     // MARK: - private instance vars
     
     internal var sessionIdentifier: String
-    internal var sessionDirectory: String
     internal var sessionDate: Date
     internal var sessionDuration: CMTime
 

            let fileExtension = self.fileExtension
            let filename = "\(self.identifier)-NL-merged.\(fileExtension)"

            let outputURL: URL? = NextLevelClip.clipURL(withFilename: filename, directory: self.sessionDirectory)
            var asset: AVAsset? = nil
            
            if self.sessionClips.count > 0 {

    
    internal func nextFileURL() -> URL? {
        let filename = "\(self.identifier)-NL-clip.\(self.sessionClipFilenameCount).\(self.fileExtension)"
        if let url = NextLevelClip.clipURL(withFilename: filename, directory: self.outputDirectory) {
            self.removeFile(fileUrl: url)
            self.sessionClipFilenameCount += 1
            return url
