Convert from NStimeInterval to CMTime accurately

Float64 dur = CMTimeGetSeconds([player currentTime]);
Float64 durInMiliSec = 1000*dur;

import CoreMedia
import AVFoundation

let cmTime  = CMTimeMake(10, 20)
let cmValue = NSValue(time: cmTime)

NSDate().timeIntervalSinceDate(serverTime)    

NSDate.timeIntervalSinceDate(serverTime)     

    let time = NSTimeInterval(100)

    let archivedTime = NSKeyedArchiver.archivedDataWithRootObject(time)
    let unarchivedTime = NSKeyedUnarchiver.unarchiveObjectWithData(archivedTime) as! NSTimeInterval

let timeIntvl: TimeInterval = 60
let cmTime = CMTime(seconds: timeIntvl, preferredTimescale: 1000000)