as 15 fps, set     // minFrameDuration.    output.minFrameDuration = CMTimeMake(1, 15);    // Start the session running to start the flow of data    [session startRunning];    // Assign session to an ivar.    [self setSession:session];}

第二步：实现AVCaptureVideoDataOutputSampleBufferDelegate协议方法

// Delegate routine that is called when a sample buffer was written- (void)captureOutput:(AVCaptureOutput *)captureOutput          didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer          fromConnection:(AVCaptureConnection *)connection{     // Create a UIImage from the sample buffer data    UIImage *image = [self imageFromSampleBuffer:sampleBuffer];     < Add your code here that uses the image >}// Create a UIImage from sample buffer data- (UIImage *) imageFromSampleBuffer:(CMSampleBufferRef) sampleBuffer {    CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);    // Lock the base address of the pixel buffer    CVPixelBufferLockBaseAddress(imageBuffer,0);    // Get the number of bytes per row for the pixel buffer    size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer);     // Get the pixel buffer width and height    size_t width = CVPixelBufferGetWidth(imageBuffer);     size_t height = CVPixelBufferGetHeight(imageBuffer);     // Create a device-dependent RGB color space    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();     if (!colorSpace)     {        NSLog(@"CGColorSpaceCreateDeviceRGB failure");        return nil;    }    // Get the base address of the pixel buffer    void *baseAddress = CVPixelBufferGetBaseAddress(imageBuffer);    // Get the data size for contiguous planes of the pixel buffer.    size_t bufferSize = CVPixelBufferGetDataSize(imageBuffer);     // Create a Quartz direct-access data provider that uses data we supply    CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, baseAddress, bufferSize,                                                             NULL);    // Create a bitmap image from data supplied by our data provider    CGImageRef cgImage =         CGImageCreate(width,                        height,                        8,                        32,                        bytesPerRow,                        colorSpace,                        kCGImageAlphaNoneSkipFirst | kCGBitmapByteOrder32Little,                        provider,                        NULL,                        true,                        kCGRenderingIntentDefault);    CGDataProviderRelease(provider);    CGColorSpaceRelease(colorSpace);    // Create and return an image object representing the specified Quartz image    UIImage *image = [UIImage imageWithCGImage:cgImage];    CGImageRelease(cgImage);    CVPixelBufferUnlockBaseAddress(imageBuffer, 0);    return image;}

好了，现在就可以自由的显示和分析获取的UIImage了，再也不用使用私有API了 1 楼 handy.wang 2010-08-12 Hi dude. Can you share with me how to catch the stream from camera with private API in iOS3. THX. 2 楼 lanter206 2011-01-13 朋友，你的这段代码和官网上的AVCaptureSession类的介绍中是一样的，但是我在调试的时候没有通过，你有调试过吗？手上项目涉及到这方面 3 楼 cwh643 2011-02-15 lanter206 写道朋友，你的这段代码和官网上的AVCaptureSession类的介绍中是一样的，但是我在调试的时候没有通过，你有调试过吗？手上项目涉及到这方面
我这里试了没有问题的，可以使用的