Question

let duration = CMSampleBufferGetDuration(self)
let timeStamp = CMSampleBufferGetPresentationTimeStamp(self)
let decodeTimeStamp = CMSampleBufferGetDecodeTimeStamp(self)
let sampleTime = CMSampleTimingInfo(duration: duration, presentationTimeStamp: timeStamp, decodeTimeStamp: decodeTimeStamp)

let videoInfo: CMVideoFormatDescriptionRef?
CMVideoFormatDescriptionCreateForImageBuffer(kCFAllocatorDefault, pixelBuffer!, &videoInfo)

var oBuf: CMSampleBufferRef?
CMSampleBufferCreateForImageBuffer(kCFAllocatorDefault, pixelBuffer!, true, nil, nil, videoInfo!, sampleTime, &oBuf)

self是CMSampleBufferRef的一个实例。

最后一行抛出构建错误：Cannot convert value of type 'CMSampleTimingInfo' to expected argument type 'UnsafePointer<CMSampleTimingInfo>'

Answer 1

是的，您正在传递CMSampleTimingInfo并且该函数需要UnsafePointer<CMSampleTimingInfo>。我没有尝试过，但其他SO答案（like this）似乎暗示了以下内容：

withUnsafePointer(&sampleTime) {
    (unsafeSampleTime: UnsafePointer<CMSampleTimingInfo>) -> Void in
    CMSampleBufferCreateForImageBuffer(kCFAllocatorDefault, pixelBuffer!, true, nil, nil, videoInfo!, unsafeSampleTime, &oBuf)
}

如果你通过函数的签名来解决sampleTime的问题，看起来你会遇到与oBuf相同的问题。在这种情况下，您需要withUnsafeMutablePointer。

Answer 2

这是另一种方法..将var用于sampleTime

let duration = CMSampleBufferGetDuration(self)
let timeStamp = CMSampleBufferGetPresentationTimeStamp(self)
let decodeTimeStamp = CMSampleBufferGetDecodeTimeStamp(self)
var sampleTime = CMSampleTimingInfo(duration: duration, presentationTimeStamp: timeStamp, decodeTimeStamp: decodeTimeStamp)

var videoInfo: CMVideoFormatDescriptionRef? = nil
CMVideoFormatDescriptionCreateForImageBuffer(kCFAllocatorDefault, pixelBuffer!, &videoInfo)

var oBuf: CMSampleBufferRef?
CMSampleBufferCreateForImageBuffer(kCFAllocatorDefault, pixelBuffer!, true, nil, nil, videoInfo!, &sampleTime, &oBuf)

我接受这个作为答案，因为语法比withUnsafePointer()方法更清晰。但如果您愿意使用它，withUnsafePointer也会起作用。

无法将“CMSampleTimingInfo”类型的值转换为预期的参数类型“UnsafePointer <cmsampletiminginfo>”

2 个答案: