问iOS TXVodDownloadManager 下载加了防盗链的视频，鉴权失败？

let videoId = SuperPlayerVideoId()

videoId.fileId = “a”

videoId.psign = “b”

model.videoId = videoId

model.appId = 1

可以播放视频

let auth = TXPlayerAuthParams()

auth.fileId = "a"

auth.appId = 1

auth.sign = “b”

let ds = TXVodDownloadDataSource()

ds.auth = auth

txDownloader?.startDownload(ds)

下载失败：鉴权失败

fileid,appid,签名确定相同