YSK about Widevine, Google's DRM solution for streaming content. It's used by most top streaming platforms and dictates per-device which video resolutions you're allowed to stream at, regardless of what you pay for.
from /r/YouShouldKnow
YSK关于Widevine，谷歌的流媒体内容的DRM解决方案。它被大多数顶级流媒体平台所使用，并决定了每个设备允许以何种视频分辨率进行流媒体播放，而不管你支付的是什么。