Characters used to specify low/standard/medium/high quality/definition in video sharing websites
For streaming video, it is common to say:


低清 (under 480p = 480 horizontal lines)
標清 (DVD resolution: 480p/576p)
高清 (720p or above)


Downloadable videos are sometimes marked as "超高清", which may mean 1080p (or even 4K), or simply a high bitrate 720p encode having excellent quality.