0

这是我的代码

- (void)captureOutput:(AVCaptureOutput *)captureOutput 
didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer 
   fromConnection:(AVCaptureConnection *)connection
{ 
    // Create a UIImage from the sample buffer data
    UIImage *image = [self imageFromSampleBuffer:sampleBuffer];
    dispatch_async(dispatch_get_main_queue(), ^{
      [[self imgView] setImage:image];
    });
}

从样本缓冲区数据创建 UIImage

- (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.
    static CGColorSpaceRef colorSpace = NULL;
    if (colorSpace == NULL) {
        colorSpace = CGColorSpaceCreateDeviceRGB();
    if (colorSpace == NULL) {
           // Handle the error appropriately.
           return nil;
        }
    }

    // Get the base address of the pixel buffer.
    uint8_t *baseAddress = malloc( bytesPerRow * height );    
    memcpy( baseAddress, CVPixelBufferGetBaseAddress(imageBuffer), bytesPerRow * height );

    // 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 dataProvider = CGDataProviderCreateWithData(NULL, baseAddress, bufferSize, NULL);
    // Create a bitmap image from data supplied by the data provider.
    CGImageRef cgImage = CGImageCreate(width, height, 8, 32, bytesPerRow,
              colorSpace, kCGImageAlphaNoneSkipFirst | kCGBitmapByteOrder32Little, dataProvider, NULL, true, kCGRenderingIntentDefault);

    CGDataProviderRelease(dataProvider);

    // Create and return an image object to represent the Quartz image.
    UIImage *image = [UIImage imageWithCGImage:cgImage];
    CGImageRelease(cgImage);
    free(baseAddress);
    CVPixelBufferUnlockBaseAddress(imageBuffer, 0);

    return image;
}

我的图像视图中仍然没有图像，任何人都可以帮我找出错误。

提前致谢。

4

4 回答 4

3

这是使我工作的代码：

- (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.imgView.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, 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); 


// 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, 8, 
                                             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,0);


// 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);
}
于 2012-07-17T04:52:26.790 回答
0

试试这个：

- (UIImage *) imageFromSampleBuffer:(CMSampleBufferRef) sampleBuffer 
{
    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);

    CGContextRelease(newContext);
    CGColorSpaceRelease(colorSpace);

    return [UIImage imageWithCGImage:newImage];

    CGImageRelease(newImage);
    CVPixelBufferUnlockBaseAddress(imageBuffer, 0);
}
于 2012-06-27T22:32:58.703 回答
0

使用 GLKView 加速渲染；然后，将此代码插入您的委托方法中：

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
{
    CMFormatDescriptionRef formatDesc = CMSampleBufferGetFormatDescription(sampleBuffer);

    // update the video dimensions information
    _currentVideoDimensions = CMVideoFormatDescriptionGetDimensions(formatDesc);

    CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);

// If you want to apply filters to your UIImage before you display it...

    CIImage *tempImage = [CIImage imageWithCVPixelBuffer:(CVPixelBufferRef)imageBuffer options:nil];
    CIFilter *filter = [CIFilter filterWithName: @"CIExposureAdjust" keysAndValues:@"inputImage", tempImage, nil];
    [filter setValue:@(self.tag) forKey:@"inputEV"];
    CIFilter *filter2 = [CIFilter filterWithName: @"CILinearToSRGBToneCurve" keysAndValues:@"inputImage", [filter valueForKey: @"outputImage"], nil];
    CIFilter *filter3 = [CIFilter filterWithName: @"CIGammaAdjust" keysAndValues:@"inputImage", [filter2 valueForKey: @"outputImage"], nil];
    [filter3 setValue:@(self.tag) forKey:@"inputPower"];
    CIImage *sourceImage = [filter3 valueForKey: @"outputImage"];

    CGRect sourceExtent = sourceImage.extent;

    CGFloat sourceAspect = sourceExtent.size.width / sourceExtent.size.height;
    CGFloat previewAspect = _videoPreviewViewBounds.size.width  / _videoPreviewViewBounds.size.height;

    // we want to maintain the aspect radio of the screen size, so we clip the video image
    CGRect drawRect = sourceExtent;
    if (sourceAspect > previewAspect)
    {
        // use full height of the video image, and center crop the width
        drawRect.origin.x += (drawRect.size.width - drawRect.size.height * previewAspect) / 2.0;
        drawRect.size.width = drawRect.size.height * previewAspect;
    }
    else
    {
        // use full width of the video image, and center crop the height
        drawRect.origin.y += (drawRect.size.height - drawRect.size.width / previewAspect) / 2.0;
        drawRect.size.height = drawRect.size.width / previewAspect;
    }

    [_videoPreviewView bindDrawable];

    if (_eaglContext != [EAGLContext currentContext])
        [EAGLContext setCurrentContext:_eaglContext];

    // clear eagl view to grey
    glClearColor(0.5, 0.5, 0.5, 1.0);
    glClear(GL_COLOR_BUFFER_BIT);

    // set the blend mode to "source over" so that CI will use that
    glEnable(GL_BLEND);
    glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);

    [_ciContext drawImage:sourceImage inRect:_videoPreviewViewBounds fromRect:drawRect];

    [_videoPreviewView display];
}

您始终可以轻松地将 CIImage 转换为 UIImage；但为什么？通过将图像渲染到 EAGLContext 中，您可以获得 GPU 加速的图像显示。我想不出你为什么需要 UIImage 除非这是你知道的唯一方法。

请注意，此代码可以减少到几行，但很少有人需要在使用示例缓冲区时正确定位和着色视频文件中的帧的方法。如果是这样的话，这涵盖了您需要的一切。（我认为你会发现很难让从样本缓冲区生成的 UIImage 正确定位自身......）

于 2017-05-13T15:43:02.713 回答
-2

尝试使用

UIImage *image = [[UIImage alloc] initWithCGImage:];

代替

UIImage *image = [UIImage imageWithCGImage:cgImage];
于 2012-06-26T06:19:14.180 回答