调用视频流所使用框架：<Foundation/Foundation.h>
必须定义的参数：
1.AVCaptureDevice（捕获设备：前置、后置摄像头等）
2.AVCaptureInput（捕获输入：一般就是捕获设备的输入）
3.AVCaptureOutput（捕获输出：可输入为视频文件、图像文件等）
4.AVCaptureSession（调节多个输入输出）
关键代码：
- (void)setupCamera
{
NSError *error = nil; // Create the session
_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.
_input = [AVCaptureDeviceInput deviceInputWithDevice:device
error:&error];
if (!_input) {
// Handling the error appropriately.
}
[_session addInput:_input]; // Create a VideoDataOutput and add it to the session
_output = [[AVCaptureVideoDataOutput alloc] init];
[_session addOutput:_output]; // Configure your output.
dispatch_queue_t queue = dispatch_queue_create("myQueue", NULL);
[_output setSampleBufferDelegate:self queue: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(, ); // Start the session running to start the flow of data
[_session startRunning]; // Assign session to an ivar.
[self setSession:_session];
} // 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 *img = [self imageFromSampleBuffer:sampleBuffer]; /*
dispatch_async(dispatch_get_main_queue(), ^{
self.catchview.image=img;
});
*/ }
// Create a UIImage from sample buffer data
- (UIImage *) imageFromSampleBuffer:(CMSampleBufferRef) sampleBuffer
{ // Get a CMSampleBuffer's Core Video image buffer for the media data
CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
// Lock the base address of the pixel buffer
CVPixelBufferLockBaseAddress(imageBuffer, ); // 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); // Get the number of bytes per row for the pixel buffer
u_int8_t *baseAddress = (u_int8_t *)malloc(bytesPerRow*height);
memcpy( baseAddress, CVPixelBufferGetBaseAddress(imageBuffer), bytesPerRow * height ); // size_t bufferSize = CVPixelBufferGetDataSize(imageBuffer); // Create a device-dependent RGB color space
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); // Create a bitmap graphics context with the sample buffer data //The context draws into a bitmap which is `width'
// pixels wide and `height' pixels high. The number of components for each
// pixel is specified by `space'
CGContextRef context = CGBitmapContextCreate(baseAddress, width, height, ,
bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipFirst); // Create a Quartz image from the pixel data in the bitmap graphics context
CGImageRef quartzImage = CGBitmapContextCreateImage(context); // Unlock the pixel buffer
CVPixelBufferUnlockBaseAddress(imageBuffer,); // Free up the context and color space
CGContextRelease(context);
//CGColorSpaceRelease(colorSpace); // Create an image object from the Quartz image
UIImage *image = [UIImage imageWithCGImage:quartzImage scale:1.0 orientation:UIImageOrientationRight];
free(baseAddress);
// Release the Quartz image
CGImageRelease(quartzImage);
return (image);
}