Question

我尝试编写ios相机，并且我采用了部分代码from apple：

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

     < Add your code here that uses the image >

}

我需要在程序的任何地方调用此函数。但是要求它创建一个(CMSampleBufferRef)的对象类型。怎么做？

我试着写一些像：

buf1 = [[CMSampleBufferRef alloc]init]

但这是错误的方式。

Answer 1

这是我目前用于在swift3中模拟CMSampleBuffer单元测试的片段：

fileprivate func getCMSampleBuffer() -> CMSampleBuffer {
    var pixelBuffer : CVPixelBuffer? = nil
    CVPixelBufferCreate(kCFAllocatorDefault, 100, 100, kCVPixelFormatType_32BGRA, nil, &pixelBuffer)

    var info = CMSampleTimingInfo()
    info.presentationTimeStamp = kCMTimeZero
    info.duration = kCMTimeInvalid
    info.decodeTimeStamp = kCMTimeInvalid


    var formatDesc: CMFormatDescription? = nil
    CMVideoFormatDescriptionCreateForImageBuffer(kCFAllocatorDefault, pixelBuffer!, &formatDesc)

    var sampleBuffer: CMSampleBuffer? = nil

    CMSampleBufferCreateReadyWithImageBuffer(kCFAllocatorDefault,
                                             pixelBuffer!,
                                             formatDesc!,
                                             &info,
                                             &sampleBuffer);

    return sampleBuffer!
}

Answer 2

@Rotem Tamir 答案的 Swift 5 版本

fileprivate func getCMSampleBuffer() -> CMSampleBuffer {
    var pixelBuffer: CVPixelBuffer?
    CVPixelBufferCreate(kCFAllocatorDefault, 100, 100, kCVPixelFormatType_32BGRA, nil, &pixelBuffer)

    var info = CMSampleTimingInfo()
    info.presentationTimeStamp = CMTime.zero
    info.duration = CMTime.invalid
    info.decodeTimeStamp = CMTime.invalid

    var formatDesc: CMFormatDescription?
    CMVideoFormatDescriptionCreateForImageBuffer(allocator: kCFAllocatorDefault,
                                                 imageBuffer: pixelBuffer!,
                                                 formatDescriptionOut: &formatDesc)

    var sampleBuffer: CMSampleBuffer?

    CMSampleBufferCreateReadyWithImageBuffer(allocator: kCFAllocatorDefault,
                                             imageBuffer: pixelBuffer!,
                                             formatDescription: formatDesc!,
                                             sampleTiming: &info,
                                             sampleBufferOut: &sampleBuffer)

    return sampleBuffer!
}

如何创建Sample Buffer（CMSampleBufferRef）的实例？

2 个答案: