iOS CMSampleBuffer deep copy

extension CVPixelBuffer {
    func copy() -> CVPixelBuffer {
        precondition(CFGetTypeID(self) == CVPixelBufferGetTypeID(), "copy() cannot be called on a non-CVPixelBuffer")
        
        var _copy : CVPixelBuffer?
        
//        var BytesAlignment:Int = 4
//        let CFBytesAlignment = CFNumberCreate(kCFAllocatorDefault, .intType, &BytesAlignment)!
        let attribute:[String:Any] = [kCVPixelBufferMetalCompatibilityKey as String:kCFBooleanTrue]
//                                      kCVPixelBufferBytesPerRowAlignmentKey as String:CFBytesAlignment
        
        CVPixelBufferCreate(
            kCFAllocatorDefault,
            CVPixelBufferGetWidth(self),
            CVPixelBufferGetHeight(self),
            CVPixelBufferGetPixelFormatType(self),
            attribute as CFDictionary,
            &_copy)
        
        guard let copy = _copy else { fatalError() }
        
        CVPixelBufferLockBaseAddress(self, CVPixelBufferLockFlags.readOnly)
        CVPixelBufferLockBaseAddress(copy, CVPixelBufferLockFlags(rawValue: 0))
        
        for plane in 0..<CVPixelBufferGetPlaneCount(self) {
            let dest = CVPixelBufferGetBaseAddressOfPlane(copy, plane)
            let source = CVPixelBufferGetBaseAddressOfPlane(self, plane)
            let height = CVPixelBufferGetHeightOfPlane(self, plane)
            let bytesPerRow = CVPixelBufferGetBytesPerRowOfPlane(self, plane)
            
            let bytesPerRowDst = CVPixelBufferGetBytesPerRowOfPlane(copy, plane)
            
            for h in 0..<height {
                memcpy(dest?.advanced(by:h*bytesPerRowDst), source?.advanced(by:h*bytesPerRow),  bytesPerRow)
            }
        }
        
        CVPixelBufferUnlockBaseAddress(copy, CVPixelBufferLockFlags(rawValue: 0))
        CVPixelBufferUnlockBaseAddress(self, CVPixelBufferLockFlags.readOnly)
        
        
        return copy
    }
}

https://stackoverflow.com/questions/38335365/pulling-data-from-a-cmsamplebuffer-in-order-to-create-a-deep-copy 

http://blog.csdn.net/fernandowei/article/details/52180840