相关疑难解决方法(0)

我在我的iPhone应用程序中使用CGBitmapContextCreateImage时遇到问题.

我正在使用AV Foundation Framework使用此方法抓取相机帧:

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection {
    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);
    CVPixelBufferUnlockBaseAddress(imageBuffer,0);
    CGContextRelease(newContext);
    CGColorSpaceRelease(colorSpace);

    UIImage *image= [UIImage imageWithCGImage:newImage scale:1.0 orientation:UIImageOrientationRight];
    self.imageView.image = image;

    CGImageRelease(newImage);

} 

但是,我在调试控制台中看到一个错误:

<Error>: CGDataProviderCreateWithCopyOfData: vm_copy failed: status 2.

有没有人见过这个？通过注释掉我的问题,我将问题排成一行:

CGImageRef newImage = CGBitmapContextCreateImage(newContext);

但我不知道如何摆脱它.从功能上讲,它很棒.很明显,CGImage正在创建,但我需要知道是什么导致错误,所以它不会影响其他部分. …

我有一个应用程序捕获kCVPixelFormatType_420YpCbCr8BiPlanarFullRange格式的实时视频来处理Y通道.根据Apple的文档:

kCVPixelFormatType_420YpCbCr8BiPlanarFullRange双平面分量Y'CbCr 8位4:2:0,全范围(亮度= [0,255]色度= [1,255]).baseAddr指向big-endian CVPlanarPixelBufferInfo_YCbCrBiPlanar结构.

我想在UIViewController中展示一些这些帧,是否有任何API可以转换为kCVPixelFormatType_32BGRA格式？您能给出一些提示来调整Apple提供的这种方法吗？

// 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, 0);

    // Get the number of bytes per row for the pixel buffer
    void *baseAddress = CVPixelBufferGetBaseAddress(imageBuffer);

    // Get the number of bytes per row for the pixel buffer
    size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer); …

我正在尝试将 YUV 图像转换为 CIIMage 并最终转换为 UIImage。我在这些方面相当新手，并试图找出一种简单的方法来做到这一点。据我所知，从 iOS6 YUV 可以直接用于创建 CIImage 但当我试图创建它时，CIImage 只持有一个 nil 值。我的代码是这样的->

NSLog(@"Started DrawVideoFrame\n");

CVPixelBufferRef pixelBuffer = NULL;

CVReturn ret = CVPixelBufferCreateWithBytes(
                                            kCFAllocatorDefault, iWidth, iHeight, kCVPixelFormatType_420YpCbCr8BiPlanarFullRange,
                                            lpData, bytesPerRow, 0, 0, 0, &pixelBuffer
                                            );

if(ret != kCVReturnSuccess)
{
    NSLog(@"CVPixelBufferRelease Failed");
    CVPixelBufferRelease(pixelBuffer);
}

NSDictionary *opt =  @{ (id)kCVPixelBufferPixelFormatTypeKey :
                      @(kCVPixelFormatType_420YpCbCr8BiPlanarFullRange) };

CIImage *cimage = [CIImage imageWithCVPixelBuffer:pixelBuffer options:opt];
NSLog(@"CURRENT CIImage -> %p\n", cimage);

UIImage *image = [UIImage imageWithCIImage:cimage scale:1.0 orientation:UIImageOrientationUp];
NSLog(@"CURRENT UIImage -> %p\n", image);

这里 lpData 是 YUV 数据，它是一个无符号字符数组。

这看起来也很有趣： …