Afaik netflix uses indeed inputstream adaptive.
But without the cache settings in advanced settings, many movies are unwatchable as the video freezes all the time while sound remains ok. The difference really is night and day here. Same freezing behavior is observed when requesting HEVC in the netflix plugin.
Koboltzz, I hear you, and would be more then happy to do some tests or traces tomorrow to find out more (late here, am in bed right now).
Just let me know what you think makes sence to check.