Thank you everyone for testing the devel build. In 2016-10-18 build removed hardware demux patch and added a change to allow playing very high bitrate videos.Now let's try another dev build that has both: hardware demux buffering and a fix for high bitrate stuttering. I believe it also has no video/audio sync issue but I leave it for you to evaluate:
LibreELEC-S905.aarch64-7.0-devel-20161018215738-r23396-g605a453.img.gzPeople with "back key" issue can also try this, I think I finally fixed it - forgive me as I'm still learning sed.
Here, Live TV is perfect. The opening of the first channel is so fast as zapping the channels. And the sync is still perfect.
Thank you very much kszaq. Great Work!