I read that google and the Alliance for Open Media are making their own codecs (vp9/av1) because of outrageous licencing costs for h265, but i saw that there are open source x265 encoders, that are licenced under gpl v2, so that makes x265 free to use, no?
Then why are google and the Alliance for Open Media making there own codecs?
It's not about the encoding software (encoder), it's about using the encoding algorithm (which is patented) to encode content into a software that is used to re-produce it's information electronically and pass these bits of information along. This re-production of the work is governed by a body that actually not only takes license fees but also controls the use of the that-encoded information.
Inventing your own video codec makes you independent to control from others in that extend.