设置CMSampleBuffer示例附件(Swift)

Question

我正在尝试为CMSampleBuffer中的每个示例设置CMSampleBuffer。

到目前为止，我已经尝试获取字典(Dictionary<NSObject, AnyObject>、NSDictionary、CFDictionary)，并在CMSampleBuffer及其附件上调用CMSetAttachment。

为了检索附件，我使用CMSampleBufferGetSampleAttachmentsArray。

我该怎么用Swift来设置这些旗子呢？

Answer 1

以下是与Swift 4(应该适用于3)的解决方案(可能还远远不够完美)。

func setSampleBufferAttachments(_ sampleBuffer: CMSampleBuffer) {
    let attachments: CFArray! = CMSampleBufferGetSampleAttachmentsArray(sampleBuffer, true)
    let dictionary = unsafeBitCast(CFArrayGetValueAtIndex(attachments, 0),
        to: CFMutableDictionary.self)
    let key = Unmanaged.passUnretained(kCMSampleAttachmentKey_DisplayImmediately).toOpaque()
    let value = Unmanaged.passUnretained(kCFBooleanTrue).toOpaque()
    CFDictionarySetValue(dictionary, key, value)
}