如何将 YUV 转换为 iOS 的 CIImage

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 开始，YUV 可以直接用于创建 CIImage，但当我尝试创建它时，CIImage 仅保留一个 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);

这里的lpData是YUV数据，它是一个无符号字符数组。

这看起来也很有趣：vImageMatrix乘法，找不到任何这方面的例子。谁能帮我这个？

我也遇到过这个类似的问题。我试图将 YUV(NV12) 格式的数据显示到屏幕上。该解决方案正在我的项目中运行...

//YUV(NV12)-->CIImage--->UIImage Conversion
NSDictionary *pixelAttributes = @{kCVPixelBufferIOSurfacePropertiesKey : @{}};
CVPixelBufferRef pixelBuffer = NULL;

CVReturn result = CVPixelBufferCreate(kCFAllocatorDefault,
                                      640,
                                      480,
                                      kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange,
                                      (__bridge CFDictionaryRef)(pixelAttributes),
                                      &pixelBuffer);

CVPixelBufferLockBaseAddress(pixelBuffer,0);
unsigned char *yDestPlane = CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 0);

// Here y_ch0 is Y-Plane of YUV(NV12) data.
memcpy(yDestPlane, y_ch0, 640 * 480); 
unsigned char *uvDestPlane = CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 1);

// Here y_ch1 is UV-Plane of YUV(NV12) data. 
memcpy(uvDestPlane, y_ch1, 640*480/2);
CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);

if (result != kCVReturnSuccess) {
    NSLog(@"Unable to create cvpixelbuffer %d", result);
}

// CIImage Conversion    
CIImage *coreImage = [CIImage imageWithCVPixelBuffer:pixelBuffer];

CIContext *MytemporaryContext = [CIContext contextWithOptions:nil];
CGImageRef MyvideoImage = [MytemporaryContext createCGImage:coreImage
                                                    fromRect:CGRectMake(0, 0, 640, 480)];

// UIImage Conversion
UIImage *Mynnnimage = [[UIImage alloc] initWithCGImage:MyvideoImage 
                                                 scale:1.0 
                                           orientation:UIImageOrientationRight];

CVPixelBufferRelease(pixelBuffer);
CGImageRelease(MyvideoImage);

Here I am showing data structure of YUV(NV12) data and how we can get the Y-Plane(y_ch0) and UV-Plane(y_ch1) which is used to create CVPixelBufferRef. Let's look at the YUV(NV12) data structure.. If we look at the picture we can get following information about YUV(NV12),

• 总框架尺寸=宽度*高度*3/2，
• Y 平面尺寸 = 框架尺寸 * 2/3，
• UV 平面尺寸 = 框架尺寸 * 1/3，
• 数据存储在Y平面-->{Y1, Y2, Y3, Y4, Y5.....}。
• U 平面-->(U1, V1, U2, V2, U3, V3,......}。

希望对大家有所帮助。 :) 享受 IOS 开发的乐趣 :D