Question

我目前正试图弄清楚如何从网络摄像头改变帧以进行运动检测游戏。我是Objective-C的新手，我一直无法找到一种简单的方法来做到这一点。

我的问题是关于此方法的错误消息：

- (void)captureOutput:(QTCaptureOutput *)captureOutput 
  didOutputVideoFrame:(CVImageBufferRef)videoFrame
     withSampleBuffer:(QTSampleBuffer *)sampleBuffer 
       fromConnection:(QTCaptureConnection *)connection
{


    CIContext *myCIContext;
    const NSOpenGLPixelFormatAttribute attr[] = {
        NSOpenGLPFAAccelerated,
        NSOpenGLPFANoRecovery,
        NSOpenGLPFAColorSize, 32,
        0
    };
    NSOpenGLPixelFormat *pf = [[NSOpenGLPixelFormat alloc] initWithAttributes:(void *)&attr];
    myCIContext = [CIContext contextWithCGLContext: CGLGetCurrentContext()
                                       pixelFormat: [pf CGLPixelFormatObj]
                                           options: nil];
    CVImageBufferRef releasedImageBuffer;
    CVBufferRetain(videoFrame);

    CIImage *picture = [CIImage imageWithCVImageBuffer:releasedImageBuffer];
    NSRect frame = [self frame];
    CGRect imageRect;
    imageRect = [picture extent];

    [colorCorrectionFilter setValue:picture forKey:@"inputImage"];
    [effectFilter setValue:[colorCorrectionFilter valueForKey:@"outputImage"] forKey:@"inputImage"];

    // render our resulting image into our context
    [ciContext drawImage:[compositeFilter valueForKey:@"outputImage"] 
                 atPoint:CGPointMake((int)((frame.size.width - imageRect.size.width) * 0.5), (int)((frame.size.height - imageRect.size.height) * 0.5)) // use integer coordinates to avoid interpolation
                fromRect:imageRect];

    @synchronized(self)
    {
        //basically, have frame to be released refer to the current frame
        //then update the reference to the current frame with the next frame in the "video stream"
        releasedImageBuffer = mCurrentImageBuffer;
        mCurrentImageBuffer = videoFrame;
    }

    CVBufferRelease(releasedImageBuffer);

}

产生的错误消息显示：

warning: 'MyRecorderController' may not respond to '-frame'
error: invalid initializer

，突出显示的行是

NSRect frame = [self frame];

我的标题目前是这样的：

#import <QuickTime/ImageCompression.h>
#import <QuickTime/QuickTime.h>
#import <Cocoa/Cocoa.h>
#import <QTKit/QTKit.h>
#import <OpenGL/OpenGL.h>
#import <QuartzCore/QuartzCore.h>
#import <CoreVideo/CoreVideo.h>


@interface MyRecorderController : NSObject{ 
    IBOutlet QTCaptureView *mCaptureView;

    IBOutlet NSPopUpButton *videoDevicePopUp;
    NSMutableDictionary *namesToDevicesDictionary;
    NSString *defaultDeviceMenuTitle;

    CVImageBufferRef mCurrentImageBuffer;
    QTCaptureDecompressedVideoOutput *mCaptureDecompressedVideoOutput;

    // filters for CI rendering
    CIFilter            *colorCorrectionFilter; // hue saturation brightness control through one CI filter
    CIFilter            *effectFilter;          // zoom blur filter
    CIFilter            *compositeFilter;       // composites the timecode over the video
    CIContext           *ciContext;

    QTCaptureSession *mCaptureSession;
    QTCaptureMovieFileOutput *mCaptureMovieFileOutput;
    QTCaptureDeviceInput *mCaptureDeviceInput;

}

@end

我看过教程代码，但我不明白我做错了什么。据我所知（从各种示例代码判断）我不需要在此包含协议 - 这是其他网站建议的。我已经试过了，虽然它确实编译了但最终输出：

2011-01-18 10:19:11.511 MyRecorder[9972:c903] -[MyRecorderController frame]: unrecognized selector sent to instance 0x1001525f0
2011-01-18 10:19:11.512 MyRecorder[9972:c903] *** Ignoring exception: -[MyRecorderController frame]: unrecognized selector sent to instance 0x1001525f0

我做错了是什么导致了这个？如果没有，是否有更好的方法可以从网络摄像头操作帧（并将其输出到屏幕）？

谢谢堆！

Answer 1

您正在尝试在MyRecorderController上调用方法框架 - 它没有该方法。也许该类应该继承自UIView，或者您需要实现该方法。

问问自己你的意思是什么框架，并写出适当的方法。

NSRect框架无效的标识符= [自我框架]

1 个答案: