I am new to AWS S3, working on app that will have a number of video files how to upload ? please help..

func uploadData(data: NSData) {
    let expression = AWSS3TransferUtilityUploadExpression()
    expression.progressBlock = progressBlock

    let transferUtility = AWSS3TransferUtility.defaultS3TransferUtility()

    transferUtility.uploadData(
        data,
        bucket: S3BucketName,
        key: S3UploadKeyName,
        contentType: Contenttype,
        expression: expression,
        completionHander: completionHandler).continueWithBlock { (task) -> AnyObject! in
            if let error = task.error {
                NSLog("Error: %@",error.localizedDescription);

            }
            if let exception = task.exception {
                NSLog("Exception: %@",exception.description);

            }
            if let _ = task.result {

                NSLog("Upload Starting!")

            }

            return nil;
    }
}

am doing this but only single video working...