如何在swift中将CMSampleBuffer转换为CMAttachmentBearer

Question

我是swift的新手，我想在(void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection委托中调用函数CMCopyDictionaryOfAttachments

我的代码：

// MARK: Delegates

func captureOutput(captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, fromConnection connection: AVCaptureConnection!) {
    // got an image
    let pixelBuffer : CVPixelBufferRef = CMSampleBufferGetImageBuffer(sampleBuffer)
    let attachments : CFDictionaryRef = CMCopyDictionaryOfAttachments(kCFAllocatorDefault, sampleBuffer, CMAttachmentMode( kCMAttachmentMode_ShouldPropagate)) as CFDictionaryRef!

}

这通过xcode :'CMSampleBuffer' is not identical to 'CMAttachmentBearer'得到了一个错误，那么我如何使用sampleBuffer作为目标，这段代码如果用objective-c编写就能正常工作

Answer 1

我猜您代码中的主要问题是您传递的是CMSampleBuffer而不是CVPixelBufferRef。

下一个问题是CMCopyDictionaryOfAttachments返回一个需要使用takeRetainedValue()进行转换的非托管实例。

func captureOutput(captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, fromConnection connection: AVCaptureConnection!) {
    // got an image
    let pixelBuffer : CVPixelBufferRef = CMSampleBufferGetImageBuffer(sampleBuffer)
    let attachments : [NSObject : AnyObject] = CMCopyDictionaryOfAttachments(kCFAllocatorDefault, pixelBuffer, CMAttachmentMode( kCMAttachmentMode_ShouldPropagate)).takeRetainedValue()

}