It might still take a long time until all features work in mainline so this might be a stopover for some developers and work better than the 4.4 kernel for now?
I am hoping to reach a new base state for mainline in a week or two, rkvdec high 10/422 h264, vp9 and initial hevc is more or less working (mainly tested on rk3399, probably needs some tuning on rk3328 and rk3288), will post a h264 high-10/422 v3 series on mailing list later this weekend.
There has also been some progress on HDMI side to be able to support proper 10-bit output, color space conversion needs more work before I start posting hdmi patches on mailing list and generate patches for use in LE-master.
Commits · Kwiboo/LibreELEC.tv · GitHub have the latest diff I am testing, this branch should see some updates this weekend and next week, currently missing some bits for 10-bit framebuffers, hevc, hantro interlace due to testing h264 uapi changes.
Regarding PT audio, the Allwinner patches should probably work on RK mainline, I have not tested yet as I want to finalize v4l2 and 10-bit hdmi work before jumping on audio.