initWithCVPixelBuffer失败,因为CVPixelBufferRef不是非IOSurface支持的

Question

我收到YUV帧(kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange),当从CVPixelBufferRef创建CIImage时,我得到:

initWithCVPixelBuffer失败,因为CVPixelBufferRef不是非IOSurface支持的.

CVPixelBufferRef pixelBuffer;

size_t planeWidth[] = { width, width / 2 };
size_t planeHeight[] = { height, height / 2};
size_t planeBytesPerRow[] = { width, width / 2 };

CVReturn ret = CVPixelBufferCreateWithBytes(
kCFAllocatorDefault, width, height, kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange,
data, bytesPerRow, 0, 0, 0, &pixelBuffer
);

if (ret != kCVReturnSuccess)
{
    NSLog(@"FAILED");

    CVPixelBufferRelease(pixelBuffer);

    return;
}

CVPixelBufferLockBaseAddress(pixelBuffer, 0);

// fails
CIImage * image = [[CIImage alloc] initWithCVPixelBuffer:pixelBuffer];

CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);

CVPixelBufferRelease(pixelBuffer);

[image release];

Answer 1

我假设问题是:"为什么我会收到这个错误？"

要使CVPixelBuffer支持IOSurface,您需要在创建CVPixelBuffer时设置它们的属性.现在,您将传递"0"作为CVPixelBufferCreateWithBytes中的倒数第二个参数.

在CVPixelBufferCreate中传递带有kCVPixelBufferIOSurfacePropertiesKey键的字典和值为空字典的值(使用默认IOSurface选项,其他未记录)(因为您不能将kCVPixelBufferIOSurfacePropertiesKey与CVPixelBufferCreateWithBytes一起使用),将正确的字节复制到创建的CVPixelBuffer(不要忘记字节对齐).这就是你如何使它成为IOSurface支持的.

虽然我不确定它是否会因像素格式而删除所有错误.我的理解是GPU必须能够以像素格式保存纹理才能用作IOSurfaces,尽管我不是100%肯定.

注意:在此SO答案中可以找到kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange的正确复制像素字节.