EME is just an API to access the native code. Levels are primarily about various kinds of hardware protection, I think. The lowest level just uses ordinary sof

EME is just an API to access the native code. Levels are primarily about various kinds of hardware protection, I think. The lowest level just uses ordinary software obfuscation in the widevine library that this article is about, and regular updates to change the media keys. Higher levels integrate more with special hardware "APIs" of various kinds. I think you generally cannot play the highest levels on PC hardware at all, it's more meant for Apple TVs and other such devices. Other levels may require things like the Windows protected media path, which lets you upload encrypted video data to the GPU and then it's up to the GPU firmware to decrypt it. So then it becomes a question of understanding how the GPU is decrypting the data and defeating that.