我设法找出添加：
assetImgGenerate.requestedTimeToleranceAfter = kCMTimeZero; assetImgGenerate.requestedTimeToleranceBefore = kCMTimeZero;
…对我的职能将达到目的。
我更新的函数如下所示：
func generateThumnail(url : NSURL, fromTime:Float64) -> UIImage { var asset :AVAsset = AVAsset.assetWithURL(url) as! AVAsset var assetImgGenerate : AVAssetImageGenerator = AVAssetImageGenerator(asset: asset) assetImgGenerate.appliesPreferredTrackTransform = true assetImgGenerate.requestedTimeToleranceAfter = kCMTimeZero; assetImgGenerate.requestedTimeToleranceBefore = kCMTimeZero; var error : NSError? = nil var time : CMTime = CMTimeMakeWithSeconds(fromTime, 600) var img : CGImageRef = assetImgGenerate.copyCGImageAtTime(time, actualTime: nil, error: &error) var frameImg : UIImage = UIImage(CGImage: img)! return frameImg}var grabTime = 1.22img = generateThumnail(urlVideo, fromTime: Float64(grabTime))
