ooOlly's code was not working for me with YUV pixel buffers in all cases (green line at bottom and sig trap in memcpy), so this works in swift for YUV pixel buffers from the camera:
var copyOut: CVPixelBuffer?
let status = CVPixelBufferCreate(kCFAllocatorDefault, CVPixelBufferGetWidth(pixelBuffer), CVPixelBufferGetHeight(pixelBuffer), CVPixelBufferGetPixelFormatType(pixelBuffer), nil, ©Out)
let copy = copyOut!
CVPixelBufferLockBaseAddress(copy, [])
CVPixelBufferLockBaseAddress(pixelBuffer, [])
let ydestPlane = CVPixelBufferGetBaseAddressOfPlane(copy, 0)
let ysrcPlane = CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 0)
memcpy(ydestPlane, ysrcPlane, CVPixelBufferGetBytesPerRowOfPlane(pixelBuffer, 0) * CVPixelBufferGetHeightOfPlane(pixelBuffer, 0))
let uvdestPlane = CVPixelBufferGetBaseAddressOfPlane(copy, 1)
let uvsrcPlane = CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 1)
memcpy(uvdestPlane, uvsrcPlane, CVPixelBufferGetBytesPerRowOfPlane(pixelBuffer, 1) * CVPixelBufferGetHeightOfPlane(pixelBuffer, 1))
CVPixelBufferUnlockBaseAddress(copy, [])
CVPixelBufferUnlockBaseAddress(pixelBuffer, [])
better error handling than the force unwrap is strongly suggested of course.