PINE64

What OS should I use?  All I want to do with the Pine is to use VLC and stream RTP/RTSP feeds

I tried Android 5.1 with touchscreen and VLC has no problem streaming a stream

Now I'm playing with Ubuntu Xenial image  I'm able to open streams but no playback or it's very pixelated, connection is good I'm running another computer on the same network and I have plenty of bandwith. Can the Pine do this without a graphic card?

The answers are in the forum. Essentially in tldr mode: HW acelleration is not yet complete, but it's coming. Have some patience and lurk in the forum.

Xenial image too buggy for VLC Android 5.1 so far so good I can stream 720p. How is it possible to output 4k over HDMI if HW acceleration is not complete?

Because resolution is not dependent on acceleration. Decoding is.