Prerecorded video-only: Either an alternative for time-based media or an audio track is provided that presents equivalent information for prerecorded video-only content.

预先录制好的纯视频：为预先录制好的纯音频内容提供一个用于展示等价信息的的基于时间的媒体或者音轨的替代方案。

youdao

Prerecorded video-only: Either an alternative for time-based media or an audio track is provided that presents equivalent information for prerecorded video-only content.

预先录制好的纯音频：为预先录制好的纯音频内容提供一个用于展示等价信息的基于时间的媒体替代方案。

youdao